Merge git://git.kernel.org/pub/scm/linux/kernel/git/pkl/squashfs-linus
* git://git.kernel.org/pub/scm/linux/kernel/git/pkl/squashfs-linus: MAINTAINERS: squashfs entry Squashfs: documentation Squashfs: initrd support Squashfs: Kconfig entry Squashfs: Makefiles Squashfs: header files Squashfs: block operations Squashfs: cache operations Squashfs: uid/gid lookup operations Squashfs: fragment block operations Squashfs: export operations Squashfs: super block operations Squashfs: symlink operations Squashfs: regular file operations Squashfs: directory readdir operations Squashfs: directory lookup operations Squashfs: inode operations
This commit is contained in:
Linus Torvalds
Коммит
31aeb6c815
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@ -0,0 +1,225 @@
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SQUASHFS 4.0 FILESYSTEM
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=======================
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Squashfs is a compressed read-only filesystem for Linux.
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It uses zlib compression to compress files, inodes and directories.
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Inodes in the system are very small and all blocks are packed to minimise
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data overhead. Block sizes greater than 4K are supported up to a maximum
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of 1Mbytes (default block size 128K).
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Squashfs is intended for general read-only filesystem use, for archival
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use (i.e. in cases where a .tar.gz file may be used), and in constrained
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block device/memory systems (e.g. embedded systems) where low overhead is
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needed.
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Mailing list: squashfs-devel@lists.sourceforge.net
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Web site: www.squashfs.org
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1. FILESYSTEM FEATURES
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----------------------
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Squashfs filesystem features versus Cramfs:
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Squashfs Cramfs
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Max filesystem size: 2^64 16 MiB
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Max file size: ~ 2 TiB 16 MiB
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Max files: unlimited unlimited
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Max directories: unlimited unlimited
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Max entries per directory: unlimited unlimited
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Max block size: 1 MiB 4 KiB
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Metadata compression: yes no
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Directory indexes: yes no
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Sparse file support: yes no
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Tail-end packing (fragments): yes no
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Exportable (NFS etc.): yes no
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Hard link support: yes no
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"." and ".." in readdir: yes no
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Real inode numbers: yes no
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32-bit uids/gids: yes no
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File creation time: yes no
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Xattr and ACL support: no no
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Squashfs compresses data, inodes and directories. In addition, inode and
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directory data are highly compacted, and packed on byte boundaries. Each
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compressed inode is on average 8 bytes in length (the exact length varies on
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file type, i.e. regular file, directory, symbolic link, and block/char device
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inodes have different sizes).
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2. USING SQUASHFS
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-----------------
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As squashfs is a read-only filesystem, the mksquashfs program must be used to
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create populated squashfs filesystems. This and other squashfs utilities
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can be obtained from http://www.squashfs.org. Usage instructions can be
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obtained from this site also.
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3. SQUASHFS FILESYSTEM DESIGN
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-----------------------------
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A squashfs filesystem consists of seven parts, packed together on a byte
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alignment:
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---------------
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| superblock |
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|---------------|
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| datablocks |
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| & fragments |
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|---------------|
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| inode table |
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|---------------|
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| directory |
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| table |
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|---------------|
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| fragment |
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| table |
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|---------------|
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| export |
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| table |
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|---------------|
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| uid/gid |
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| lookup table |
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---------------
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Compressed data blocks are written to the filesystem as files are read from
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the source directory, and checked for duplicates. Once all file data has been
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written the completed inode, directory, fragment, export and uid/gid lookup
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tables are written.
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3.1 Inodes
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----------
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Metadata (inodes and directories) are compressed in 8Kbyte blocks. Each
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compressed block is prefixed by a two byte length, the top bit is set if the
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block is uncompressed. A block will be uncompressed if the -noI option is set,
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or if the compressed block was larger than the uncompressed block.
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Inodes are packed into the metadata blocks, and are not aligned to block
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boundaries, therefore inodes overlap compressed blocks. Inodes are identified
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by a 48-bit number which encodes the location of the compressed metadata block
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containing the inode, and the byte offset into that block where the inode is
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placed (<block, offset>).
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To maximise compression there are different inodes for each file type
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(regular file, directory, device, etc.), the inode contents and length
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varying with the type.
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To further maximise compression, two types of regular file inode and
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directory inode are defined: inodes optimised for frequently occurring
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regular files and directories, and extended types where extra
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information has to be stored.
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3.2 Directories
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---------------
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Like inodes, directories are packed into compressed metadata blocks, stored
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in a directory table. Directories are accessed using the start address of
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the metablock containing the directory and the offset into the
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decompressed block (<block, offset>).
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Directories are organised in a slightly complex way, and are not simply
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a list of file names. The organisation takes advantage of the
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fact that (in most cases) the inodes of the files will be in the same
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compressed metadata block, and therefore, can share the start block.
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Directories are therefore organised in a two level list, a directory
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header containing the shared start block value, and a sequence of directory
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entries, each of which share the shared start block. A new directory header
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is written once/if the inode start block changes. The directory
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header/directory entry list is repeated as many times as necessary.
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Directories are sorted, and can contain a directory index to speed up
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file lookup. Directory indexes store one entry per metablock, each entry
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storing the index/filename mapping to the first directory header
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in each metadata block. Directories are sorted in alphabetical order,
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and at lookup the index is scanned linearly looking for the first filename
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alphabetically larger than the filename being looked up. At this point the
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location of the metadata block the filename is in has been found.
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The general idea of the index is ensure only one metadata block needs to be
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decompressed to do a lookup irrespective of the length of the directory.
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This scheme has the advantage that it doesn't require extra memory overhead
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and doesn't require much extra storage on disk.
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3.3 File data
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-------------
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Regular files consist of a sequence of contiguous compressed blocks, and/or a
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compressed fragment block (tail-end packed block). The compressed size
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of each datablock is stored in a block list contained within the
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file inode.
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To speed up access to datablocks when reading 'large' files (256 Mbytes or
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larger), the code implements an index cache that caches the mapping from
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block index to datablock location on disk.
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The index cache allows Squashfs to handle large files (up to 1.75 TiB) while
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retaining a simple and space-efficient block list on disk. The cache
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is split into slots, caching up to eight 224 GiB files (128 KiB blocks).
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Larger files use multiple slots, with 1.75 TiB files using all 8 slots.
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The index cache is designed to be memory efficient, and by default uses
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16 KiB.
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3.4 Fragment lookup table
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-------------------------
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Regular files can contain a fragment index which is mapped to a fragment
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location on disk and compressed size using a fragment lookup table. This
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fragment lookup table is itself stored compressed into metadata blocks.
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A second index table is used to locate these. This second index table for
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speed of access (and because it is small) is read at mount time and cached
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in memory.
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3.5 Uid/gid lookup table
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------------------------
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For space efficiency regular files store uid and gid indexes, which are
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converted to 32-bit uids/gids using an id look up table. This table is
|
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stored compressed into metadata blocks. A second index table is used to
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locate these. This second index table for speed of access (and because it
|
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is small) is read at mount time and cached in memory.
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3.6 Export table
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----------------
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To enable Squashfs filesystems to be exportable (via NFS etc.) filesystems
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can optionally (disabled with the -no-exports Mksquashfs option) contain
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an inode number to inode disk location lookup table. This is required to
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enable Squashfs to map inode numbers passed in filehandles to the inode
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location on disk, which is necessary when the export code reinstantiates
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expired/flushed inodes.
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|
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This table is stored compressed into metadata blocks. A second index table is
|
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used to locate these. This second index table for speed of access (and because
|
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it is small) is read at mount time and cached in memory.
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|
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4. TODOS AND OUTSTANDING ISSUES
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-------------------------------
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4.1 Todo list
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||||
-------------
|
||||
|
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Implement Xattr and ACL support. The Squashfs 4.0 filesystem layout has hooks
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for these but the code has not been written. Once the code has been written
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the existing layout should not require modification.
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|
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4.2 Squashfs internal cache
|
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---------------------------
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Blocks in Squashfs are compressed. To avoid repeatedly decompressing
|
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recently accessed data Squashfs uses two small metadata and fragment caches.
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The cache is not used for file datablocks, these are decompressed and cached in
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the page-cache in the normal way. The cache is used to temporarily cache
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fragment and metadata blocks which have been read as a result of a metadata
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(i.e. inode or directory) or fragment access. Because metadata and fragments
|
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are packed together into blocks (to gain greater compression) the read of a
|
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particular piece of metadata or fragment will retrieve other metadata/fragments
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which have been packed with it, these because of locality-of-reference may be
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read in the near future. Temporarily caching them ensures they are available
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for near future access without requiring an additional read and decompress.
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In the future this internal cache may be replaced with an implementation which
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uses the kernel page cache. Because the page cache operates on page sized
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units this may introduce additional complexity in terms of locking and
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associated race conditions.
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|
|
@ -4081,6 +4081,13 @@ L: cbe-oss-dev@ozlabs.org
|
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W: http://www.ibm.com/developerworks/power/cell/
|
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S: Supported
|
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|
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SQUASHFS FILE SYSTEM
|
||||
P: Phillip Lougher
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M: phillip@lougher.demon.co.uk
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L: squashfs-devel@lists.sourceforge.net (subscribers-only)
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W: http://squashfs.org.uk
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S: Maintained
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SRM (Alpha) environment access
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P: Jan-Benedict Glaw
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M: jbglaw@lug-owl.de
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|
|
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52
fs/Kconfig
52
fs/Kconfig
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|
@ -932,6 +932,58 @@ config CRAMFS
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If unsure, say N.
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config SQUASHFS
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tristate "SquashFS 4.0 - Squashed file system support"
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depends on BLOCK
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select ZLIB_INFLATE
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help
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Saying Y here includes support for SquashFS 4.0 (a Compressed
|
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Read-Only File System). Squashfs is a highly compressed read-only
|
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filesystem for Linux. It uses zlib compression to compress both
|
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files, inodes and directories. Inodes in the system are very small
|
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and all blocks are packed to minimise data overhead. Block sizes
|
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greater than 4K are supported up to a maximum of 1 Mbytes (default
|
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block size 128K). SquashFS 4.0 supports 64 bit filesystems and files
|
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(larger than 4GB), full uid/gid information, hard links and
|
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timestamps.
|
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|
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Squashfs is intended for general read-only filesystem use, for
|
||||
archival use (i.e. in cases where a .tar.gz file may be used), and in
|
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embedded systems where low overhead is needed. Further information
|
||||
and tools are available from http://squashfs.sourceforge.net.
|
||||
|
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If you want to compile this as a module ( = code which can be
|
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inserted in and removed from the running kernel whenever you want),
|
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say M here and read <file:Documentation/modules.txt>. The module
|
||||
will be called squashfs. Note that the root file system (the one
|
||||
containing the directory /) cannot be compiled as a module.
|
||||
|
||||
If unsure, say N.
|
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|
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config SQUASHFS_EMBEDDED
|
||||
|
||||
bool "Additional option for memory-constrained systems"
|
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depends on SQUASHFS
|
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default n
|
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help
|
||||
Saying Y here allows you to specify cache size.
|
||||
|
||||
If unsure, say N.
|
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|
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config SQUASHFS_FRAGMENT_CACHE_SIZE
|
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int "Number of fragments cached" if SQUASHFS_EMBEDDED
|
||||
depends on SQUASHFS
|
||||
default "3"
|
||||
help
|
||||
By default SquashFS caches the last 3 fragments read from
|
||||
the filesystem. Increasing this amount may mean SquashFS
|
||||
has to re-read fragments less often from disk, at the expense
|
||||
of extra system memory. Decreasing this amount will mean
|
||||
SquashFS uses less memory at the expense of extra reads from disk.
|
||||
|
||||
Note there must be at least one cached fragment. Anything
|
||||
much more than three will probably not make much difference.
|
||||
|
||||
config VXFS_FS
|
||||
tristate "FreeVxFS file system support (VERITAS VxFS(TM) compatible)"
|
||||
depends on BLOCK
|
||||
|
|
|
|||
|
|
@ -74,6 +74,7 @@ obj-$(CONFIG_JBD) += jbd/
|
|||
obj-$(CONFIG_JBD2) += jbd2/
|
||||
obj-$(CONFIG_EXT2_FS) += ext2/
|
||||
obj-$(CONFIG_CRAMFS) += cramfs/
|
||||
obj-$(CONFIG_SQUASHFS) += squashfs/
|
||||
obj-y += ramfs/
|
||||
obj-$(CONFIG_HUGETLBFS) += hugetlbfs/
|
||||
obj-$(CONFIG_CODA_FS) += coda/
|
||||
|
|
|
|||
|
|
@ -0,0 +1,8 @@
|
|||
#
|
||||
# Makefile for the linux squashfs routines.
|
||||
#
|
||||
|
||||
obj-$(CONFIG_SQUASHFS) += squashfs.o
|
||||
squashfs-y += block.o cache.o dir.o export.o file.o fragment.o id.o inode.o
|
||||
squashfs-y += namei.o super.o symlink.o
|
||||
#squashfs-y += squashfs2_0.o
|
||||
|
|
@ -0,0 +1,274 @@
|
|||
/*
|
||||
* Squashfs - a compressed read only filesystem for Linux
|
||||
*
|
||||
* Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008
|
||||
* Phillip Lougher <phillip@lougher.demon.co.uk>
|
||||
*
|
||||
* This program is free software; you can redistribute it and/or
|
||||
* modify it under the terms of the GNU General Public License
|
||||
* as published by the Free Software Foundation; either version 2,
|
||||
* or (at your option) any later version.
|
||||
*
|
||||
* This program is distributed in the hope that it will be useful,
|
||||
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||||
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
||||
* GNU General Public License for more details.
|
||||
*
|
||||
* You should have received a copy of the GNU General Public License
|
||||
* along with this program; if not, write to the Free Software
|
||||
* Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
|
||||
*
|
||||
* block.c
|
||||
*/
|
||||
|
||||
/*
|
||||
* This file implements the low-level routines to read and decompress
|
||||
* datablocks and metadata blocks.
|
||||
*/
|
||||
|
||||
#include <linux/fs.h>
|
||||
#include <linux/vfs.h>
|
||||
#include <linux/slab.h>
|
||||
#include <linux/mutex.h>
|
||||
#include <linux/string.h>
|
||||
#include <linux/buffer_head.h>
|
||||
#include <linux/zlib.h>
|
||||
|
||||
#include "squashfs_fs.h"
|
||||
#include "squashfs_fs_sb.h"
|
||||
#include "squashfs_fs_i.h"
|
||||
#include "squashfs.h"
|
||||
|
||||
/*
|
||||
* Read the metadata block length, this is stored in the first two
|
||||
* bytes of the metadata block.
|
||||
*/
|
||||
static struct buffer_head *get_block_length(struct super_block *sb,
|
||||
u64 *cur_index, int *offset, int *length)
|
||||
{
|
||||
struct squashfs_sb_info *msblk = sb->s_fs_info;
|
||||
struct buffer_head *bh;
|
||||
|
||||
bh = sb_bread(sb, *cur_index);
|
||||
if (bh == NULL)
|
||||
return NULL;
|
||||
|
||||
if (msblk->devblksize - *offset == 1) {
|
||||
*length = (unsigned char) bh->b_data[*offset];
|
||||
put_bh(bh);
|
||||
bh = sb_bread(sb, ++(*cur_index));
|
||||
if (bh == NULL)
|
||||
return NULL;
|
||||
*length |= (unsigned char) bh->b_data[0] << 8;
|
||||
*offset = 1;
|
||||
} else {
|
||||
*length = (unsigned char) bh->b_data[*offset] |
|
||||
(unsigned char) bh->b_data[*offset + 1] << 8;
|
||||
*offset += 2;
|
||||
}
|
||||
|
||||
return bh;
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
* Read and decompress a metadata block or datablock. Length is non-zero
|
||||
* if a datablock is being read (the size is stored elsewhere in the
|
||||
* filesystem), otherwise the length is obtained from the first two bytes of
|
||||
* the metadata block. A bit in the length field indicates if the block
|
||||
* is stored uncompressed in the filesystem (usually because compression
|
||||
* generated a larger block - this does occasionally happen with zlib).
|
||||
*/
|
||||
int squashfs_read_data(struct super_block *sb, void **buffer, u64 index,
|
||||
int length, u64 *next_index, int srclength)
|
||||
{
|
||||
struct squashfs_sb_info *msblk = sb->s_fs_info;
|
||||
struct buffer_head **bh;
|
||||
int offset = index & ((1 << msblk->devblksize_log2) - 1);
|
||||
u64 cur_index = index >> msblk->devblksize_log2;
|
||||
int bytes, compressed, b = 0, k = 0, page = 0, avail;
|
||||
|
||||
|
||||
bh = kcalloc((msblk->block_size >> msblk->devblksize_log2) + 1,
|
||||
sizeof(*bh), GFP_KERNEL);
|
||||
if (bh == NULL)
|
||||
return -ENOMEM;
|
||||
|
||||
if (length) {
|
||||
/*
|
||||
* Datablock.
|
||||
*/
|
||||
bytes = -offset;
|
||||
compressed = SQUASHFS_COMPRESSED_BLOCK(length);
|
||||
length = SQUASHFS_COMPRESSED_SIZE_BLOCK(length);
|
||||
if (next_index)
|
||||
*next_index = index + length;
|
||||
|
||||
TRACE("Block @ 0x%llx, %scompressed size %d, src size %d\n",
|
||||
index, compressed ? "" : "un", length, srclength);
|
||||
|
||||
if (length < 0 || length > srclength ||
|
||||
(index + length) > msblk->bytes_used)
|
||||
goto read_failure;
|
||||
|
||||
for (b = 0; bytes < length; b++, cur_index++) {
|
||||
bh[b] = sb_getblk(sb, cur_index);
|
||||
if (bh[b] == NULL)
|
||||
goto block_release;
|
||||
bytes += msblk->devblksize;
|
||||
}
|
||||
ll_rw_block(READ, b, bh);
|
||||
} else {
|
||||
/*
|
||||
* Metadata block.
|
||||
*/
|
||||
if ((index + 2) > msblk->bytes_used)
|
||||
goto read_failure;
|
||||
|
||||
bh[0] = get_block_length(sb, &cur_index, &offset, &length);
|
||||
if (bh[0] == NULL)
|
||||
goto read_failure;
|
||||
b = 1;
|
||||
|
||||
bytes = msblk->devblksize - offset;
|
||||
compressed = SQUASHFS_COMPRESSED(length);
|
||||
length = SQUASHFS_COMPRESSED_SIZE(length);
|
||||
if (next_index)
|
||||
*next_index = index + length + 2;
|
||||
|
||||
TRACE("Block @ 0x%llx, %scompressed size %d\n", index,
|
||||
compressed ? "" : "un", length);
|
||||
|
||||
if (length < 0 || length > srclength ||
|
||||
(index + length) > msblk->bytes_used)
|
||||
goto block_release;
|
||||
|
||||
for (; bytes < length; b++) {
|
||||
bh[b] = sb_getblk(sb, ++cur_index);
|
||||
if (bh[b] == NULL)
|
||||
goto block_release;
|
||||
bytes += msblk->devblksize;
|
||||
}
|
||||
ll_rw_block(READ, b - 1, bh + 1);
|
||||
}
|
||||
|
||||
if (compressed) {
|
||||
int zlib_err = 0, zlib_init = 0;
|
||||
|
||||
/*
|
||||
* Uncompress block.
|
||||
*/
|
||||
|
||||
mutex_lock(&msblk->read_data_mutex);
|
||||
|
||||
msblk->stream.avail_out = 0;
|
||||
msblk->stream.avail_in = 0;
|
||||
|
||||
bytes = length;
|
||||
do {
|
||||
if (msblk->stream.avail_in == 0 && k < b) {
|
||||
avail = min(bytes, msblk->devblksize - offset);
|
||||
bytes -= avail;
|
||||
wait_on_buffer(bh[k]);
|
||||
if (!buffer_uptodate(bh[k]))
|
||||
goto release_mutex;
|
||||
|
||||
if (avail == 0) {
|
||||
offset = 0;
|
||||
put_bh(bh[k++]);
|
||||
continue;
|
||||
}
|
||||
|
||||
msblk->stream.next_in = bh[k]->b_data + offset;
|
||||
msblk->stream.avail_in = avail;
|
||||
offset = 0;
|
||||
}
|
||||
|
||||
if (msblk->stream.avail_out == 0) {
|
||||
msblk->stream.next_out = buffer[page++];
|
||||
msblk->stream.avail_out = PAGE_CACHE_SIZE;
|
||||
}
|
||||
|
||||
if (!zlib_init) {
|
||||
zlib_err = zlib_inflateInit(&msblk->stream);
|
||||
if (zlib_err != Z_OK) {
|
||||
ERROR("zlib_inflateInit returned"
|
||||
" unexpected result 0x%x,"
|
||||
" srclength %d\n", zlib_err,
|
||||
srclength);
|
||||
goto release_mutex;
|
||||
}
|
||||
zlib_init = 1;
|
||||
}
|
||||
|
||||
zlib_err = zlib_inflate(&msblk->stream, Z_NO_FLUSH);
|
||||
|
||||
if (msblk->stream.avail_in == 0 && k < b)
|
||||
put_bh(bh[k++]);
|
||||
} while (zlib_err == Z_OK);
|
||||
|
||||
if (zlib_err != Z_STREAM_END) {
|
||||
ERROR("zlib_inflate returned unexpected result"
|
||||
" 0x%x, srclength %d, avail_in %d,"
|
||||
" avail_out %d\n", zlib_err, srclength,
|
||||
msblk->stream.avail_in,
|
||||
msblk->stream.avail_out);
|
||||
goto release_mutex;
|
||||
}
|
||||
|
||||
zlib_err = zlib_inflateEnd(&msblk->stream);
|
||||
if (zlib_err != Z_OK) {
|
||||
ERROR("zlib_inflateEnd returned unexpected result 0x%x,"
|
||||
" srclength %d\n", zlib_err, srclength);
|
||||
goto release_mutex;
|
||||
}
|
||||
length = msblk->stream.total_out;
|
||||
mutex_unlock(&msblk->read_data_mutex);
|
||||
} else {
|
||||
/*
|
||||
* Block is uncompressed.
|
||||
*/
|
||||
int i, in, pg_offset = 0;
|
||||
|
||||
for (i = 0; i < b; i++) {
|
||||
wait_on_buffer(bh[i]);
|
||||
if (!buffer_uptodate(bh[i]))
|
||||
goto block_release;
|
||||
}
|
||||
|
||||
for (bytes = length; k < b; k++) {
|
||||
in = min(bytes, msblk->devblksize - offset);
|
||||
bytes -= in;
|
||||
while (in) {
|
||||
if (pg_offset == PAGE_CACHE_SIZE) {
|
||||
page++;
|
||||
pg_offset = 0;
|
||||
}
|
||||
avail = min_t(int, in, PAGE_CACHE_SIZE -
|
||||
pg_offset);
|
||||
memcpy(buffer[page] + pg_offset,
|
||||
bh[k]->b_data + offset, avail);
|
||||
in -= avail;
|
||||
pg_offset += avail;
|
||||
offset += avail;
|
||||
}
|
||||
offset = 0;
|
||||
put_bh(bh[k]);
|
||||
}
|
||||
}
|
||||
|
||||
kfree(bh);
|
||||
return length;
|
||||
|
||||
release_mutex:
|
||||
mutex_unlock(&msblk->read_data_mutex);
|
||||
|
||||
block_release:
|
||||
for (; k < b; k++)
|
||||
put_bh(bh[k]);
|
||||
|
||||
read_failure:
|
||||
ERROR("sb_bread failed reading block 0x%llx\n", cur_index);
|
||||
kfree(bh);
|
||||
return -EIO;
|
||||
}
|
||||
|
|
@ -0,0 +1,412 @@
|
|||
/*
|
||||
* Squashfs - a compressed read only filesystem for Linux
|
||||
*
|
||||
* Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008
|
||||
* Phillip Lougher <phillip@lougher.demon.co.uk>
|
||||
*
|
||||
* This program is free software; you can redistribute it and/or
|
||||
* modify it under the terms of the GNU General Public License
|
||||
* as published by the Free Software Foundation; either version 2,
|
||||
* or (at your option) any later version.
|
||||
*
|
||||
* This program is distributed in the hope that it will be useful,
|
||||
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||||
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
||||
* GNU General Public License for more details.
|
||||
*
|
||||
* You should have received a copy of the GNU General Public License
|
||||
* along with this program; if not, write to the Free Software
|
||||
* Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
|
||||
*
|
||||
* cache.c
|
||||
*/
|
||||
|
||||
/*
|
||||
* Blocks in Squashfs are compressed. To avoid repeatedly decompressing
|
||||
* recently accessed data Squashfs uses two small metadata and fragment caches.
|
||||
*
|
||||
* This file implements a generic cache implementation used for both caches,
|
||||
* plus functions layered ontop of the generic cache implementation to
|
||||
* access the metadata and fragment caches.
|
||||
*
|
||||
* To avoid out of memory and fragmentation isssues with vmalloc the cache
|
||||
* uses sequences of kmalloced PAGE_CACHE_SIZE buffers.
|
||||
*
|
||||
* It should be noted that the cache is not used for file datablocks, these
|
||||
* are decompressed and cached in the page-cache in the normal way. The
|
||||
* cache is only used to temporarily cache fragment and metadata blocks
|
||||
* which have been read as as a result of a metadata (i.e. inode or
|
||||
* directory) or fragment access. Because metadata and fragments are packed
|
||||
* together into blocks (to gain greater compression) the read of a particular
|
||||
* piece of metadata or fragment will retrieve other metadata/fragments which
|
||||
* have been packed with it, these because of locality-of-reference may be read
|
||||
* in the near future. Temporarily caching them ensures they are available for
|
||||
* near future access without requiring an additional read and decompress.
|
||||
*/
|
||||
|
||||
#include <linux/fs.h>
|
||||
#include <linux/vfs.h>
|
||||
#include <linux/slab.h>
|
||||
#include <linux/vmalloc.h>
|
||||
#include <linux/sched.h>
|
||||
#include <linux/spinlock.h>
|
||||
#include <linux/wait.h>
|
||||
#include <linux/zlib.h>
|
||||
#include <linux/pagemap.h>
|
||||
|
||||
#include "squashfs_fs.h"
|
||||
#include "squashfs_fs_sb.h"
|
||||
#include "squashfs_fs_i.h"
|
||||
#include "squashfs.h"
|
||||
|
||||
/*
|
||||
* Look-up block in cache, and increment usage count. If not in cache, read
|
||||
* and decompress it from disk.
|
||||
*/
|
||||
struct squashfs_cache_entry *squashfs_cache_get(struct super_block *sb,
|
||||
struct squashfs_cache *cache, u64 block, int length)
|
||||
{
|
||||
int i, n;
|
||||
struct squashfs_cache_entry *entry;
|
||||
|
||||
spin_lock(&cache->lock);
|
||||
|
||||
while (1) {
|
||||
for (i = 0; i < cache->entries; i++)
|
||||
if (cache->entry[i].block == block)
|
||||
break;
|
||||
|
||||
if (i == cache->entries) {
|
||||
/*
|
||||
* Block not in cache, if all cache entries are used
|
||||
* go to sleep waiting for one to become available.
|
||||
*/
|
||||
if (cache->unused == 0) {
|
||||
cache->num_waiters++;
|
||||
spin_unlock(&cache->lock);
|
||||
wait_event(cache->wait_queue, cache->unused);
|
||||
spin_lock(&cache->lock);
|
||||
cache->num_waiters--;
|
||||
continue;
|
||||
}
|
||||
|
||||
/*
|
||||
* At least one unused cache entry. A simple
|
||||
* round-robin strategy is used to choose the entry to
|
||||
* be evicted from the cache.
|
||||
*/
|
||||
i = cache->next_blk;
|
||||
for (n = 0; n < cache->entries; n++) {
|
||||
if (cache->entry[i].refcount == 0)
|
||||
break;
|
||||
i = (i + 1) % cache->entries;
|
||||
}
|
||||
|
||||
cache->next_blk = (i + 1) % cache->entries;
|
||||
entry = &cache->entry[i];
|
||||
|
||||
/*
|
||||
* Initialise choosen cache entry, and fill it in from
|
||||
* disk.
|
||||
*/
|
||||
cache->unused--;
|
||||
entry->block = block;
|
||||
entry->refcount = 1;
|
||||
entry->pending = 1;
|
||||
entry->num_waiters = 0;
|
||||
entry->error = 0;
|
||||
spin_unlock(&cache->lock);
|
||||
|
||||
entry->length = squashfs_read_data(sb, entry->data,
|
||||
block, length, &entry->next_index,
|
||||
cache->block_size);
|
||||
|
||||
spin_lock(&cache->lock);
|
||||
|
||||
if (entry->length < 0)
|
||||
entry->error = entry->length;
|
||||
|
||||
entry->pending = 0;
|
||||
|
||||
/*
|
||||
* While filling this entry one or more other processes
|
||||
* have looked it up in the cache, and have slept
|
||||
* waiting for it to become available.
|
||||
*/
|
||||
if (entry->num_waiters) {
|
||||
spin_unlock(&cache->lock);
|
||||
wake_up_all(&entry->wait_queue);
|
||||
} else
|
||||
spin_unlock(&cache->lock);
|
||||
|
||||
goto out;
|
||||
}
|
||||
|
||||
/*
|
||||
* Block already in cache. Increment refcount so it doesn't
|
||||
* get reused until we're finished with it, if it was
|
||||
* previously unused there's one less cache entry available
|
||||
* for reuse.
|
||||
*/
|
||||
entry = &cache->entry[i];
|
||||
if (entry->refcount == 0)
|
||||
cache->unused--;
|
||||
entry->refcount++;
|
||||
|
||||
/*
|
||||
* If the entry is currently being filled in by another process
|
||||
* go to sleep waiting for it to become available.
|
||||
*/
|
||||
if (entry->pending) {
|
||||
entry->num_waiters++;
|
||||
spin_unlock(&cache->lock);
|
||||
wait_event(entry->wait_queue, !entry->pending);
|
||||
} else
|
||||
spin_unlock(&cache->lock);
|
||||
|
||||
goto out;
|
||||
}
|
||||
|
||||
out:
|
||||
TRACE("Got %s %d, start block %lld, refcount %d, error %d\n",
|
||||
cache->name, i, entry->block, entry->refcount, entry->error);
|
||||
|
||||
if (entry->error)
|
||||
ERROR("Unable to read %s cache entry [%llx]\n", cache->name,
|
||||
block);
|
||||
return entry;
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
* Release cache entry, once usage count is zero it can be reused.
|
||||
*/
|
||||
void squashfs_cache_put(struct squashfs_cache_entry *entry)
|
||||
{
|
||||
struct squashfs_cache *cache = entry->cache;
|
||||
|
||||
spin_lock(&cache->lock);
|
||||
entry->refcount--;
|
||||
if (entry->refcount == 0) {
|
||||
cache->unused++;
|
||||
/*
|
||||
* If there's any processes waiting for a block to become
|
||||
* available, wake one up.
|
||||
*/
|
||||
if (cache->num_waiters) {
|
||||
spin_unlock(&cache->lock);
|
||||
wake_up(&cache->wait_queue);
|
||||
return;
|
||||
}
|
||||
}
|
||||
spin_unlock(&cache->lock);
|
||||
}
|
||||
|
||||
/*
|
||||
* Delete cache reclaiming all kmalloced buffers.
|
||||
*/
|
||||
void squashfs_cache_delete(struct squashfs_cache *cache)
|
||||
{
|
||||
int i, j;
|
||||
|
||||
if (cache == NULL)
|
||||
return;
|
||||
|
||||
for (i = 0; i < cache->entries; i++) {
|
||||
if (cache->entry[i].data) {
|
||||
for (j = 0; j < cache->pages; j++)
|
||||
kfree(cache->entry[i].data[j]);
|
||||
kfree(cache->entry[i].data);
|
||||
}
|
||||
}
|
||||
|
||||
kfree(cache->entry);
|
||||
kfree(cache);
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
* Initialise cache allocating the specified number of entries, each of
|
||||
* size block_size. To avoid vmalloc fragmentation issues each entry
|
||||
* is allocated as a sequence of kmalloced PAGE_CACHE_SIZE buffers.
|
||||
*/
|
||||
struct squashfs_cache *squashfs_cache_init(char *name, int entries,
|
||||
int block_size)
|
||||
{
|
||||
int i, j;
|
||||
struct squashfs_cache *cache = kzalloc(sizeof(*cache), GFP_KERNEL);
|
||||
|
||||
if (cache == NULL) {
|
||||
ERROR("Failed to allocate %s cache\n", name);
|
||||
return NULL;
|
||||
}
|
||||
|
||||
cache->entry = kcalloc(entries, sizeof(*(cache->entry)), GFP_KERNEL);
|
||||
if (cache->entry == NULL) {
|
||||
ERROR("Failed to allocate %s cache\n", name);
|
||||
goto cleanup;
|
||||
}
|
||||
|
||||
cache->next_blk = 0;
|
||||
cache->unused = entries;
|
||||
cache->entries = entries;
|
||||
cache->block_size = block_size;
|
||||
cache->pages = block_size >> PAGE_CACHE_SHIFT;
|
||||
cache->name = name;
|
||||
cache->num_waiters = 0;
|
||||
spin_lock_init(&cache->lock);
|
||||
init_waitqueue_head(&cache->wait_queue);
|
||||
|
||||
for (i = 0; i < entries; i++) {
|
||||
struct squashfs_cache_entry *entry = &cache->entry[i];
|
||||
|
||||
init_waitqueue_head(&cache->entry[i].wait_queue);
|
||||
entry->cache = cache;
|
||||
entry->block = SQUASHFS_INVALID_BLK;
|
||||
entry->data = kcalloc(cache->pages, sizeof(void *), GFP_KERNEL);
|
||||
if (entry->data == NULL) {
|
||||
ERROR("Failed to allocate %s cache entry\n", name);
|
||||
goto cleanup;
|
||||
}
|
||||
|
||||
for (j = 0; j < cache->pages; j++) {
|
||||
entry->data[j] = kmalloc(PAGE_CACHE_SIZE, GFP_KERNEL);
|
||||
if (entry->data[j] == NULL) {
|
||||
ERROR("Failed to allocate %s buffer\n", name);
|
||||
goto cleanup;
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
return cache;
|
||||
|
||||
cleanup:
|
||||
squashfs_cache_delete(cache);
|
||||
return NULL;
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
* Copy upto length bytes from cache entry to buffer starting at offset bytes
|
||||
* into the cache entry. If there's not length bytes then copy the number of
|
||||
* bytes available. In all cases return the number of bytes copied.
|
||||
*/
|
||||
int squashfs_copy_data(void *buffer, struct squashfs_cache_entry *entry,
|
||||
int offset, int length)
|
||||
{
|
||||
int remaining = length;
|
||||
|
||||
if (length == 0)
|
||||
return 0;
|
||||
else if (buffer == NULL)
|
||||
return min(length, entry->length - offset);
|
||||
|
||||
while (offset < entry->length) {
|
||||
void *buff = entry->data[offset / PAGE_CACHE_SIZE]
|
||||
+ (offset % PAGE_CACHE_SIZE);
|
||||
int bytes = min_t(int, entry->length - offset,
|
||||
PAGE_CACHE_SIZE - (offset % PAGE_CACHE_SIZE));
|
||||
|
||||
if (bytes >= remaining) {
|
||||
memcpy(buffer, buff, remaining);
|
||||
remaining = 0;
|
||||
break;
|
||||
}
|
||||
|
||||
memcpy(buffer, buff, bytes);
|
||||
buffer += bytes;
|
||||
remaining -= bytes;
|
||||
offset += bytes;
|
||||
}
|
||||
|
||||
return length - remaining;
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
* Read length bytes from metadata position <block, offset> (block is the
|
||||
* start of the compressed block on disk, and offset is the offset into
|
||||
* the block once decompressed). Data is packed into consecutive blocks,
|
||||
* and length bytes may require reading more than one block.
|
||||
*/
|
||||
int squashfs_read_metadata(struct super_block *sb, void *buffer,
|
||||
u64 *block, int *offset, int length)
|
||||
{
|
||||
struct squashfs_sb_info *msblk = sb->s_fs_info;
|
||||
int bytes, copied = length;
|
||||
struct squashfs_cache_entry *entry;
|
||||
|
||||
TRACE("Entered squashfs_read_metadata [%llx:%x]\n", *block, *offset);
|
||||
|
||||
while (length) {
|
||||
entry = squashfs_cache_get(sb, msblk->block_cache, *block, 0);
|
||||
if (entry->error)
|
||||
return entry->error;
|
||||
else if (*offset >= entry->length)
|
||||
return -EIO;
|
||||
|
||||
bytes = squashfs_copy_data(buffer, entry, *offset, length);
|
||||
if (buffer)
|
||||
buffer += bytes;
|
||||
length -= bytes;
|
||||
*offset += bytes;
|
||||
|
||||
if (*offset == entry->length) {
|
||||
*block = entry->next_index;
|
||||
*offset = 0;
|
||||
}
|
||||
|
||||
squashfs_cache_put(entry);
|
||||
}
|
||||
|
||||
return copied;
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
* Look-up in the fragmment cache the fragment located at <start_block> in the
|
||||
* filesystem. If necessary read and decompress it from disk.
|
||||
*/
|
||||
struct squashfs_cache_entry *squashfs_get_fragment(struct super_block *sb,
|
||||
u64 start_block, int length)
|
||||
{
|
||||
struct squashfs_sb_info *msblk = sb->s_fs_info;
|
||||
|
||||
return squashfs_cache_get(sb, msblk->fragment_cache, start_block,
|
||||
length);
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
* Read and decompress the datablock located at <start_block> in the
|
||||
* filesystem. The cache is used here to avoid duplicating locking and
|
||||
* read/decompress code.
|
||||
*/
|
||||
struct squashfs_cache_entry *squashfs_get_datablock(struct super_block *sb,
|
||||
u64 start_block, int length)
|
||||
{
|
||||
struct squashfs_sb_info *msblk = sb->s_fs_info;
|
||||
|
||||
return squashfs_cache_get(sb, msblk->read_page, start_block, length);
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
* Read a filesystem table (uncompressed sequence of bytes) from disk
|
||||
*/
|
||||
int squashfs_read_table(struct super_block *sb, void *buffer, u64 block,
|
||||
int length)
|
||||
{
|
||||
int pages = (length + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
|
||||
int i, res;
|
||||
void **data = kcalloc(pages, sizeof(void *), GFP_KERNEL);
|
||||
if (data == NULL)
|
||||
return -ENOMEM;
|
||||
|
||||
for (i = 0; i < pages; i++, buffer += PAGE_CACHE_SIZE)
|
||||
data[i] = buffer;
|
||||
res = squashfs_read_data(sb, data, block, length |
|
||||
SQUASHFS_COMPRESSED_BIT_BLOCK, NULL, length);
|
||||
kfree(data);
|
||||
return res;
|
||||
}
|
||||
|
|
@ -0,0 +1,235 @@
|
|||
/*
|
||||
* Squashfs - a compressed read only filesystem for Linux
|
||||
*
|
||||
* Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008
|
||||
* Phillip Lougher <phillip@lougher.demon.co.uk>
|
||||
*
|
||||
* This program is free software; you can redistribute it and/or
|
||||
* modify it under the terms of the GNU General Public License
|
||||
* as published by the Free Software Foundation; either version 2,
|
||||
* or (at your option) any later version.
|
||||
*
|
||||
* This program is distributed in the hope that it will be useful,
|
||||
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||||
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
||||
* GNU General Public License for more details.
|
||||
*
|
||||
* You should have received a copy of the GNU General Public License
|
||||
* along with this program; if not, write to the Free Software
|
||||
* Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
|
||||
*
|
||||
* dir.c
|
||||
*/
|
||||
|
||||
/*
|
||||
* This file implements code to read directories from disk.
|
||||
*
|
||||
* See namei.c for a description of directory organisation on disk.
|
||||
*/
|
||||
|
||||
#include <linux/fs.h>
|
||||
#include <linux/vfs.h>
|
||||
#include <linux/slab.h>
|
||||
#include <linux/zlib.h>
|
||||
|
||||
#include "squashfs_fs.h"
|
||||
#include "squashfs_fs_sb.h"
|
||||
#include "squashfs_fs_i.h"
|
||||
#include "squashfs.h"
|
||||
|
||||
static const unsigned char squashfs_filetype_table[] = {
|
||||
DT_UNKNOWN, DT_DIR, DT_REG, DT_LNK, DT_BLK, DT_CHR, DT_FIFO, DT_SOCK
|
||||
};
|
||||
|
||||
/*
|
||||
* Lookup offset (f_pos) in the directory index, returning the
|
||||
* metadata block containing it.
|
||||
*
|
||||
* If we get an error reading the index then return the part of the index
|
||||
* (if any) we have managed to read - the index isn't essential, just
|
||||
* quicker.
|
||||
*/
|
||||
static int get_dir_index_using_offset(struct super_block *sb,
|
||||
u64 *next_block, int *next_offset, u64 index_start, int index_offset,
|
||||
int i_count, u64 f_pos)
|
||||
{
|
||||
struct squashfs_sb_info *msblk = sb->s_fs_info;
|
||||
int err, i, index, length = 0;
|
||||
struct squashfs_dir_index dir_index;
|
||||
|
||||
TRACE("Entered get_dir_index_using_offset, i_count %d, f_pos %lld\n",
|
||||
i_count, f_pos);
|
||||
|
||||
/*
|
||||
* Translate from external f_pos to the internal f_pos. This
|
||||
* is offset by 3 because we invent "." and ".." entries which are
|
||||
* not actually stored in the directory.
|
||||
*/
|
||||
if (f_pos < 3)
|
||||
return f_pos;
|
||||
f_pos -= 3;
|
||||
|
||||
for (i = 0; i < i_count; i++) {
|
||||
err = squashfs_read_metadata(sb, &dir_index, &index_start,
|
||||
&index_offset, sizeof(dir_index));
|
||||
if (err < 0)
|
||||
break;
|
||||
|
||||
index = le32_to_cpu(dir_index.index);
|
||||
if (index > f_pos)
|
||||
/*
|
||||
* Found the index we're looking for.
|
||||
*/
|
||||
break;
|
||||
|
||||
err = squashfs_read_metadata(sb, NULL, &index_start,
|
||||
&index_offset, le32_to_cpu(dir_index.size) + 1);
|
||||
if (err < 0)
|
||||
break;
|
||||
|
||||
length = index;
|
||||
*next_block = le32_to_cpu(dir_index.start_block) +
|
||||
msblk->directory_table;
|
||||
}
|
||||
|
||||
*next_offset = (length + *next_offset) % SQUASHFS_METADATA_SIZE;
|
||||
|
||||
/*
|
||||
* Translate back from internal f_pos to external f_pos.
|
||||
*/
|
||||
return length + 3;
|
||||
}
|
||||
|
||||
|
||||
static int squashfs_readdir(struct file *file, void *dirent, filldir_t filldir)
|
||||
{
|
||||
struct inode *inode = file->f_dentry->d_inode;
|
||||
struct squashfs_sb_info *msblk = inode->i_sb->s_fs_info;
|
||||
u64 block = squashfs_i(inode)->start + msblk->directory_table;
|
||||
int offset = squashfs_i(inode)->offset, length = 0, dir_count, size,
|
||||
type, err;
|
||||
unsigned int inode_number;
|
||||
struct squashfs_dir_header dirh;
|
||||
struct squashfs_dir_entry *dire;
|
||||
|
||||
TRACE("Entered squashfs_readdir [%llx:%x]\n", block, offset);
|
||||
|
||||
dire = kmalloc(sizeof(*dire) + SQUASHFS_NAME_LEN + 1, GFP_KERNEL);
|
||||
if (dire == NULL) {
|
||||
ERROR("Failed to allocate squashfs_dir_entry\n");
|
||||
goto finish;
|
||||
}
|
||||
|
||||
/*
|
||||
* Return "." and ".." entries as the first two filenames in the
|
||||
* directory. To maximise compression these two entries are not
|
||||
* stored in the directory, and so we invent them here.
|
||||
*
|
||||
* It also means that the external f_pos is offset by 3 from the
|
||||
* on-disk directory f_pos.
|
||||
*/
|
||||
while (file->f_pos < 3) {
|
||||
char *name;
|
||||
int i_ino;
|
||||
|
||||
if (file->f_pos == 0) {
|
||||
name = ".";
|
||||
size = 1;
|
||||
i_ino = inode->i_ino;
|
||||
} else {
|
||||
name = "..";
|
||||
size = 2;
|
||||
i_ino = squashfs_i(inode)->parent;
|
||||
}
|
||||
|
||||
TRACE("Calling filldir(%p, %s, %d, %lld, %d, %d)\n",
|
||||
dirent, name, size, file->f_pos, i_ino,
|
||||
squashfs_filetype_table[1]);
|
||||
|
||||
if (filldir(dirent, name, size, file->f_pos, i_ino,
|
||||
squashfs_filetype_table[1]) < 0) {
|
||||
TRACE("Filldir returned less than 0\n");
|
||||
goto finish;
|
||||
}
|
||||
|
||||
file->f_pos += size;
|
||||
}
|
||||
|
||||
length = get_dir_index_using_offset(inode->i_sb, &block, &offset,
|
||||
squashfs_i(inode)->dir_idx_start,
|
||||
squashfs_i(inode)->dir_idx_offset,
|
||||
squashfs_i(inode)->dir_idx_cnt,
|
||||
file->f_pos);
|
||||
|
||||
while (length < i_size_read(inode)) {
|
||||
/*
|
||||
* Read directory header
|
||||
*/
|
||||
err = squashfs_read_metadata(inode->i_sb, &dirh, &block,
|
||||
&offset, sizeof(dirh));
|
||||
if (err < 0)
|
||||
goto failed_read;
|
||||
|
||||
length += sizeof(dirh);
|
||||
|
||||
dir_count = le32_to_cpu(dirh.count) + 1;
|
||||
while (dir_count--) {
|
||||
/*
|
||||
* Read directory entry.
|
||||
*/
|
||||
err = squashfs_read_metadata(inode->i_sb, dire, &block,
|
||||
&offset, sizeof(*dire));
|
||||
if (err < 0)
|
||||
goto failed_read;
|
||||
|
||||
size = le16_to_cpu(dire->size) + 1;
|
||||
|
||||
err = squashfs_read_metadata(inode->i_sb, dire->name,
|
||||
&block, &offset, size);
|
||||
if (err < 0)
|
||||
goto failed_read;
|
||||
|
||||
length += sizeof(*dire) + size;
|
||||
|
||||
if (file->f_pos >= length)
|
||||
continue;
|
||||
|
||||
dire->name[size] = '\0';
|
||||
inode_number = le32_to_cpu(dirh.inode_number) +
|
||||
((short) le16_to_cpu(dire->inode_number));
|
||||
type = le16_to_cpu(dire->type);
|
||||
|
||||
TRACE("Calling filldir(%p, %s, %d, %lld, %x:%x, %d, %d)"
|
||||
"\n", dirent, dire->name, size,
|
||||
file->f_pos,
|
||||
le32_to_cpu(dirh.start_block),
|
||||
le16_to_cpu(dire->offset),
|
||||
inode_number,
|
||||
squashfs_filetype_table[type]);
|
||||
|
||||
if (filldir(dirent, dire->name, size, file->f_pos,
|
||||
inode_number,
|
||||
squashfs_filetype_table[type]) < 0) {
|
||||
TRACE("Filldir returned less than 0\n");
|
||||
goto finish;
|
||||
}
|
||||
|
||||
file->f_pos = length;
|
||||
}
|
||||
}
|
||||
|
||||
finish:
|
||||
kfree(dire);
|
||||
return 0;
|
||||
|
||||
failed_read:
|
||||
ERROR("Unable to read directory block [%llx:%x]\n", block, offset);
|
||||
kfree(dire);
|
||||
return 0;
|
||||
}
|
||||
|
||||
|
||||
const struct file_operations squashfs_dir_ops = {
|
||||
.read = generic_read_dir,
|
||||
.readdir = squashfs_readdir
|
||||
};
|
||||
|
|
@ -0,0 +1,155 @@
|
|||
/*
|
||||
* Squashfs - a compressed read only filesystem for Linux
|
||||
*
|
||||
* Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008
|
||||
* Phillip Lougher <phillip@lougher.demon.co.uk>
|
||||
*
|
||||
* This program is free software; you can redistribute it and/or
|
||||
* modify it under the terms of the GNU General Public License
|
||||
* as published by the Free Software Foundation; either version 2,
|
||||
* or (at your option) any later version.
|
||||
*
|
||||
* This program is distributed in the hope that it will be useful,
|
||||
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||||
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
||||
* GNU General Public License for more details.
|
||||
*
|
||||
* You should have received a copy of the GNU General Public License
|
||||
* along with this program; if not, write to the Free Software
|
||||
* Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
|
||||
*
|
||||
* export.c
|
||||
*/
|
||||
|
||||
/*
|
||||
* This file implements code to make Squashfs filesystems exportable (NFS etc.)
|
||||
*
|
||||
* The export code uses an inode lookup table to map inode numbers passed in
|
||||
* filehandles to an inode location on disk. This table is stored compressed
|
||||
* into metadata blocks. A second index table is used to locate these. This
|
||||
* second index table for speed of access (and because it is small) is read at
|
||||
* mount time and cached in memory.
|
||||
*
|
||||
* The inode lookup table is used only by the export code, inode disk
|
||||
* locations are directly encoded in directories, enabling direct access
|
||||
* without an intermediate lookup for all operations except the export ops.
|
||||
*/
|
||||
|
||||
#include <linux/fs.h>
|
||||
#include <linux/vfs.h>
|
||||
#include <linux/dcache.h>
|
||||
#include <linux/exportfs.h>
|
||||
#include <linux/zlib.h>
|
||||
|
||||
#include "squashfs_fs.h"
|
||||
#include "squashfs_fs_sb.h"
|
||||
#include "squashfs_fs_i.h"
|
||||
#include "squashfs.h"
|
||||
|
||||
/*
|
||||
* Look-up inode number (ino) in table, returning the inode location.
|
||||
*/
|
||||
static long long squashfs_inode_lookup(struct super_block *sb, int ino_num)
|
||||
{
|
||||
struct squashfs_sb_info *msblk = sb->s_fs_info;
|
||||
int blk = SQUASHFS_LOOKUP_BLOCK(ino_num - 1);
|
||||
int offset = SQUASHFS_LOOKUP_BLOCK_OFFSET(ino_num - 1);
|
||||
u64 start = le64_to_cpu(msblk->inode_lookup_table[blk]);
|
||||
__le64 ino;
|
||||
int err;
|
||||
|
||||
TRACE("Entered squashfs_inode_lookup, inode_number = %d\n", ino_num);
|
||||
|
||||
err = squashfs_read_metadata(sb, &ino, &start, &offset, sizeof(ino));
|
||||
if (err < 0)
|
||||
return err;
|
||||
|
||||
TRACE("squashfs_inode_lookup, inode = 0x%llx\n",
|
||||
(u64) le64_to_cpu(ino));
|
||||
|
||||
return le64_to_cpu(ino);
|
||||
}
|
||||
|
||||
|
||||
static struct dentry *squashfs_export_iget(struct super_block *sb,
|
||||
unsigned int ino_num)
|
||||
{
|
||||
long long ino;
|
||||
struct dentry *dentry = ERR_PTR(-ENOENT);
|
||||
|
||||
TRACE("Entered squashfs_export_iget\n");
|
||||
|
||||
ino = squashfs_inode_lookup(sb, ino_num);
|
||||
if (ino >= 0)
|
||||
dentry = d_obtain_alias(squashfs_iget(sb, ino, ino_num));
|
||||
|
||||
return dentry;
|
||||
}
|
||||
|
||||
|
||||
static struct dentry *squashfs_fh_to_dentry(struct super_block *sb,
|
||||
struct fid *fid, int fh_len, int fh_type)
|
||||
{
|
||||
if ((fh_type != FILEID_INO32_GEN && fh_type != FILEID_INO32_GEN_PARENT)
|
||||
|| fh_len < 2)
|
||||
return NULL;
|
||||
|
||||
return squashfs_export_iget(sb, fid->i32.ino);
|
||||
}
|
||||
|
||||
|
||||
static struct dentry *squashfs_fh_to_parent(struct super_block *sb,
|
||||
struct fid *fid, int fh_len, int fh_type)
|
||||
{
|
||||
if (fh_type != FILEID_INO32_GEN_PARENT || fh_len < 4)
|
||||
return NULL;
|
||||
|
||||
return squashfs_export_iget(sb, fid->i32.parent_ino);
|
||||
}
|
||||
|
||||
|
||||
static struct dentry *squashfs_get_parent(struct dentry *child)
|
||||
{
|
||||
struct inode *inode = child->d_inode;
|
||||
unsigned int parent_ino = squashfs_i(inode)->parent;
|
||||
|
||||
return squashfs_export_iget(inode->i_sb, parent_ino);
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
* Read uncompressed inode lookup table indexes off disk into memory
|
||||
*/
|
||||
__le64 *squashfs_read_inode_lookup_table(struct super_block *sb,
|
||||
u64 lookup_table_start, unsigned int inodes)
|
||||
{
|
||||
unsigned int length = SQUASHFS_LOOKUP_BLOCK_BYTES(inodes);
|
||||
__le64 *inode_lookup_table;
|
||||
int err;
|
||||
|
||||
TRACE("In read_inode_lookup_table, length %d\n", length);
|
||||
|
||||
/* Allocate inode lookup table indexes */
|
||||
inode_lookup_table = kmalloc(length, GFP_KERNEL);
|
||||
if (inode_lookup_table == NULL) {
|
||||
ERROR("Failed to allocate inode lookup table\n");
|
||||
return ERR_PTR(-ENOMEM);
|
||||
}
|
||||
|
||||
err = squashfs_read_table(sb, inode_lookup_table, lookup_table_start,
|
||||
length);
|
||||
if (err < 0) {
|
||||
ERROR("unable to read inode lookup table\n");
|
||||
kfree(inode_lookup_table);
|
||||
return ERR_PTR(err);
|
||||
}
|
||||
|
||||
return inode_lookup_table;
|
||||
}
|
||||
|
||||
|
||||
const struct export_operations squashfs_export_ops = {
|
||||
.fh_to_dentry = squashfs_fh_to_dentry,
|
||||
.fh_to_parent = squashfs_fh_to_parent,
|
||||
.get_parent = squashfs_get_parent
|
||||
};
|
||||
|
|
@ -0,0 +1,502 @@
|
|||
/*
|
||||
* Squashfs - a compressed read only filesystem for Linux
|
||||
*
|
||||
* Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008
|
||||
* Phillip Lougher <phillip@lougher.demon.co.uk>
|
||||
*
|
||||
* This program is free software; you can redistribute it and/or
|
||||
* modify it under the terms of the GNU General Public License
|
||||
* as published by the Free Software Foundation; either version 2,
|
||||
* or (at your option) any later version.
|
||||
*
|
||||
* This program is distributed in the hope that it will be useful,
|
||||
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||||
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
||||
* GNU General Public License for more details.
|
||||
*
|
||||
* You should have received a copy of the GNU General Public License
|
||||
* along with this program; if not, write to the Free Software
|
||||
* Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
|
||||
*
|
||||
* file.c
|
||||
*/
|
||||
|
||||
/*
|
||||
* This file contains code for handling regular files. A regular file
|
||||
* consists of a sequence of contiguous compressed blocks, and/or a
|
||||
* compressed fragment block (tail-end packed block). The compressed size
|
||||
* of each datablock is stored in a block list contained within the
|
||||
* file inode (itself stored in one or more compressed metadata blocks).
|
||||
*
|
||||
* To speed up access to datablocks when reading 'large' files (256 Mbytes or
|
||||
* larger), the code implements an index cache that caches the mapping from
|
||||
* block index to datablock location on disk.
|
||||
*
|
||||
* The index cache allows Squashfs to handle large files (up to 1.75 TiB) while
|
||||
* retaining a simple and space-efficient block list on disk. The cache
|
||||
* is split into slots, caching up to eight 224 GiB files (128 KiB blocks).
|
||||
* Larger files use multiple slots, with 1.75 TiB files using all 8 slots.
|
||||
* The index cache is designed to be memory efficient, and by default uses
|
||||
* 16 KiB.
|
||||
*/
|
||||
|
||||
#include <linux/fs.h>
|
||||
#include <linux/vfs.h>
|
||||
#include <linux/kernel.h>
|
||||
#include <linux/slab.h>
|
||||
#include <linux/string.h>
|
||||
#include <linux/pagemap.h>
|
||||
#include <linux/mutex.h>
|
||||
#include <linux/zlib.h>
|
||||
|
||||
#include "squashfs_fs.h"
|
||||
#include "squashfs_fs_sb.h"
|
||||
#include "squashfs_fs_i.h"
|
||||
#include "squashfs.h"
|
||||
|
||||
/*
|
||||
* Locate cache slot in range [offset, index] for specified inode. If
|
||||
* there's more than one return the slot closest to index.
|
||||
*/
|
||||
static struct meta_index *locate_meta_index(struct inode *inode, int offset,
|
||||
int index)
|
||||
{
|
||||
struct meta_index *meta = NULL;
|
||||
struct squashfs_sb_info *msblk = inode->i_sb->s_fs_info;
|
||||
int i;
|
||||
|
||||
mutex_lock(&msblk->meta_index_mutex);
|
||||
|
||||
TRACE("locate_meta_index: index %d, offset %d\n", index, offset);
|
||||
|
||||
if (msblk->meta_index == NULL)
|
||||
goto not_allocated;
|
||||
|
||||
for (i = 0; i < SQUASHFS_META_SLOTS; i++) {
|
||||
if (msblk->meta_index[i].inode_number == inode->i_ino &&
|
||||
msblk->meta_index[i].offset >= offset &&
|
||||
msblk->meta_index[i].offset <= index &&
|
||||
msblk->meta_index[i].locked == 0) {
|
||||
TRACE("locate_meta_index: entry %d, offset %d\n", i,
|
||||
msblk->meta_index[i].offset);
|
||||
meta = &msblk->meta_index[i];
|
||||
offset = meta->offset;
|
||||
}
|
||||
}
|
||||
|
||||
if (meta)
|
||||
meta->locked = 1;
|
||||
|
||||
not_allocated:
|
||||
mutex_unlock(&msblk->meta_index_mutex);
|
||||
|
||||
return meta;
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
* Find and initialise an empty cache slot for index offset.
|
||||
*/
|
||||
static struct meta_index *empty_meta_index(struct inode *inode, int offset,
|
||||
int skip)
|
||||
{
|
||||
struct squashfs_sb_info *msblk = inode->i_sb->s_fs_info;
|
||||
struct meta_index *meta = NULL;
|
||||
int i;
|
||||
|
||||
mutex_lock(&msblk->meta_index_mutex);
|
||||
|
||||
TRACE("empty_meta_index: offset %d, skip %d\n", offset, skip);
|
||||
|
||||
if (msblk->meta_index == NULL) {
|
||||
/*
|
||||
* First time cache index has been used, allocate and
|
||||
* initialise. The cache index could be allocated at
|
||||
* mount time but doing it here means it is allocated only
|
||||
* if a 'large' file is read.
|
||||
*/
|
||||
msblk->meta_index = kcalloc(SQUASHFS_META_SLOTS,
|
||||
sizeof(*(msblk->meta_index)), GFP_KERNEL);
|
||||
if (msblk->meta_index == NULL) {
|
||||
ERROR("Failed to allocate meta_index\n");
|
||||
goto failed;
|
||||
}
|
||||
for (i = 0; i < SQUASHFS_META_SLOTS; i++) {
|
||||
msblk->meta_index[i].inode_number = 0;
|
||||
msblk->meta_index[i].locked = 0;
|
||||
}
|
||||
msblk->next_meta_index = 0;
|
||||
}
|
||||
|
||||
for (i = SQUASHFS_META_SLOTS; i &&
|
||||
msblk->meta_index[msblk->next_meta_index].locked; i--)
|
||||
msblk->next_meta_index = (msblk->next_meta_index + 1) %
|
||||
SQUASHFS_META_SLOTS;
|
||||
|
||||
if (i == 0) {
|
||||
TRACE("empty_meta_index: failed!\n");
|
||||
goto failed;
|
||||
}
|
||||
|
||||
TRACE("empty_meta_index: returned meta entry %d, %p\n",
|
||||
msblk->next_meta_index,
|
||||
&msblk->meta_index[msblk->next_meta_index]);
|
||||
|
||||
meta = &msblk->meta_index[msblk->next_meta_index];
|
||||
msblk->next_meta_index = (msblk->next_meta_index + 1) %
|
||||
SQUASHFS_META_SLOTS;
|
||||
|
||||
meta->inode_number = inode->i_ino;
|
||||
meta->offset = offset;
|
||||
meta->skip = skip;
|
||||
meta->entries = 0;
|
||||
meta->locked = 1;
|
||||
|
||||
failed:
|
||||
mutex_unlock(&msblk->meta_index_mutex);
|
||||
return meta;
|
||||
}
|
||||
|
||||
|
||||
static void release_meta_index(struct inode *inode, struct meta_index *meta)
|
||||
{
|
||||
struct squashfs_sb_info *msblk = inode->i_sb->s_fs_info;
|
||||
mutex_lock(&msblk->meta_index_mutex);
|
||||
meta->locked = 0;
|
||||
mutex_unlock(&msblk->meta_index_mutex);
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
* Read the next n blocks from the block list, starting from
|
||||
* metadata block <start_block, offset>.
|
||||
*/
|
||||
static long long read_indexes(struct super_block *sb, int n,
|
||||
u64 *start_block, int *offset)
|
||||
{
|
||||
int err, i;
|
||||
long long block = 0;
|
||||
__le32 *blist = kmalloc(PAGE_CACHE_SIZE, GFP_KERNEL);
|
||||
|
||||
if (blist == NULL) {
|
||||
ERROR("read_indexes: Failed to allocate block_list\n");
|
||||
return -ENOMEM;
|
||||
}
|
||||
|
||||
while (n) {
|
||||
int blocks = min_t(int, n, PAGE_CACHE_SIZE >> 2);
|
||||
|
||||
err = squashfs_read_metadata(sb, blist, start_block,
|
||||
offset, blocks << 2);
|
||||
if (err < 0) {
|
||||
ERROR("read_indexes: reading block [%llx:%x]\n",
|
||||
*start_block, *offset);
|
||||
goto failure;
|
||||
}
|
||||
|
||||
for (i = 0; i < blocks; i++) {
|
||||
int size = le32_to_cpu(blist[i]);
|
||||
block += SQUASHFS_COMPRESSED_SIZE_BLOCK(size);
|
||||
}
|
||||
n -= blocks;
|
||||
}
|
||||
|
||||
kfree(blist);
|
||||
return block;
|
||||
|
||||
failure:
|
||||
kfree(blist);
|
||||
return err;
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
* Each cache index slot has SQUASHFS_META_ENTRIES, each of which
|
||||
* can cache one index -> datablock/blocklist-block mapping. We wish
|
||||
* to distribute these over the length of the file, entry[0] maps index x,
|
||||
* entry[1] maps index x + skip, entry[2] maps index x + 2 * skip, and so on.
|
||||
* The larger the file, the greater the skip factor. The skip factor is
|
||||
* limited to the size of the metadata cache (SQUASHFS_CACHED_BLKS) to ensure
|
||||
* the number of metadata blocks that need to be read fits into the cache.
|
||||
* If the skip factor is limited in this way then the file will use multiple
|
||||
* slots.
|
||||
*/
|
||||
static inline int calculate_skip(int blocks)
|
||||
{
|
||||
int skip = blocks / ((SQUASHFS_META_ENTRIES + 1)
|
||||
* SQUASHFS_META_INDEXES);
|
||||
return min(SQUASHFS_CACHED_BLKS - 1, skip + 1);
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
* Search and grow the index cache for the specified inode, returning the
|
||||
* on-disk locations of the datablock and block list metadata block
|
||||
* <index_block, index_offset> for index (scaled to nearest cache index).
|
||||
*/
|
||||
static int fill_meta_index(struct inode *inode, int index,
|
||||
u64 *index_block, int *index_offset, u64 *data_block)
|
||||
{
|
||||
struct squashfs_sb_info *msblk = inode->i_sb->s_fs_info;
|
||||
int skip = calculate_skip(i_size_read(inode) >> msblk->block_log);
|
||||
int offset = 0;
|
||||
struct meta_index *meta;
|
||||
struct meta_entry *meta_entry;
|
||||
u64 cur_index_block = squashfs_i(inode)->block_list_start;
|
||||
int cur_offset = squashfs_i(inode)->offset;
|
||||
u64 cur_data_block = squashfs_i(inode)->start;
|
||||
int err, i;
|
||||
|
||||
/*
|
||||
* Scale index to cache index (cache slot entry)
|
||||
*/
|
||||
index /= SQUASHFS_META_INDEXES * skip;
|
||||
|
||||
while (offset < index) {
|
||||
meta = locate_meta_index(inode, offset + 1, index);
|
||||
|
||||
if (meta == NULL) {
|
||||
meta = empty_meta_index(inode, offset + 1, skip);
|
||||
if (meta == NULL)
|
||||
goto all_done;
|
||||
} else {
|
||||
offset = index < meta->offset + meta->entries ? index :
|
||||
meta->offset + meta->entries - 1;
|
||||
meta_entry = &meta->meta_entry[offset - meta->offset];
|
||||
cur_index_block = meta_entry->index_block +
|
||||
msblk->inode_table;
|
||||
cur_offset = meta_entry->offset;
|
||||
cur_data_block = meta_entry->data_block;
|
||||
TRACE("get_meta_index: offset %d, meta->offset %d, "
|
||||
"meta->entries %d\n", offset, meta->offset,
|
||||
meta->entries);
|
||||
TRACE("get_meta_index: index_block 0x%llx, offset 0x%x"
|
||||
" data_block 0x%llx\n", cur_index_block,
|
||||
cur_offset, cur_data_block);
|
||||
}
|
||||
|
||||
/*
|
||||
* If necessary grow cache slot by reading block list. Cache
|
||||
* slot is extended up to index or to the end of the slot, in
|
||||
* which case further slots will be used.
|
||||
*/
|
||||
for (i = meta->offset + meta->entries; i <= index &&
|
||||
i < meta->offset + SQUASHFS_META_ENTRIES; i++) {
|
||||
int blocks = skip * SQUASHFS_META_INDEXES;
|
||||
long long res = read_indexes(inode->i_sb, blocks,
|
||||
&cur_index_block, &cur_offset);
|
||||
|
||||
if (res < 0) {
|
||||
if (meta->entries == 0)
|
||||
/*
|
||||
* Don't leave an empty slot on read
|
||||
* error allocated to this inode...
|
||||
*/
|
||||
meta->inode_number = 0;
|
||||
err = res;
|
||||
goto failed;
|
||||
}
|
||||
|
||||
cur_data_block += res;
|
||||
meta_entry = &meta->meta_entry[i - meta->offset];
|
||||
meta_entry->index_block = cur_index_block -
|
||||
msblk->inode_table;
|
||||
meta_entry->offset = cur_offset;
|
||||
meta_entry->data_block = cur_data_block;
|
||||
meta->entries++;
|
||||
offset++;
|
||||
}
|
||||
|
||||
TRACE("get_meta_index: meta->offset %d, meta->entries %d\n",
|
||||
meta->offset, meta->entries);
|
||||
|
||||
release_meta_index(inode, meta);
|
||||
}
|
||||
|
||||
all_done:
|
||||
*index_block = cur_index_block;
|
||||
*index_offset = cur_offset;
|
||||
*data_block = cur_data_block;
|
||||
|
||||
/*
|
||||
* Scale cache index (cache slot entry) to index
|
||||
*/
|
||||
return offset * SQUASHFS_META_INDEXES * skip;
|
||||
|
||||
failed:
|
||||
release_meta_index(inode, meta);
|
||||
return err;
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
* Get the on-disk location and compressed size of the datablock
|
||||
* specified by index. Fill_meta_index() does most of the work.
|
||||
*/
|
||||
static int read_blocklist(struct inode *inode, int index, u64 *block)
|
||||
{
|
||||
u64 start;
|
||||
long long blks;
|
||||
int offset;
|
||||
__le32 size;
|
||||
int res = fill_meta_index(inode, index, &start, &offset, block);
|
||||
|
||||
TRACE("read_blocklist: res %d, index %d, start 0x%llx, offset"
|
||||
" 0x%x, block 0x%llx\n", res, index, start, offset,
|
||||
*block);
|
||||
|
||||
if (res < 0)
|
||||
return res;
|
||||
|
||||
/*
|
||||
* res contains the index of the mapping returned by fill_meta_index(),
|
||||
* this will likely be less than the desired index (because the
|
||||
* meta_index cache works at a higher granularity). Read any
|
||||
* extra block indexes needed.
|
||||
*/
|
||||
if (res < index) {
|
||||
blks = read_indexes(inode->i_sb, index - res, &start, &offset);
|
||||
if (blks < 0)
|
||||
return (int) blks;
|
||||
*block += blks;
|
||||
}
|
||||
|
||||
/*
|
||||
* Read length of block specified by index.
|
||||
*/
|
||||
res = squashfs_read_metadata(inode->i_sb, &size, &start, &offset,
|
||||
sizeof(size));
|
||||
if (res < 0)
|
||||
return res;
|
||||
return le32_to_cpu(size);
|
||||
}
|
||||
|
||||
|
||||
static int squashfs_readpage(struct file *file, struct page *page)
|
||||
{
|
||||
struct inode *inode = page->mapping->host;
|
||||
struct squashfs_sb_info *msblk = inode->i_sb->s_fs_info;
|
||||
int bytes, i, offset = 0, sparse = 0;
|
||||
struct squashfs_cache_entry *buffer = NULL;
|
||||
void *pageaddr;
|
||||
|
||||
int mask = (1 << (msblk->block_log - PAGE_CACHE_SHIFT)) - 1;
|
||||
int index = page->index >> (msblk->block_log - PAGE_CACHE_SHIFT);
|
||||
int start_index = page->index & ~mask;
|
||||
int end_index = start_index | mask;
|
||||
int file_end = i_size_read(inode) >> msblk->block_log;
|
||||
|
||||
TRACE("Entered squashfs_readpage, page index %lx, start block %llx\n",
|
||||
page->index, squashfs_i(inode)->start);
|
||||
|
||||
if (page->index >= ((i_size_read(inode) + PAGE_CACHE_SIZE - 1) >>
|
||||
PAGE_CACHE_SHIFT))
|
||||
goto out;
|
||||
|
||||
if (index < file_end || squashfs_i(inode)->fragment_block ==
|
||||
SQUASHFS_INVALID_BLK) {
|
||||
/*
|
||||
* Reading a datablock from disk. Need to read block list
|
||||
* to get location and block size.
|
||||
*/
|
||||
u64 block = 0;
|
||||
int bsize = read_blocklist(inode, index, &block);
|
||||
if (bsize < 0)
|
||||
goto error_out;
|
||||
|
||||
if (bsize == 0) { /* hole */
|
||||
bytes = index == file_end ?
|
||||
(i_size_read(inode) & (msblk->block_size - 1)) :
|
||||
msblk->block_size;
|
||||
sparse = 1;
|
||||
} else {
|
||||
/*
|
||||
* Read and decompress datablock.
|
||||
*/
|
||||
buffer = squashfs_get_datablock(inode->i_sb,
|
||||
block, bsize);
|
||||
if (buffer->error) {
|
||||
ERROR("Unable to read page, block %llx, size %x"
|
||||
"\n", block, bsize);
|
||||
squashfs_cache_put(buffer);
|
||||
goto error_out;
|
||||
}
|
||||
bytes = buffer->length;
|
||||
}
|
||||
} else {
|
||||
/*
|
||||
* Datablock is stored inside a fragment (tail-end packed
|
||||
* block).
|
||||
*/
|
||||
buffer = squashfs_get_fragment(inode->i_sb,
|
||||
squashfs_i(inode)->fragment_block,
|
||||
squashfs_i(inode)->fragment_size);
|
||||
|
||||
if (buffer->error) {
|
||||
ERROR("Unable to read page, block %llx, size %x\n",
|
||||
squashfs_i(inode)->fragment_block,
|
||||
squashfs_i(inode)->fragment_size);
|
||||
squashfs_cache_put(buffer);
|
||||
goto error_out;
|
||||
}
|
||||
bytes = i_size_read(inode) & (msblk->block_size - 1);
|
||||
offset = squashfs_i(inode)->fragment_offset;
|
||||
}
|
||||
|
||||
/*
|
||||
* Loop copying datablock into pages. As the datablock likely covers
|
||||
* many PAGE_CACHE_SIZE pages (default block size is 128 KiB) explicitly
|
||||
* grab the pages from the page cache, except for the page that we've
|
||||
* been called to fill.
|
||||
*/
|
||||
for (i = start_index; i <= end_index && bytes > 0; i++,
|
||||
bytes -= PAGE_CACHE_SIZE, offset += PAGE_CACHE_SIZE) {
|
||||
struct page *push_page;
|
||||
int avail = sparse ? 0 : min_t(int, bytes, PAGE_CACHE_SIZE);
|
||||
|
||||
TRACE("bytes %d, i %d, available_bytes %d\n", bytes, i, avail);
|
||||
|
||||
push_page = (i == page->index) ? page :
|
||||
grab_cache_page_nowait(page->mapping, i);
|
||||
|
||||
if (!push_page)
|
||||
continue;
|
||||
|
||||
if (PageUptodate(push_page))
|
||||
goto skip_page;
|
||||
|
||||
pageaddr = kmap_atomic(push_page, KM_USER0);
|
||||
squashfs_copy_data(pageaddr, buffer, offset, avail);
|
||||
memset(pageaddr + avail, 0, PAGE_CACHE_SIZE - avail);
|
||||
kunmap_atomic(pageaddr, KM_USER0);
|
||||
flush_dcache_page(push_page);
|
||||
SetPageUptodate(push_page);
|
||||
skip_page:
|
||||
unlock_page(push_page);
|
||||
if (i != page->index)
|
||||
page_cache_release(push_page);
|
||||
}
|
||||
|
||||
if (!sparse)
|
||||
squashfs_cache_put(buffer);
|
||||
|
||||
return 0;
|
||||
|
||||
error_out:
|
||||
SetPageError(page);
|
||||
out:
|
||||
pageaddr = kmap_atomic(page, KM_USER0);
|
||||
memset(pageaddr, 0, PAGE_CACHE_SIZE);
|
||||
kunmap_atomic(pageaddr, KM_USER0);
|
||||
flush_dcache_page(page);
|
||||
if (!PageError(page))
|
||||
SetPageUptodate(page);
|
||||
unlock_page(page);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
|
||||
const struct address_space_operations squashfs_aops = {
|
||||
.readpage = squashfs_readpage
|
||||
};
|
||||
|
|
@ -0,0 +1,98 @@
|
|||
/*
|
||||
* Squashfs - a compressed read only filesystem for Linux
|
||||
*
|
||||
* Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008
|
||||
* Phillip Lougher <phillip@lougher.demon.co.uk>
|
||||
*
|
||||
* This program is free software; you can redistribute it and/or
|
||||
* modify it under the terms of the GNU General Public License
|
||||
* as published by the Free Software Foundation; either version 2,
|
||||
* or (at your option) any later version.
|
||||
*
|
||||
* This program is distributed in the hope that it will be useful,
|
||||
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||||
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
||||
* GNU General Public License for more details.
|
||||
*
|
||||
* You should have received a copy of the GNU General Public License
|
||||
* along with this program; if not, write to the Free Software
|
||||
* Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
|
||||
*
|
||||
* fragment.c
|
||||
*/
|
||||
|
||||
/*
|
||||
* This file implements code to handle compressed fragments (tail-end packed
|
||||
* datablocks).
|
||||
*
|
||||
* Regular files contain a fragment index which is mapped to a fragment
|
||||
* location on disk and compressed size using a fragment lookup table.
|
||||
* Like everything in Squashfs this fragment lookup table is itself stored
|
||||
* compressed into metadata blocks. A second index table is used to locate
|
||||
* these. This second index table for speed of access (and because it
|
||||
* is small) is read at mount time and cached in memory.
|
||||
*/
|
||||
|
||||
#include <linux/fs.h>
|
||||
#include <linux/vfs.h>
|
||||
#include <linux/slab.h>
|
||||
#include <linux/zlib.h>
|
||||
|
||||
#include "squashfs_fs.h"
|
||||
#include "squashfs_fs_sb.h"
|
||||
#include "squashfs_fs_i.h"
|
||||
#include "squashfs.h"
|
||||
|
||||
/*
|
||||
* Look-up fragment using the fragment index table. Return the on disk
|
||||
* location of the fragment and its compressed size
|
||||
*/
|
||||
int squashfs_frag_lookup(struct super_block *sb, unsigned int fragment,
|
||||
u64 *fragment_block)
|
||||
{
|
||||
struct squashfs_sb_info *msblk = sb->s_fs_info;
|
||||
int block = SQUASHFS_FRAGMENT_INDEX(fragment);
|
||||
int offset = SQUASHFS_FRAGMENT_INDEX_OFFSET(fragment);
|
||||
u64 start_block = le64_to_cpu(msblk->fragment_index[block]);
|
||||
struct squashfs_fragment_entry fragment_entry;
|
||||
int size;
|
||||
|
||||
size = squashfs_read_metadata(sb, &fragment_entry, &start_block,
|
||||
&offset, sizeof(fragment_entry));
|
||||
if (size < 0)
|
||||
return size;
|
||||
|
||||
*fragment_block = le64_to_cpu(fragment_entry.start_block);
|
||||
size = le32_to_cpu(fragment_entry.size);
|
||||
|
||||
return size;
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
* Read the uncompressed fragment lookup table indexes off disk into memory
|
||||
*/
|
||||
__le64 *squashfs_read_fragment_index_table(struct super_block *sb,
|
||||
u64 fragment_table_start, unsigned int fragments)
|
||||
{
|
||||
unsigned int length = SQUASHFS_FRAGMENT_INDEX_BYTES(fragments);
|
||||
__le64 *fragment_index;
|
||||
int err;
|
||||
|
||||
/* Allocate fragment lookup table indexes */
|
||||
fragment_index = kmalloc(length, GFP_KERNEL);
|
||||
if (fragment_index == NULL) {
|
||||
ERROR("Failed to allocate fragment index table\n");
|
||||
return ERR_PTR(-ENOMEM);
|
||||
}
|
||||
|
||||
err = squashfs_read_table(sb, fragment_index, fragment_table_start,
|
||||
length);
|
||||
if (err < 0) {
|
||||
ERROR("unable to read fragment index table\n");
|
||||
kfree(fragment_index);
|
||||
return ERR_PTR(err);
|
||||
}
|
||||
|
||||
return fragment_index;
|
||||
}
|
||||
|
|
@ -0,0 +1,94 @@
|
|||
/*
|
||||
* Squashfs - a compressed read only filesystem for Linux
|
||||
*
|
||||
* Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008
|
||||
* Phillip Lougher <phillip@lougher.demon.co.uk>
|
||||
*
|
||||
* This program is free software; you can redistribute it and/or
|
||||
* modify it under the terms of the GNU General Public License
|
||||
* as published by the Free Software Foundation; either version 2,
|
||||
* or (at your option) any later version.
|
||||
*
|
||||
* This program is distributed in the hope that it will be useful,
|
||||
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||||
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
||||
* GNU General Public License for more details.
|
||||
*
|
||||
* You should have received a copy of the GNU General Public License
|
||||
* along with this program; if not, write to the Free Software
|
||||
* Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
|
||||
*
|
||||
* id.c
|
||||
*/
|
||||
|
||||
/*
|
||||
* This file implements code to handle uids and gids.
|
||||
*
|
||||
* For space efficiency regular files store uid and gid indexes, which are
|
||||
* converted to 32-bit uids/gids using an id look up table. This table is
|
||||
* stored compressed into metadata blocks. A second index table is used to
|
||||
* locate these. This second index table for speed of access (and because it
|
||||
* is small) is read at mount time and cached in memory.
|
||||
*/
|
||||
|
||||
#include <linux/fs.h>
|
||||
#include <linux/vfs.h>
|
||||
#include <linux/slab.h>
|
||||
#include <linux/zlib.h>
|
||||
|
||||
#include "squashfs_fs.h"
|
||||
#include "squashfs_fs_sb.h"
|
||||
#include "squashfs_fs_i.h"
|
||||
#include "squashfs.h"
|
||||
|
||||
/*
|
||||
* Map uid/gid index into real 32-bit uid/gid using the id look up table
|
||||
*/
|
||||
int squashfs_get_id(struct super_block *sb, unsigned int index,
|
||||
unsigned int *id)
|
||||
{
|
||||
struct squashfs_sb_info *msblk = sb->s_fs_info;
|
||||
int block = SQUASHFS_ID_BLOCK(index);
|
||||
int offset = SQUASHFS_ID_BLOCK_OFFSET(index);
|
||||
u64 start_block = le64_to_cpu(msblk->id_table[block]);
|
||||
__le32 disk_id;
|
||||
int err;
|
||||
|
||||
err = squashfs_read_metadata(sb, &disk_id, &start_block, &offset,
|
||||
sizeof(disk_id));
|
||||
if (err < 0)
|
||||
return err;
|
||||
|
||||
*id = le32_to_cpu(disk_id);
|
||||
return 0;
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
* Read uncompressed id lookup table indexes from disk into memory
|
||||
*/
|
||||
__le64 *squashfs_read_id_index_table(struct super_block *sb,
|
||||
u64 id_table_start, unsigned short no_ids)
|
||||
{
|
||||
unsigned int length = SQUASHFS_ID_BLOCK_BYTES(no_ids);
|
||||
__le64 *id_table;
|
||||
int err;
|
||||
|
||||
TRACE("In read_id_index_table, length %d\n", length);
|
||||
|
||||
/* Allocate id lookup table indexes */
|
||||
id_table = kmalloc(length, GFP_KERNEL);
|
||||
if (id_table == NULL) {
|
||||
ERROR("Failed to allocate id index table\n");
|
||||
return ERR_PTR(-ENOMEM);
|
||||
}
|
||||
|
||||
err = squashfs_read_table(sb, id_table, id_table_start, length);
|
||||
if (err < 0) {
|
||||
ERROR("unable to read id index table\n");
|
||||
kfree(id_table);
|
||||
return ERR_PTR(err);
|
||||
}
|
||||
|
||||
return id_table;
|
||||
}
|
||||
|
|
@ -0,0 +1,346 @@
|
|||
/*
|
||||
* Squashfs - a compressed read only filesystem for Linux
|
||||
*
|
||||
* Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008
|
||||
* Phillip Lougher <phillip@lougher.demon.co.uk>
|
||||
*
|
||||
* This program is free software; you can redistribute it and/or
|
||||
* modify it under the terms of the GNU General Public License
|
||||
* as published by the Free Software Foundation; either version 2,
|
||||
* or (at your option) any later version.
|
||||
*
|
||||
* This program is distributed in the hope that it will be useful,
|
||||
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||||
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
||||
* GNU General Public License for more details.
|
||||
*
|
||||
* You should have received a copy of the GNU General Public License
|
||||
* along with this program; if not, write to the Free Software
|
||||
* Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
|
||||
*
|
||||
* inode.c
|
||||
*/
|
||||
|
||||
/*
|
||||
* This file implements code to create and read inodes from disk.
|
||||
*
|
||||
* Inodes in Squashfs are identified by a 48-bit inode which encodes the
|
||||
* location of the compressed metadata block containing the inode, and the byte
|
||||
* offset into that block where the inode is placed (<block, offset>).
|
||||
*
|
||||
* To maximise compression there are different inodes for each file type
|
||||
* (regular file, directory, device, etc.), the inode contents and length
|
||||
* varying with the type.
|
||||
*
|
||||
* To further maximise compression, two types of regular file inode and
|
||||
* directory inode are defined: inodes optimised for frequently occurring
|
||||
* regular files and directories, and extended types where extra
|
||||
* information has to be stored.
|
||||
*/
|
||||
|
||||
#include <linux/fs.h>
|
||||
#include <linux/vfs.h>
|
||||
#include <linux/zlib.h>
|
||||
|
||||
#include "squashfs_fs.h"
|
||||
#include "squashfs_fs_sb.h"
|
||||
#include "squashfs_fs_i.h"
|
||||
#include "squashfs.h"
|
||||
|
||||
/*
|
||||
* Initialise VFS inode with the base inode information common to all
|
||||
* Squashfs inode types. Sqsh_ino contains the unswapped base inode
|
||||
* off disk.
|
||||
*/
|
||||
static int squashfs_new_inode(struct super_block *sb, struct inode *inode,
|
||||
struct squashfs_base_inode *sqsh_ino)
|
||||
{
|
||||
int err;
|
||||
|
||||
err = squashfs_get_id(sb, le16_to_cpu(sqsh_ino->uid), &inode->i_uid);
|
||||
if (err)
|
||||
return err;
|
||||
|
||||
err = squashfs_get_id(sb, le16_to_cpu(sqsh_ino->guid), &inode->i_gid);
|
||||
if (err)
|
||||
return err;
|
||||
|
||||
inode->i_ino = le32_to_cpu(sqsh_ino->inode_number);
|
||||
inode->i_mtime.tv_sec = le32_to_cpu(sqsh_ino->mtime);
|
||||
inode->i_atime.tv_sec = inode->i_mtime.tv_sec;
|
||||
inode->i_ctime.tv_sec = inode->i_mtime.tv_sec;
|
||||
inode->i_mode = le16_to_cpu(sqsh_ino->mode);
|
||||
inode->i_size = 0;
|
||||
|
||||
return err;
|
||||
}
|
||||
|
||||
|
||||
struct inode *squashfs_iget(struct super_block *sb, long long ino,
|
||||
unsigned int ino_number)
|
||||
{
|
||||
struct inode *inode = iget_locked(sb, ino_number);
|
||||
int err;
|
||||
|
||||
TRACE("Entered squashfs_iget\n");
|
||||
|
||||
if (!inode)
|
||||
return ERR_PTR(-ENOMEM);
|
||||
if (!(inode->i_state & I_NEW))
|
||||
return inode;
|
||||
|
||||
err = squashfs_read_inode(inode, ino);
|
||||
if (err) {
|
||||
iget_failed(inode);
|
||||
return ERR_PTR(err);
|
||||
}
|
||||
|
||||
unlock_new_inode(inode);
|
||||
return inode;
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
* Initialise VFS inode by reading inode from inode table (compressed
|
||||
* metadata). The format and amount of data read depends on type.
|
||||
*/
|
||||
int squashfs_read_inode(struct inode *inode, long long ino)
|
||||
{
|
||||
struct super_block *sb = inode->i_sb;
|
||||
struct squashfs_sb_info *msblk = sb->s_fs_info;
|
||||
u64 block = SQUASHFS_INODE_BLK(ino) + msblk->inode_table;
|
||||
int err, type, offset = SQUASHFS_INODE_OFFSET(ino);
|
||||
union squashfs_inode squashfs_ino;
|
||||
struct squashfs_base_inode *sqshb_ino = &squashfs_ino.base;
|
||||
|
||||
TRACE("Entered squashfs_read_inode\n");
|
||||
|
||||
/*
|
||||
* Read inode base common to all inode types.
|
||||
*/
|
||||
err = squashfs_read_metadata(sb, sqshb_ino, &block,
|
||||
&offset, sizeof(*sqshb_ino));
|
||||
if (err < 0)
|
||||
goto failed_read;
|
||||
|
||||
err = squashfs_new_inode(sb, inode, sqshb_ino);
|
||||
if (err)
|
||||
goto failed_read;
|
||||
|
||||
block = SQUASHFS_INODE_BLK(ino) + msblk->inode_table;
|
||||
offset = SQUASHFS_INODE_OFFSET(ino);
|
||||
|
||||
type = le16_to_cpu(sqshb_ino->inode_type);
|
||||
switch (type) {
|
||||
case SQUASHFS_REG_TYPE: {
|
||||
unsigned int frag_offset, frag_size, frag;
|
||||
u64 frag_blk;
|
||||
struct squashfs_reg_inode *sqsh_ino = &squashfs_ino.reg;
|
||||
|
||||
err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
|
||||
sizeof(*sqsh_ino));
|
||||
if (err < 0)
|
||||
goto failed_read;
|
||||
|
||||
frag = le32_to_cpu(sqsh_ino->fragment);
|
||||
if (frag != SQUASHFS_INVALID_FRAG) {
|
||||
frag_offset = le32_to_cpu(sqsh_ino->offset);
|
||||
frag_size = squashfs_frag_lookup(sb, frag, &frag_blk);
|
||||
if (frag_size < 0) {
|
||||
err = frag_size;
|
||||
goto failed_read;
|
||||
}
|
||||
} else {
|
||||
frag_blk = SQUASHFS_INVALID_BLK;
|
||||
frag_size = 0;
|
||||
frag_offset = 0;
|
||||
}
|
||||
|
||||
inode->i_nlink = 1;
|
||||
inode->i_size = le32_to_cpu(sqsh_ino->file_size);
|
||||
inode->i_fop = &generic_ro_fops;
|
||||
inode->i_mode |= S_IFREG;
|
||||
inode->i_blocks = ((inode->i_size - 1) >> 9) + 1;
|
||||
squashfs_i(inode)->fragment_block = frag_blk;
|
||||
squashfs_i(inode)->fragment_size = frag_size;
|
||||
squashfs_i(inode)->fragment_offset = frag_offset;
|
||||
squashfs_i(inode)->start = le32_to_cpu(sqsh_ino->start_block);
|
||||
squashfs_i(inode)->block_list_start = block;
|
||||
squashfs_i(inode)->offset = offset;
|
||||
inode->i_data.a_ops = &squashfs_aops;
|
||||
|
||||
TRACE("File inode %x:%x, start_block %llx, block_list_start "
|
||||
"%llx, offset %x\n", SQUASHFS_INODE_BLK(ino),
|
||||
offset, squashfs_i(inode)->start, block, offset);
|
||||
break;
|
||||
}
|
||||
case SQUASHFS_LREG_TYPE: {
|
||||
unsigned int frag_offset, frag_size, frag;
|
||||
u64 frag_blk;
|
||||
struct squashfs_lreg_inode *sqsh_ino = &squashfs_ino.lreg;
|
||||
|
||||
err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
|
||||
sizeof(*sqsh_ino));
|
||||
if (err < 0)
|
||||
goto failed_read;
|
||||
|
||||
frag = le32_to_cpu(sqsh_ino->fragment);
|
||||
if (frag != SQUASHFS_INVALID_FRAG) {
|
||||
frag_offset = le32_to_cpu(sqsh_ino->offset);
|
||||
frag_size = squashfs_frag_lookup(sb, frag, &frag_blk);
|
||||
if (frag_size < 0) {
|
||||
err = frag_size;
|
||||
goto failed_read;
|
||||
}
|
||||
} else {
|
||||
frag_blk = SQUASHFS_INVALID_BLK;
|
||||
frag_size = 0;
|
||||
frag_offset = 0;
|
||||
}
|
||||
|
||||
inode->i_nlink = le32_to_cpu(sqsh_ino->nlink);
|
||||
inode->i_size = le64_to_cpu(sqsh_ino->file_size);
|
||||
inode->i_fop = &generic_ro_fops;
|
||||
inode->i_mode |= S_IFREG;
|
||||
inode->i_blocks = ((inode->i_size -
|
||||
le64_to_cpu(sqsh_ino->sparse) - 1) >> 9) + 1;
|
||||
|
||||
squashfs_i(inode)->fragment_block = frag_blk;
|
||||
squashfs_i(inode)->fragment_size = frag_size;
|
||||
squashfs_i(inode)->fragment_offset = frag_offset;
|
||||
squashfs_i(inode)->start = le64_to_cpu(sqsh_ino->start_block);
|
||||
squashfs_i(inode)->block_list_start = block;
|
||||
squashfs_i(inode)->offset = offset;
|
||||
inode->i_data.a_ops = &squashfs_aops;
|
||||
|
||||
TRACE("File inode %x:%x, start_block %llx, block_list_start "
|
||||
"%llx, offset %x\n", SQUASHFS_INODE_BLK(ino),
|
||||
offset, squashfs_i(inode)->start, block, offset);
|
||||
break;
|
||||
}
|
||||
case SQUASHFS_DIR_TYPE: {
|
||||
struct squashfs_dir_inode *sqsh_ino = &squashfs_ino.dir;
|
||||
|
||||
err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
|
||||
sizeof(*sqsh_ino));
|
||||
if (err < 0)
|
||||
goto failed_read;
|
||||
|
||||
inode->i_nlink = le32_to_cpu(sqsh_ino->nlink);
|
||||
inode->i_size = le16_to_cpu(sqsh_ino->file_size);
|
||||
inode->i_op = &squashfs_dir_inode_ops;
|
||||
inode->i_fop = &squashfs_dir_ops;
|
||||
inode->i_mode |= S_IFDIR;
|
||||
squashfs_i(inode)->start = le32_to_cpu(sqsh_ino->start_block);
|
||||
squashfs_i(inode)->offset = le16_to_cpu(sqsh_ino->offset);
|
||||
squashfs_i(inode)->dir_idx_cnt = 0;
|
||||
squashfs_i(inode)->parent = le32_to_cpu(sqsh_ino->parent_inode);
|
||||
|
||||
TRACE("Directory inode %x:%x, start_block %llx, offset %x\n",
|
||||
SQUASHFS_INODE_BLK(ino), offset,
|
||||
squashfs_i(inode)->start,
|
||||
le16_to_cpu(sqsh_ino->offset));
|
||||
break;
|
||||
}
|
||||
case SQUASHFS_LDIR_TYPE: {
|
||||
struct squashfs_ldir_inode *sqsh_ino = &squashfs_ino.ldir;
|
||||
|
||||
err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
|
||||
sizeof(*sqsh_ino));
|
||||
if (err < 0)
|
||||
goto failed_read;
|
||||
|
||||
inode->i_nlink = le32_to_cpu(sqsh_ino->nlink);
|
||||
inode->i_size = le32_to_cpu(sqsh_ino->file_size);
|
||||
inode->i_op = &squashfs_dir_inode_ops;
|
||||
inode->i_fop = &squashfs_dir_ops;
|
||||
inode->i_mode |= S_IFDIR;
|
||||
squashfs_i(inode)->start = le32_to_cpu(sqsh_ino->start_block);
|
||||
squashfs_i(inode)->offset = le16_to_cpu(sqsh_ino->offset);
|
||||
squashfs_i(inode)->dir_idx_start = block;
|
||||
squashfs_i(inode)->dir_idx_offset = offset;
|
||||
squashfs_i(inode)->dir_idx_cnt = le16_to_cpu(sqsh_ino->i_count);
|
||||
squashfs_i(inode)->parent = le32_to_cpu(sqsh_ino->parent_inode);
|
||||
|
||||
TRACE("Long directory inode %x:%x, start_block %llx, offset "
|
||||
"%x\n", SQUASHFS_INODE_BLK(ino), offset,
|
||||
squashfs_i(inode)->start,
|
||||
le16_to_cpu(sqsh_ino->offset));
|
||||
break;
|
||||
}
|
||||
case SQUASHFS_SYMLINK_TYPE:
|
||||
case SQUASHFS_LSYMLINK_TYPE: {
|
||||
struct squashfs_symlink_inode *sqsh_ino = &squashfs_ino.symlink;
|
||||
|
||||
err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
|
||||
sizeof(*sqsh_ino));
|
||||
if (err < 0)
|
||||
goto failed_read;
|
||||
|
||||
inode->i_nlink = le32_to_cpu(sqsh_ino->nlink);
|
||||
inode->i_size = le32_to_cpu(sqsh_ino->symlink_size);
|
||||
inode->i_op = &page_symlink_inode_operations;
|
||||
inode->i_data.a_ops = &squashfs_symlink_aops;
|
||||
inode->i_mode |= S_IFLNK;
|
||||
squashfs_i(inode)->start = block;
|
||||
squashfs_i(inode)->offset = offset;
|
||||
|
||||
TRACE("Symbolic link inode %x:%x, start_block %llx, offset "
|
||||
"%x\n", SQUASHFS_INODE_BLK(ino), offset,
|
||||
block, offset);
|
||||
break;
|
||||
}
|
||||
case SQUASHFS_BLKDEV_TYPE:
|
||||
case SQUASHFS_CHRDEV_TYPE:
|
||||
case SQUASHFS_LBLKDEV_TYPE:
|
||||
case SQUASHFS_LCHRDEV_TYPE: {
|
||||
struct squashfs_dev_inode *sqsh_ino = &squashfs_ino.dev;
|
||||
unsigned int rdev;
|
||||
|
||||
err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
|
||||
sizeof(*sqsh_ino));
|
||||
if (err < 0)
|
||||
goto failed_read;
|
||||
|
||||
if (type == SQUASHFS_CHRDEV_TYPE)
|
||||
inode->i_mode |= S_IFCHR;
|
||||
else
|
||||
inode->i_mode |= S_IFBLK;
|
||||
inode->i_nlink = le32_to_cpu(sqsh_ino->nlink);
|
||||
rdev = le32_to_cpu(sqsh_ino->rdev);
|
||||
init_special_inode(inode, inode->i_mode, new_decode_dev(rdev));
|
||||
|
||||
TRACE("Device inode %x:%x, rdev %x\n",
|
||||
SQUASHFS_INODE_BLK(ino), offset, rdev);
|
||||
break;
|
||||
}
|
||||
case SQUASHFS_FIFO_TYPE:
|
||||
case SQUASHFS_SOCKET_TYPE:
|
||||
case SQUASHFS_LFIFO_TYPE:
|
||||
case SQUASHFS_LSOCKET_TYPE: {
|
||||
struct squashfs_ipc_inode *sqsh_ino = &squashfs_ino.ipc;
|
||||
|
||||
err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
|
||||
sizeof(*sqsh_ino));
|
||||
if (err < 0)
|
||||
goto failed_read;
|
||||
|
||||
if (type == SQUASHFS_FIFO_TYPE)
|
||||
inode->i_mode |= S_IFIFO;
|
||||
else
|
||||
inode->i_mode |= S_IFSOCK;
|
||||
inode->i_nlink = le32_to_cpu(sqsh_ino->nlink);
|
||||
init_special_inode(inode, inode->i_mode, 0);
|
||||
break;
|
||||
}
|
||||
default:
|
||||
ERROR("Unknown inode type %d in squashfs_iget!\n", type);
|
||||
return -EINVAL;
|
||||
}
|
||||
|
||||
return 0;
|
||||
|
||||
failed_read:
|
||||
ERROR("Unable to read inode 0x%llx\n", ino);
|
||||
return err;
|
||||
}
|
||||
|
|
@ -0,0 +1,242 @@
|
|||
/*
|
||||
* Squashfs - a compressed read only filesystem for Linux
|
||||
*
|
||||
* Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008
|
||||
* Phillip Lougher <phillip@lougher.demon.co.uk>
|
||||
*
|
||||
* This program is free software; you can redistribute it and/or
|
||||
* modify it under the terms of the GNU General Public License
|
||||
* as published by the Free Software Foundation; either version 2,
|
||||
* or (at your option) any later version.
|
||||
*
|
||||
* This program is distributed in the hope that it will be useful,
|
||||
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||||
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
||||
* GNU General Public License for more details.
|
||||
*
|
||||
* You should have received a copy of the GNU General Public License
|
||||
* along with this program; if not, write to the Free Software
|
||||
* Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
|
||||
*
|
||||
* namei.c
|
||||
*/
|
||||
|
||||
/*
|
||||
* This file implements code to do filename lookup in directories.
|
||||
*
|
||||
* Like inodes, directories are packed into compressed metadata blocks, stored
|
||||
* in a directory table. Directories are accessed using the start address of
|
||||
* the metablock containing the directory and the offset into the
|
||||
* decompressed block (<block, offset>).
|
||||
*
|
||||
* Directories are organised in a slightly complex way, and are not simply
|
||||
* a list of file names. The organisation takes advantage of the
|
||||
* fact that (in most cases) the inodes of the files will be in the same
|
||||
* compressed metadata block, and therefore, can share the start block.
|
||||
* Directories are therefore organised in a two level list, a directory
|
||||
* header containing the shared start block value, and a sequence of directory
|
||||
* entries, each of which share the shared start block. A new directory header
|
||||
* is written once/if the inode start block changes. The directory
|
||||
* header/directory entry list is repeated as many times as necessary.
|
||||
*
|
||||
* Directories are sorted, and can contain a directory index to speed up
|
||||
* file lookup. Directory indexes store one entry per metablock, each entry
|
||||
* storing the index/filename mapping to the first directory header
|
||||
* in each metadata block. Directories are sorted in alphabetical order,
|
||||
* and at lookup the index is scanned linearly looking for the first filename
|
||||
* alphabetically larger than the filename being looked up. At this point the
|
||||
* location of the metadata block the filename is in has been found.
|
||||
* The general idea of the index is ensure only one metadata block needs to be
|
||||
* decompressed to do a lookup irrespective of the length of the directory.
|
||||
* This scheme has the advantage that it doesn't require extra memory overhead
|
||||
* and doesn't require much extra storage on disk.
|
||||
*/
|
||||
|
||||
#include <linux/fs.h>
|
||||
#include <linux/vfs.h>
|
||||
#include <linux/slab.h>
|
||||
#include <linux/string.h>
|
||||
#include <linux/dcache.h>
|
||||
#include <linux/zlib.h>
|
||||
|
||||
#include "squashfs_fs.h"
|
||||
#include "squashfs_fs_sb.h"
|
||||
#include "squashfs_fs_i.h"
|
||||
#include "squashfs.h"
|
||||
|
||||
/*
|
||||
* Lookup name in the directory index, returning the location of the metadata
|
||||
* block containing it, and the directory index this represents.
|
||||
*
|
||||
* If we get an error reading the index then return the part of the index
|
||||
* (if any) we have managed to read - the index isn't essential, just
|
||||
* quicker.
|
||||
*/
|
||||
static int get_dir_index_using_name(struct super_block *sb,
|
||||
u64 *next_block, int *next_offset, u64 index_start,
|
||||
int index_offset, int i_count, const char *name,
|
||||
int len)
|
||||
{
|
||||
struct squashfs_sb_info *msblk = sb->s_fs_info;
|
||||
int i, size, length = 0, err;
|
||||
struct squashfs_dir_index *index;
|
||||
char *str;
|
||||
|
||||
TRACE("Entered get_dir_index_using_name, i_count %d\n", i_count);
|
||||
|
||||
index = kmalloc(sizeof(*index) + SQUASHFS_NAME_LEN * 2 + 2, GFP_KERNEL);
|
||||
if (index == NULL) {
|
||||
ERROR("Failed to allocate squashfs_dir_index\n");
|
||||
goto out;
|
||||
}
|
||||
|
||||
str = &index->name[SQUASHFS_NAME_LEN + 1];
|
||||
strncpy(str, name, len);
|
||||
str[len] = '\0';
|
||||
|
||||
for (i = 0; i < i_count; i++) {
|
||||
err = squashfs_read_metadata(sb, index, &index_start,
|
||||
&index_offset, sizeof(*index));
|
||||
if (err < 0)
|
||||
break;
|
||||
|
||||
|
||||
size = le32_to_cpu(index->size) + 1;
|
||||
|
||||
err = squashfs_read_metadata(sb, index->name, &index_start,
|
||||
&index_offset, size);
|
||||
if (err < 0)
|
||||
break;
|
||||
|
||||
index->name[size] = '\0';
|
||||
|
||||
if (strcmp(index->name, str) > 0)
|
||||
break;
|
||||
|
||||
length = le32_to_cpu(index->index);
|
||||
*next_block = le32_to_cpu(index->start_block) +
|
||||
msblk->directory_table;
|
||||
}
|
||||
|
||||
*next_offset = (length + *next_offset) % SQUASHFS_METADATA_SIZE;
|
||||
kfree(index);
|
||||
|
||||
out:
|
||||
/*
|
||||
* Return index (f_pos) of the looked up metadata block. Translate
|
||||
* from internal f_pos to external f_pos which is offset by 3 because
|
||||
* we invent "." and ".." entries which are not actually stored in the
|
||||
* directory.
|
||||
*/
|
||||
return length + 3;
|
||||
}
|
||||
|
||||
|
||||
static struct dentry *squashfs_lookup(struct inode *dir, struct dentry *dentry,
|
||||
struct nameidata *nd)
|
||||
{
|
||||
const unsigned char *name = dentry->d_name.name;
|
||||
int len = dentry->d_name.len;
|
||||
struct inode *inode = NULL;
|
||||
struct squashfs_sb_info *msblk = dir->i_sb->s_fs_info;
|
||||
struct squashfs_dir_header dirh;
|
||||
struct squashfs_dir_entry *dire;
|
||||
u64 block = squashfs_i(dir)->start + msblk->directory_table;
|
||||
int offset = squashfs_i(dir)->offset;
|
||||
int err, length = 0, dir_count, size;
|
||||
|
||||
TRACE("Entered squashfs_lookup [%llx:%x]\n", block, offset);
|
||||
|
||||
dire = kmalloc(sizeof(*dire) + SQUASHFS_NAME_LEN + 1, GFP_KERNEL);
|
||||
if (dire == NULL) {
|
||||
ERROR("Failed to allocate squashfs_dir_entry\n");
|
||||
return ERR_PTR(-ENOMEM);
|
||||
}
|
||||
|
||||
if (len > SQUASHFS_NAME_LEN) {
|
||||
err = -ENAMETOOLONG;
|
||||
goto failed;
|
||||
}
|
||||
|
||||
length = get_dir_index_using_name(dir->i_sb, &block, &offset,
|
||||
squashfs_i(dir)->dir_idx_start,
|
||||
squashfs_i(dir)->dir_idx_offset,
|
||||
squashfs_i(dir)->dir_idx_cnt, name, len);
|
||||
|
||||
while (length < i_size_read(dir)) {
|
||||
/*
|
||||
* Read directory header.
|
||||
*/
|
||||
err = squashfs_read_metadata(dir->i_sb, &dirh, &block,
|
||||
&offset, sizeof(dirh));
|
||||
if (err < 0)
|
||||
goto read_failure;
|
||||
|
||||
length += sizeof(dirh);
|
||||
|
||||
dir_count = le32_to_cpu(dirh.count) + 1;
|
||||
while (dir_count--) {
|
||||
/*
|
||||
* Read directory entry.
|
||||
*/
|
||||
err = squashfs_read_metadata(dir->i_sb, dire, &block,
|
||||
&offset, sizeof(*dire));
|
||||
if (err < 0)
|
||||
goto read_failure;
|
||||
|
||||
size = le16_to_cpu(dire->size) + 1;
|
||||
|
||||
err = squashfs_read_metadata(dir->i_sb, dire->name,
|
||||
&block, &offset, size);
|
||||
if (err < 0)
|
||||
goto read_failure;
|
||||
|
||||
length += sizeof(*dire) + size;
|
||||
|
||||
if (name[0] < dire->name[0])
|
||||
goto exit_lookup;
|
||||
|
||||
if (len == size && !strncmp(name, dire->name, len)) {
|
||||
unsigned int blk, off, ino_num;
|
||||
long long ino;
|
||||
blk = le32_to_cpu(dirh.start_block);
|
||||
off = le16_to_cpu(dire->offset);
|
||||
ino_num = le32_to_cpu(dirh.inode_number) +
|
||||
(short) le16_to_cpu(dire->inode_number);
|
||||
ino = SQUASHFS_MKINODE(blk, off);
|
||||
|
||||
TRACE("calling squashfs_iget for directory "
|
||||
"entry %s, inode %x:%x, %d\n", name,
|
||||
blk, off, ino_num);
|
||||
|
||||
inode = squashfs_iget(dir->i_sb, ino, ino_num);
|
||||
if (IS_ERR(inode)) {
|
||||
err = PTR_ERR(inode);
|
||||
goto failed;
|
||||
}
|
||||
|
||||
goto exit_lookup;
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
exit_lookup:
|
||||
kfree(dire);
|
||||
if (inode)
|
||||
return d_splice_alias(inode, dentry);
|
||||
d_add(dentry, inode);
|
||||
return ERR_PTR(0);
|
||||
|
||||
read_failure:
|
||||
ERROR("Unable to read directory block [%llx:%x]\n",
|
||||
squashfs_i(dir)->start + msblk->directory_table,
|
||||
squashfs_i(dir)->offset);
|
||||
failed:
|
||||
kfree(dire);
|
||||
return ERR_PTR(err);
|
||||
}
|
||||
|
||||
|
||||
const struct inode_operations squashfs_dir_inode_ops = {
|
||||
.lookup = squashfs_lookup
|
||||
};
|
||||
|
|
@ -0,0 +1,90 @@
|
|||
/*
|
||||
* Squashfs - a compressed read only filesystem for Linux
|
||||
*
|
||||
* Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008
|
||||
* Phillip Lougher <phillip@lougher.demon.co.uk>
|
||||
*
|
||||
* This program is free software; you can redistribute it and/or
|
||||
* modify it under the terms of the GNU General Public License
|
||||
* as published by the Free Software Foundation; either version 2,
|
||||
* or (at your option) any later version.
|
||||
*
|
||||
* This program is distributed in the hope that it will be useful,
|
||||
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||||
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
||||
* GNU General Public License for more details.
|
||||
*
|
||||
* You should have received a copy of the GNU General Public License
|
||||
* along with this program; if not, write to the Free Software
|
||||
* Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
|
||||
*
|
||||
* squashfs.h
|
||||
*/
|
||||
|
||||
#define TRACE(s, args...) pr_debug("SQUASHFS: "s, ## args)
|
||||
|
||||
#define ERROR(s, args...) pr_err("SQUASHFS error: "s, ## args)
|
||||
|
||||
#define WARNING(s, args...) pr_warning("SQUASHFS: "s, ## args)
|
||||
|
||||
static inline struct squashfs_inode_info *squashfs_i(struct inode *inode)
|
||||
{
|
||||
return list_entry(inode, struct squashfs_inode_info, vfs_inode);
|
||||
}
|
||||
|
||||
/* block.c */
|
||||
extern int squashfs_read_data(struct super_block *, void **, u64, int, u64 *,
|
||||
int);
|
||||
|
||||
/* cache.c */
|
||||
extern struct squashfs_cache *squashfs_cache_init(char *, int, int);
|
||||
extern void squashfs_cache_delete(struct squashfs_cache *);
|
||||
extern struct squashfs_cache_entry *squashfs_cache_get(struct super_block *,
|
||||
struct squashfs_cache *, u64, int);
|
||||
extern void squashfs_cache_put(struct squashfs_cache_entry *);
|
||||
extern int squashfs_copy_data(void *, struct squashfs_cache_entry *, int, int);
|
||||
extern int squashfs_read_metadata(struct super_block *, void *, u64 *,
|
||||
int *, int);
|
||||
extern struct squashfs_cache_entry *squashfs_get_fragment(struct super_block *,
|
||||
u64, int);
|
||||
extern struct squashfs_cache_entry *squashfs_get_datablock(struct super_block *,
|
||||
u64, int);
|
||||
extern int squashfs_read_table(struct super_block *, void *, u64, int);
|
||||
|
||||
/* export.c */
|
||||
extern __le64 *squashfs_read_inode_lookup_table(struct super_block *, u64,
|
||||
unsigned int);
|
||||
|
||||
/* fragment.c */
|
||||
extern int squashfs_frag_lookup(struct super_block *, unsigned int, u64 *);
|
||||
extern __le64 *squashfs_read_fragment_index_table(struct super_block *,
|
||||
u64, unsigned int);
|
||||
|
||||
/* id.c */
|
||||
extern int squashfs_get_id(struct super_block *, unsigned int, unsigned int *);
|
||||
extern __le64 *squashfs_read_id_index_table(struct super_block *, u64,
|
||||
unsigned short);
|
||||
|
||||
/* inode.c */
|
||||
extern struct inode *squashfs_iget(struct super_block *, long long,
|
||||
unsigned int);
|
||||
extern int squashfs_read_inode(struct inode *, long long);
|
||||
|
||||
/*
|
||||
* Inodes and files operations
|
||||
*/
|
||||
|
||||
/* dir.c */
|
||||
extern const struct file_operations squashfs_dir_ops;
|
||||
|
||||
/* export.c */
|
||||
extern const struct export_operations squashfs_export_ops;
|
||||
|
||||
/* file.c */
|
||||
extern const struct address_space_operations squashfs_aops;
|
||||
|
||||
/* namei.c */
|
||||
extern const struct inode_operations squashfs_dir_inode_ops;
|
||||
|
||||
/* symlink.c */
|
||||
extern const struct address_space_operations squashfs_symlink_aops;
|
||||
|
|
@ -0,0 +1,381 @@
|
|||
#ifndef SQUASHFS_FS
|
||||
#define SQUASHFS_FS
|
||||
/*
|
||||
* Squashfs
|
||||
*
|
||||
* Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008
|
||||
* Phillip Lougher <phillip@lougher.demon.co.uk>
|
||||
*
|
||||
* This program is free software; you can redistribute it and/or
|
||||
* modify it under the terms of the GNU General Public License
|
||||
* as published by the Free Software Foundation; either version 2,
|
||||
* or (at your option) any later version.
|
||||
*
|
||||
* This program is distributed in the hope that it will be useful,
|
||||
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||||
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
||||
* GNU General Public License for more details.
|
||||
*
|
||||
* You should have received a copy of the GNU General Public License
|
||||
* along with this program; if not, write to the Free Software
|
||||
* Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
|
||||
*
|
||||
* squashfs_fs.h
|
||||
*/
|
||||
|
||||
#define SQUASHFS_CACHED_FRAGMENTS CONFIG_SQUASHFS_FRAGMENT_CACHE_SIZE
|
||||
#define SQUASHFS_MAJOR 4
|
||||
#define SQUASHFS_MINOR 0
|
||||
#define SQUASHFS_MAGIC 0x73717368
|
||||
#define SQUASHFS_START 0
|
||||
|
||||
/* size of metadata (inode and directory) blocks */
|
||||
#define SQUASHFS_METADATA_SIZE 8192
|
||||
#define SQUASHFS_METADATA_LOG 13
|
||||
|
||||
/* default size of data blocks */
|
||||
#define SQUASHFS_FILE_SIZE 131072
|
||||
#define SQUASHFS_FILE_LOG 17
|
||||
|
||||
#define SQUASHFS_FILE_MAX_SIZE 1048576
|
||||
#define SQUASHFS_FILE_MAX_LOG 20
|
||||
|
||||
/* Max number of uids and gids */
|
||||
#define SQUASHFS_IDS 65536
|
||||
|
||||
/* Max length of filename (not 255) */
|
||||
#define SQUASHFS_NAME_LEN 256
|
||||
|
||||
#define SQUASHFS_INVALID_FRAG (0xffffffffU)
|
||||
#define SQUASHFS_INVALID_BLK (-1LL)
|
||||
|
||||
/* Filesystem flags */
|
||||
#define SQUASHFS_NOI 0
|
||||
#define SQUASHFS_NOD 1
|
||||
#define SQUASHFS_NOF 3
|
||||
#define SQUASHFS_NO_FRAG 4
|
||||
#define SQUASHFS_ALWAYS_FRAG 5
|
||||
#define SQUASHFS_DUPLICATE 6
|
||||
#define SQUASHFS_EXPORT 7
|
||||
|
||||
#define SQUASHFS_BIT(flag, bit) ((flag >> bit) & 1)
|
||||
|
||||
#define SQUASHFS_UNCOMPRESSED_INODES(flags) SQUASHFS_BIT(flags, \
|
||||
SQUASHFS_NOI)
|
||||
|
||||
#define SQUASHFS_UNCOMPRESSED_DATA(flags) SQUASHFS_BIT(flags, \
|
||||
SQUASHFS_NOD)
|
||||
|
||||
#define SQUASHFS_UNCOMPRESSED_FRAGMENTS(flags) SQUASHFS_BIT(flags, \
|
||||
SQUASHFS_NOF)
|
||||
|
||||
#define SQUASHFS_NO_FRAGMENTS(flags) SQUASHFS_BIT(flags, \
|
||||
SQUASHFS_NO_FRAG)
|
||||
|
||||
#define SQUASHFS_ALWAYS_FRAGMENTS(flags) SQUASHFS_BIT(flags, \
|
||||
SQUASHFS_ALWAYS_FRAG)
|
||||
|
||||
#define SQUASHFS_DUPLICATES(flags) SQUASHFS_BIT(flags, \
|
||||
SQUASHFS_DUPLICATE)
|
||||
|
||||
#define SQUASHFS_EXPORTABLE(flags) SQUASHFS_BIT(flags, \
|
||||
SQUASHFS_EXPORT)
|
||||
|
||||
/* Max number of types and file types */
|
||||
#define SQUASHFS_DIR_TYPE 1
|
||||
#define SQUASHFS_REG_TYPE 2
|
||||
#define SQUASHFS_SYMLINK_TYPE 3
|
||||
#define SQUASHFS_BLKDEV_TYPE 4
|
||||
#define SQUASHFS_CHRDEV_TYPE 5
|
||||
#define SQUASHFS_FIFO_TYPE 6
|
||||
#define SQUASHFS_SOCKET_TYPE 7
|
||||
#define SQUASHFS_LDIR_TYPE 8
|
||||
#define SQUASHFS_LREG_TYPE 9
|
||||
#define SQUASHFS_LSYMLINK_TYPE 10
|
||||
#define SQUASHFS_LBLKDEV_TYPE 11
|
||||
#define SQUASHFS_LCHRDEV_TYPE 12
|
||||
#define SQUASHFS_LFIFO_TYPE 13
|
||||
#define SQUASHFS_LSOCKET_TYPE 14
|
||||
|
||||
/* Flag whether block is compressed or uncompressed, bit is set if block is
|
||||
* uncompressed */
|
||||
#define SQUASHFS_COMPRESSED_BIT (1 << 15)
|
||||
|
||||
#define SQUASHFS_COMPRESSED_SIZE(B) (((B) & ~SQUASHFS_COMPRESSED_BIT) ? \
|
||||
(B) & ~SQUASHFS_COMPRESSED_BIT : SQUASHFS_COMPRESSED_BIT)
|
||||
|
||||
#define SQUASHFS_COMPRESSED(B) (!((B) & SQUASHFS_COMPRESSED_BIT))
|
||||
|
||||
#define SQUASHFS_COMPRESSED_BIT_BLOCK (1 << 24)
|
||||
|
||||
#define SQUASHFS_COMPRESSED_SIZE_BLOCK(B) ((B) & \
|
||||
~SQUASHFS_COMPRESSED_BIT_BLOCK)
|
||||
|
||||
#define SQUASHFS_COMPRESSED_BLOCK(B) (!((B) & SQUASHFS_COMPRESSED_BIT_BLOCK))
|
||||
|
||||
/*
|
||||
* Inode number ops. Inodes consist of a compressed block number, and an
|
||||
* uncompressed offset within that block
|
||||
*/
|
||||
#define SQUASHFS_INODE_BLK(A) ((unsigned int) ((A) >> 16))
|
||||
|
||||
#define SQUASHFS_INODE_OFFSET(A) ((unsigned int) ((A) & 0xffff))
|
||||
|
||||
#define SQUASHFS_MKINODE(A, B) ((long long)(((long long) (A)\
|
||||
<< 16) + (B)))
|
||||
|
||||
/* Translate between VFS mode and squashfs mode */
|
||||
#define SQUASHFS_MODE(A) ((A) & 0xfff)
|
||||
|
||||
/* fragment and fragment table defines */
|
||||
#define SQUASHFS_FRAGMENT_BYTES(A) \
|
||||
((A) * sizeof(struct squashfs_fragment_entry))
|
||||
|
||||
#define SQUASHFS_FRAGMENT_INDEX(A) (SQUASHFS_FRAGMENT_BYTES(A) / \
|
||||
SQUASHFS_METADATA_SIZE)
|
||||
|
||||
#define SQUASHFS_FRAGMENT_INDEX_OFFSET(A) (SQUASHFS_FRAGMENT_BYTES(A) % \
|
||||
SQUASHFS_METADATA_SIZE)
|
||||
|
||||
#define SQUASHFS_FRAGMENT_INDEXES(A) ((SQUASHFS_FRAGMENT_BYTES(A) + \
|
||||
SQUASHFS_METADATA_SIZE - 1) / \
|
||||
SQUASHFS_METADATA_SIZE)
|
||||
|
||||
#define SQUASHFS_FRAGMENT_INDEX_BYTES(A) (SQUASHFS_FRAGMENT_INDEXES(A) *\
|
||||
sizeof(u64))
|
||||
|
||||
/* inode lookup table defines */
|
||||
#define SQUASHFS_LOOKUP_BYTES(A) ((A) * sizeof(u64))
|
||||
|
||||
#define SQUASHFS_LOOKUP_BLOCK(A) (SQUASHFS_LOOKUP_BYTES(A) / \
|
||||
SQUASHFS_METADATA_SIZE)
|
||||
|
||||
#define SQUASHFS_LOOKUP_BLOCK_OFFSET(A) (SQUASHFS_LOOKUP_BYTES(A) % \
|
||||
SQUASHFS_METADATA_SIZE)
|
||||
|
||||
#define SQUASHFS_LOOKUP_BLOCKS(A) ((SQUASHFS_LOOKUP_BYTES(A) + \
|
||||
SQUASHFS_METADATA_SIZE - 1) / \
|
||||
SQUASHFS_METADATA_SIZE)
|
||||
|
||||
#define SQUASHFS_LOOKUP_BLOCK_BYTES(A) (SQUASHFS_LOOKUP_BLOCKS(A) *\
|
||||
sizeof(u64))
|
||||
|
||||
/* uid/gid lookup table defines */
|
||||
#define SQUASHFS_ID_BYTES(A) ((A) * sizeof(unsigned int))
|
||||
|
||||
#define SQUASHFS_ID_BLOCK(A) (SQUASHFS_ID_BYTES(A) / \
|
||||
SQUASHFS_METADATA_SIZE)
|
||||
|
||||
#define SQUASHFS_ID_BLOCK_OFFSET(A) (SQUASHFS_ID_BYTES(A) % \
|
||||
SQUASHFS_METADATA_SIZE)
|
||||
|
||||
#define SQUASHFS_ID_BLOCKS(A) ((SQUASHFS_ID_BYTES(A) + \
|
||||
SQUASHFS_METADATA_SIZE - 1) / \
|
||||
SQUASHFS_METADATA_SIZE)
|
||||
|
||||
#define SQUASHFS_ID_BLOCK_BYTES(A) (SQUASHFS_ID_BLOCKS(A) *\
|
||||
sizeof(u64))
|
||||
|
||||
/* cached data constants for filesystem */
|
||||
#define SQUASHFS_CACHED_BLKS 8
|
||||
|
||||
#define SQUASHFS_MAX_FILE_SIZE_LOG 64
|
||||
|
||||
#define SQUASHFS_MAX_FILE_SIZE (1LL << \
|
||||
(SQUASHFS_MAX_FILE_SIZE_LOG - 2))
|
||||
|
||||
#define SQUASHFS_MARKER_BYTE 0xff
|
||||
|
||||
/* meta index cache */
|
||||
#define SQUASHFS_META_INDEXES (SQUASHFS_METADATA_SIZE / sizeof(unsigned int))
|
||||
#define SQUASHFS_META_ENTRIES 127
|
||||
#define SQUASHFS_META_SLOTS 8
|
||||
|
||||
struct meta_entry {
|
||||
u64 data_block;
|
||||
unsigned int index_block;
|
||||
unsigned short offset;
|
||||
unsigned short pad;
|
||||
};
|
||||
|
||||
struct meta_index {
|
||||
unsigned int inode_number;
|
||||
unsigned int offset;
|
||||
unsigned short entries;
|
||||
unsigned short skip;
|
||||
unsigned short locked;
|
||||
unsigned short pad;
|
||||
struct meta_entry meta_entry[SQUASHFS_META_ENTRIES];
|
||||
};
|
||||
|
||||
|
||||
/*
|
||||
* definitions for structures on disk
|
||||
*/
|
||||
#define ZLIB_COMPRESSION 1
|
||||
|
||||
struct squashfs_super_block {
|
||||
__le32 s_magic;
|
||||
__le32 inodes;
|
||||
__le32 mkfs_time;
|
||||
__le32 block_size;
|
||||
__le32 fragments;
|
||||
__le16 compression;
|
||||
__le16 block_log;
|
||||
__le16 flags;
|
||||
__le16 no_ids;
|
||||
__le16 s_major;
|
||||
__le16 s_minor;
|
||||
__le64 root_inode;
|
||||
__le64 bytes_used;
|
||||
__le64 id_table_start;
|
||||
__le64 xattr_table_start;
|
||||
__le64 inode_table_start;
|
||||
__le64 directory_table_start;
|
||||
__le64 fragment_table_start;
|
||||
__le64 lookup_table_start;
|
||||
};
|
||||
|
||||
struct squashfs_dir_index {
|
||||
__le32 index;
|
||||
__le32 start_block;
|
||||
__le32 size;
|
||||
unsigned char name[0];
|
||||
};
|
||||
|
||||
struct squashfs_base_inode {
|
||||
__le16 inode_type;
|
||||
__le16 mode;
|
||||
__le16 uid;
|
||||
__le16 guid;
|
||||
__le32 mtime;
|
||||
__le32 inode_number;
|
||||
};
|
||||
|
||||
struct squashfs_ipc_inode {
|
||||
__le16 inode_type;
|
||||
__le16 mode;
|
||||
__le16 uid;
|
||||
__le16 guid;
|
||||
__le32 mtime;
|
||||
__le32 inode_number;
|
||||
__le32 nlink;
|
||||
};
|
||||
|
||||
struct squashfs_dev_inode {
|
||||
__le16 inode_type;
|
||||
__le16 mode;
|
||||
__le16 uid;
|
||||
__le16 guid;
|
||||
__le32 mtime;
|
||||
__le32 inode_number;
|
||||
__le32 nlink;
|
||||
__le32 rdev;
|
||||
};
|
||||
|
||||
struct squashfs_symlink_inode {
|
||||
__le16 inode_type;
|
||||
__le16 mode;
|
||||
__le16 uid;
|
||||
__le16 guid;
|
||||
__le32 mtime;
|
||||
__le32 inode_number;
|
||||
__le32 nlink;
|
||||
__le32 symlink_size;
|
||||
char symlink[0];
|
||||
};
|
||||
|
||||
struct squashfs_reg_inode {
|
||||
__le16 inode_type;
|
||||
__le16 mode;
|
||||
__le16 uid;
|
||||
__le16 guid;
|
||||
__le32 mtime;
|
||||
__le32 inode_number;
|
||||
__le32 start_block;
|
||||
__le32 fragment;
|
||||
__le32 offset;
|
||||
__le32 file_size;
|
||||
__le16 block_list[0];
|
||||
};
|
||||
|
||||
struct squashfs_lreg_inode {
|
||||
__le16 inode_type;
|
||||
__le16 mode;
|
||||
__le16 uid;
|
||||
__le16 guid;
|
||||
__le32 mtime;
|
||||
__le32 inode_number;
|
||||
__le64 start_block;
|
||||
__le64 file_size;
|
||||
__le64 sparse;
|
||||
__le32 nlink;
|
||||
__le32 fragment;
|
||||
__le32 offset;
|
||||
__le32 xattr;
|
||||
__le16 block_list[0];
|
||||
};
|
||||
|
||||
struct squashfs_dir_inode {
|
||||
__le16 inode_type;
|
||||
__le16 mode;
|
||||
__le16 uid;
|
||||
__le16 guid;
|
||||
__le32 mtime;
|
||||
__le32 inode_number;
|
||||
__le32 start_block;
|
||||
__le32 nlink;
|
||||
__le16 file_size;
|
||||
__le16 offset;
|
||||
__le32 parent_inode;
|
||||
};
|
||||
|
||||
struct squashfs_ldir_inode {
|
||||
__le16 inode_type;
|
||||
__le16 mode;
|
||||
__le16 uid;
|
||||
__le16 guid;
|
||||
__le32 mtime;
|
||||
__le32 inode_number;
|
||||
__le32 nlink;
|
||||
__le32 file_size;
|
||||
__le32 start_block;
|
||||
__le32 parent_inode;
|
||||
__le16 i_count;
|
||||
__le16 offset;
|
||||
__le32 xattr;
|
||||
struct squashfs_dir_index index[0];
|
||||
};
|
||||
|
||||
union squashfs_inode {
|
||||
struct squashfs_base_inode base;
|
||||
struct squashfs_dev_inode dev;
|
||||
struct squashfs_symlink_inode symlink;
|
||||
struct squashfs_reg_inode reg;
|
||||
struct squashfs_lreg_inode lreg;
|
||||
struct squashfs_dir_inode dir;
|
||||
struct squashfs_ldir_inode ldir;
|
||||
struct squashfs_ipc_inode ipc;
|
||||
};
|
||||
|
||||
struct squashfs_dir_entry {
|
||||
__le16 offset;
|
||||
__le16 inode_number;
|
||||
__le16 type;
|
||||
__le16 size;
|
||||
char name[0];
|
||||
};
|
||||
|
||||
struct squashfs_dir_header {
|
||||
__le32 count;
|
||||
__le32 start_block;
|
||||
__le32 inode_number;
|
||||
};
|
||||
|
||||
struct squashfs_fragment_entry {
|
||||
__le64 start_block;
|
||||
__le32 size;
|
||||
unsigned int unused;
|
||||
};
|
||||
|
||||
#endif
|
||||
|
|
@ -0,0 +1,45 @@
|
|||
#ifndef SQUASHFS_FS_I
|
||||
#define SQUASHFS_FS_I
|
||||
/*
|
||||
* Squashfs
|
||||
*
|
||||
* Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008
|
||||
* Phillip Lougher <phillip@lougher.demon.co.uk>
|
||||
*
|
||||
* This program is free software; you can redistribute it and/or
|
||||
* modify it under the terms of the GNU General Public License
|
||||
* as published by the Free Software Foundation; either version 2,
|
||||
* or (at your option) any later version.
|
||||
*
|
||||
* This program is distributed in the hope that it will be useful,
|
||||
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||||
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
||||
* GNU General Public License for more details.
|
||||
*
|
||||
* You should have received a copy of the GNU General Public License
|
||||
* along with this program; if not, write to the Free Software
|
||||
* Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
|
||||
*
|
||||
* squashfs_fs_i.h
|
||||
*/
|
||||
|
||||
struct squashfs_inode_info {
|
||||
u64 start;
|
||||
int offset;
|
||||
union {
|
||||
struct {
|
||||
u64 fragment_block;
|
||||
int fragment_size;
|
||||
int fragment_offset;
|
||||
u64 block_list_start;
|
||||
};
|
||||
struct {
|
||||
u64 dir_idx_start;
|
||||
int dir_idx_offset;
|
||||
int dir_idx_cnt;
|
||||
int parent;
|
||||
};
|
||||
};
|
||||
struct inode vfs_inode;
|
||||
};
|
||||
#endif
|
||||
|
|
@ -0,0 +1,76 @@
|
|||
#ifndef SQUASHFS_FS_SB
|
||||
#define SQUASHFS_FS_SB
|
||||
/*
|
||||
* Squashfs
|
||||
*
|
||||
* Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008
|
||||
* Phillip Lougher <phillip@lougher.demon.co.uk>
|
||||
*
|
||||
* This program is free software; you can redistribute it and/or
|
||||
* modify it under the terms of the GNU General Public License
|
||||
* as published by the Free Software Foundation; either version 2,
|
||||
* or (at your option) any later version.
|
||||
*
|
||||
* This program is distributed in the hope that it will be useful,
|
||||
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||||
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
||||
* GNU General Public License for more details.
|
||||
*
|
||||
* You should have received a copy of the GNU General Public License
|
||||
* along with this program; if not, write to the Free Software
|
||||
* Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
|
||||
*
|
||||
* squashfs_fs_sb.h
|
||||
*/
|
||||
|
||||
#include "squashfs_fs.h"
|
||||
|
||||
struct squashfs_cache {
|
||||
char *name;
|
||||
int entries;
|
||||
int next_blk;
|
||||
int num_waiters;
|
||||
int unused;
|
||||
int block_size;
|
||||
int pages;
|
||||
spinlock_t lock;
|
||||
wait_queue_head_t wait_queue;
|
||||
struct squashfs_cache_entry *entry;
|
||||
};
|
||||
|
||||
struct squashfs_cache_entry {
|
||||
u64 block;
|
||||
int length;
|
||||
int refcount;
|
||||
u64 next_index;
|
||||
int pending;
|
||||
int error;
|
||||
int num_waiters;
|
||||
wait_queue_head_t wait_queue;
|
||||
struct squashfs_cache *cache;
|
||||
void **data;
|
||||
};
|
||||
|
||||
struct squashfs_sb_info {
|
||||
int devblksize;
|
||||
int devblksize_log2;
|
||||
struct squashfs_cache *block_cache;
|
||||
struct squashfs_cache *fragment_cache;
|
||||
struct squashfs_cache *read_page;
|
||||
int next_meta_index;
|
||||
__le64 *id_table;
|
||||
__le64 *fragment_index;
|
||||
unsigned int *fragment_index_2;
|
||||
struct mutex read_data_mutex;
|
||||
struct mutex meta_index_mutex;
|
||||
struct meta_index *meta_index;
|
||||
z_stream stream;
|
||||
__le64 *inode_lookup_table;
|
||||
u64 inode_table;
|
||||
u64 directory_table;
|
||||
unsigned int block_size;
|
||||
unsigned short block_log;
|
||||
long long bytes_used;
|
||||
unsigned int inodes;
|
||||
};
|
||||
#endif
|
||||
|
|
@ -0,0 +1,440 @@
|
|||
/*
|
||||
* Squashfs - a compressed read only filesystem for Linux
|
||||
*
|
||||
* Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008
|
||||
* Phillip Lougher <phillip@lougher.demon.co.uk>
|
||||
*
|
||||
* This program is free software; you can redistribute it and/or
|
||||
* modify it under the terms of the GNU General Public License
|
||||
* as published by the Free Software Foundation; either version 2,
|
||||
* or (at your option) any later version.
|
||||
*
|
||||
* This program is distributed in the hope that it will be useful,
|
||||
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||||
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
||||
* GNU General Public License for more details.
|
||||
*
|
||||
* You should have received a copy of the GNU General Public License
|
||||
* along with this program; if not, write to the Free Software
|
||||
* Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
|
||||
*
|
||||
* super.c
|
||||
*/
|
||||
|
||||
/*
|
||||
* This file implements code to read the superblock, read and initialise
|
||||
* in-memory structures at mount time, and all the VFS glue code to register
|
||||
* the filesystem.
|
||||
*/
|
||||
|
||||
#include <linux/fs.h>
|
||||
#include <linux/vfs.h>
|
||||
#include <linux/slab.h>
|
||||
#include <linux/mutex.h>
|
||||
#include <linux/pagemap.h>
|
||||
#include <linux/init.h>
|
||||
#include <linux/module.h>
|
||||
#include <linux/zlib.h>
|
||||
|
||||
#include "squashfs_fs.h"
|
||||
#include "squashfs_fs_sb.h"
|
||||
#include "squashfs_fs_i.h"
|
||||
#include "squashfs.h"
|
||||
|
||||
static struct file_system_type squashfs_fs_type;
|
||||
static struct super_operations squashfs_super_ops;
|
||||
|
||||
static int supported_squashfs_filesystem(short major, short minor, short comp)
|
||||
{
|
||||
if (major < SQUASHFS_MAJOR) {
|
||||
ERROR("Major/Minor mismatch, older Squashfs %d.%d "
|
||||
"filesystems are unsupported\n", major, minor);
|
||||
return -EINVAL;
|
||||
} else if (major > SQUASHFS_MAJOR || minor > SQUASHFS_MINOR) {
|
||||
ERROR("Major/Minor mismatch, trying to mount newer "
|
||||
"%d.%d filesystem\n", major, minor);
|
||||
ERROR("Please update your kernel\n");
|
||||
return -EINVAL;
|
||||
}
|
||||
|
||||
if (comp != ZLIB_COMPRESSION)
|
||||
return -EINVAL;
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
|
||||
static int squashfs_fill_super(struct super_block *sb, void *data, int silent)
|
||||
{
|
||||
struct squashfs_sb_info *msblk;
|
||||
struct squashfs_super_block *sblk = NULL;
|
||||
char b[BDEVNAME_SIZE];
|
||||
struct inode *root;
|
||||
long long root_inode;
|
||||
unsigned short flags;
|
||||
unsigned int fragments;
|
||||
u64 lookup_table_start;
|
||||
int err;
|
||||
|
||||
TRACE("Entered squashfs_fill_superblock\n");
|
||||
|
||||
sb->s_fs_info = kzalloc(sizeof(*msblk), GFP_KERNEL);
|
||||
if (sb->s_fs_info == NULL) {
|
||||
ERROR("Failed to allocate squashfs_sb_info\n");
|
||||
return -ENOMEM;
|
||||
}
|
||||
msblk = sb->s_fs_info;
|
||||
|
||||
msblk->stream.workspace = kmalloc(zlib_inflate_workspacesize(),
|
||||
GFP_KERNEL);
|
||||
if (msblk->stream.workspace == NULL) {
|
||||
ERROR("Failed to allocate zlib workspace\n");
|
||||
goto failure;
|
||||
}
|
||||
|
||||
sblk = kzalloc(sizeof(*sblk), GFP_KERNEL);
|
||||
if (sblk == NULL) {
|
||||
ERROR("Failed to allocate squashfs_super_block\n");
|
||||
goto failure;
|
||||
}
|
||||
|
||||
msblk->devblksize = sb_min_blocksize(sb, BLOCK_SIZE);
|
||||
msblk->devblksize_log2 = ffz(~msblk->devblksize);
|
||||
|
||||
mutex_init(&msblk->read_data_mutex);
|
||||
mutex_init(&msblk->meta_index_mutex);
|
||||
|
||||
/*
|
||||
* msblk->bytes_used is checked in squashfs_read_table to ensure reads
|
||||
* are not beyond filesystem end. But as we're using
|
||||
* squashfs_read_table here to read the superblock (including the value
|
||||
* of bytes_used) we need to set it to an initial sensible dummy value
|
||||
*/
|
||||
msblk->bytes_used = sizeof(*sblk);
|
||||
err = squashfs_read_table(sb, sblk, SQUASHFS_START, sizeof(*sblk));
|
||||
|
||||
if (err < 0) {
|
||||
ERROR("unable to read squashfs_super_block\n");
|
||||
goto failed_mount;
|
||||
}
|
||||
|
||||
/* Check it is a SQUASHFS superblock */
|
||||
sb->s_magic = le32_to_cpu(sblk->s_magic);
|
||||
if (sb->s_magic != SQUASHFS_MAGIC) {
|
||||
if (!silent)
|
||||
ERROR("Can't find a SQUASHFS superblock on %s\n",
|
||||
bdevname(sb->s_bdev, b));
|
||||
err = -EINVAL;
|
||||
goto failed_mount;
|
||||
}
|
||||
|
||||
/* Check the MAJOR & MINOR versions and compression type */
|
||||
err = supported_squashfs_filesystem(le16_to_cpu(sblk->s_major),
|
||||
le16_to_cpu(sblk->s_minor),
|
||||
le16_to_cpu(sblk->compression));
|
||||
if (err < 0)
|
||||
goto failed_mount;
|
||||
|
||||
err = -EINVAL;
|
||||
|
||||
/*
|
||||
* Check if there's xattrs in the filesystem. These are not
|
||||
* supported in this version, so warn that they will be ignored.
|
||||
*/
|
||||
if (le64_to_cpu(sblk->xattr_table_start) != SQUASHFS_INVALID_BLK)
|
||||
ERROR("Xattrs in filesystem, these will be ignored\n");
|
||||
|
||||
/* Check the filesystem does not extend beyond the end of the
|
||||
block device */
|
||||
msblk->bytes_used = le64_to_cpu(sblk->bytes_used);
|
||||
if (msblk->bytes_used < 0 || msblk->bytes_used >
|
||||
i_size_read(sb->s_bdev->bd_inode))
|
||||
goto failed_mount;
|
||||
|
||||
/* Check block size for sanity */
|
||||
msblk->block_size = le32_to_cpu(sblk->block_size);
|
||||
if (msblk->block_size > SQUASHFS_FILE_MAX_SIZE)
|
||||
goto failed_mount;
|
||||
|
||||
msblk->block_log = le16_to_cpu(sblk->block_log);
|
||||
if (msblk->block_log > SQUASHFS_FILE_MAX_LOG)
|
||||
goto failed_mount;
|
||||
|
||||
/* Check the root inode for sanity */
|
||||
root_inode = le64_to_cpu(sblk->root_inode);
|
||||
if (SQUASHFS_INODE_OFFSET(root_inode) > SQUASHFS_METADATA_SIZE)
|
||||
goto failed_mount;
|
||||
|
||||
msblk->inode_table = le64_to_cpu(sblk->inode_table_start);
|
||||
msblk->directory_table = le64_to_cpu(sblk->directory_table_start);
|
||||
msblk->inodes = le32_to_cpu(sblk->inodes);
|
||||
flags = le16_to_cpu(sblk->flags);
|
||||
|
||||
TRACE("Found valid superblock on %s\n", bdevname(sb->s_bdev, b));
|
||||
TRACE("Inodes are %scompressed\n", SQUASHFS_UNCOMPRESSED_INODES(flags)
|
||||
? "un" : "");
|
||||
TRACE("Data is %scompressed\n", SQUASHFS_UNCOMPRESSED_DATA(flags)
|
||||
? "un" : "");
|
||||
TRACE("Filesystem size %lld bytes\n", msblk->bytes_used);
|
||||
TRACE("Block size %d\n", msblk->block_size);
|
||||
TRACE("Number of inodes %d\n", msblk->inodes);
|
||||
TRACE("Number of fragments %d\n", le32_to_cpu(sblk->fragments));
|
||||
TRACE("Number of ids %d\n", le16_to_cpu(sblk->no_ids));
|
||||
TRACE("sblk->inode_table_start %llx\n", msblk->inode_table);
|
||||
TRACE("sblk->directory_table_start %llx\n", msblk->directory_table);
|
||||
TRACE("sblk->fragment_table_start %llx\n",
|
||||
(u64) le64_to_cpu(sblk->fragment_table_start));
|
||||
TRACE("sblk->id_table_start %llx\n",
|
||||
(u64) le64_to_cpu(sblk->id_table_start));
|
||||
|
||||
sb->s_maxbytes = MAX_LFS_FILESIZE;
|
||||
sb->s_flags |= MS_RDONLY;
|
||||
sb->s_op = &squashfs_super_ops;
|
||||
|
||||
err = -ENOMEM;
|
||||
|
||||
msblk->block_cache = squashfs_cache_init("metadata",
|
||||
SQUASHFS_CACHED_BLKS, SQUASHFS_METADATA_SIZE);
|
||||
if (msblk->block_cache == NULL)
|
||||
goto failed_mount;
|
||||
|
||||
/* Allocate read_page block */
|
||||
msblk->read_page = squashfs_cache_init("data", 1, msblk->block_size);
|
||||
if (msblk->read_page == NULL) {
|
||||
ERROR("Failed to allocate read_page block\n");
|
||||
goto failed_mount;
|
||||
}
|
||||
|
||||
/* Allocate and read id index table */
|
||||
msblk->id_table = squashfs_read_id_index_table(sb,
|
||||
le64_to_cpu(sblk->id_table_start), le16_to_cpu(sblk->no_ids));
|
||||
if (IS_ERR(msblk->id_table)) {
|
||||
err = PTR_ERR(msblk->id_table);
|
||||
msblk->id_table = NULL;
|
||||
goto failed_mount;
|
||||
}
|
||||
|
||||
fragments = le32_to_cpu(sblk->fragments);
|
||||
if (fragments == 0)
|
||||
goto allocate_lookup_table;
|
||||
|
||||
msblk->fragment_cache = squashfs_cache_init("fragment",
|
||||
SQUASHFS_CACHED_FRAGMENTS, msblk->block_size);
|
||||
if (msblk->fragment_cache == NULL) {
|
||||
err = -ENOMEM;
|
||||
goto failed_mount;
|
||||
}
|
||||
|
||||
/* Allocate and read fragment index table */
|
||||
msblk->fragment_index = squashfs_read_fragment_index_table(sb,
|
||||
le64_to_cpu(sblk->fragment_table_start), fragments);
|
||||
if (IS_ERR(msblk->fragment_index)) {
|
||||
err = PTR_ERR(msblk->fragment_index);
|
||||
msblk->fragment_index = NULL;
|
||||
goto failed_mount;
|
||||
}
|
||||
|
||||
allocate_lookup_table:
|
||||
lookup_table_start = le64_to_cpu(sblk->lookup_table_start);
|
||||
if (lookup_table_start == SQUASHFS_INVALID_BLK)
|
||||
goto allocate_root;
|
||||
|
||||
/* Allocate and read inode lookup table */
|
||||
msblk->inode_lookup_table = squashfs_read_inode_lookup_table(sb,
|
||||
lookup_table_start, msblk->inodes);
|
||||
if (IS_ERR(msblk->inode_lookup_table)) {
|
||||
err = PTR_ERR(msblk->inode_lookup_table);
|
||||
msblk->inode_lookup_table = NULL;
|
||||
goto failed_mount;
|
||||
}
|
||||
|
||||
sb->s_export_op = &squashfs_export_ops;
|
||||
|
||||
allocate_root:
|
||||
root = new_inode(sb);
|
||||
if (!root) {
|
||||
err = -ENOMEM;
|
||||
goto failed_mount;
|
||||
}
|
||||
|
||||
err = squashfs_read_inode(root, root_inode);
|
||||
if (err) {
|
||||
iget_failed(root);
|
||||
goto failed_mount;
|
||||
}
|
||||
insert_inode_hash(root);
|
||||
|
||||
sb->s_root = d_alloc_root(root);
|
||||
if (sb->s_root == NULL) {
|
||||
ERROR("Root inode create failed\n");
|
||||
err = -ENOMEM;
|
||||
iput(root);
|
||||
goto failed_mount;
|
||||
}
|
||||
|
||||
TRACE("Leaving squashfs_fill_super\n");
|
||||
kfree(sblk);
|
||||
return 0;
|
||||
|
||||
failed_mount:
|
||||
squashfs_cache_delete(msblk->block_cache);
|
||||
squashfs_cache_delete(msblk->fragment_cache);
|
||||
squashfs_cache_delete(msblk->read_page);
|
||||
kfree(msblk->inode_lookup_table);
|
||||
kfree(msblk->fragment_index);
|
||||
kfree(msblk->id_table);
|
||||
kfree(msblk->stream.workspace);
|
||||
kfree(sb->s_fs_info);
|
||||
sb->s_fs_info = NULL;
|
||||
kfree(sblk);
|
||||
return err;
|
||||
|
||||
failure:
|
||||
kfree(msblk->stream.workspace);
|
||||
kfree(sb->s_fs_info);
|
||||
sb->s_fs_info = NULL;
|
||||
return -ENOMEM;
|
||||
}
|
||||
|
||||
|
||||
static int squashfs_statfs(struct dentry *dentry, struct kstatfs *buf)
|
||||
{
|
||||
struct squashfs_sb_info *msblk = dentry->d_sb->s_fs_info;
|
||||
|
||||
TRACE("Entered squashfs_statfs\n");
|
||||
|
||||
buf->f_type = SQUASHFS_MAGIC;
|
||||
buf->f_bsize = msblk->block_size;
|
||||
buf->f_blocks = ((msblk->bytes_used - 1) >> msblk->block_log) + 1;
|
||||
buf->f_bfree = buf->f_bavail = 0;
|
||||
buf->f_files = msblk->inodes;
|
||||
buf->f_ffree = 0;
|
||||
buf->f_namelen = SQUASHFS_NAME_LEN;
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
|
||||
static int squashfs_remount(struct super_block *sb, int *flags, char *data)
|
||||
{
|
||||
*flags |= MS_RDONLY;
|
||||
return 0;
|
||||
}
|
||||
|
||||
|
||||
static void squashfs_put_super(struct super_block *sb)
|
||||
{
|
||||
if (sb->s_fs_info) {
|
||||
struct squashfs_sb_info *sbi = sb->s_fs_info;
|
||||
squashfs_cache_delete(sbi->block_cache);
|
||||
squashfs_cache_delete(sbi->fragment_cache);
|
||||
squashfs_cache_delete(sbi->read_page);
|
||||
kfree(sbi->id_table);
|
||||
kfree(sbi->fragment_index);
|
||||
kfree(sbi->meta_index);
|
||||
kfree(sbi->stream.workspace);
|
||||
kfree(sb->s_fs_info);
|
||||
sb->s_fs_info = NULL;
|
||||
}
|
||||
}
|
||||
|
||||
|
||||
static int squashfs_get_sb(struct file_system_type *fs_type, int flags,
|
||||
const char *dev_name, void *data,
|
||||
struct vfsmount *mnt)
|
||||
{
|
||||
return get_sb_bdev(fs_type, flags, dev_name, data, squashfs_fill_super,
|
||||
mnt);
|
||||
}
|
||||
|
||||
|
||||
static struct kmem_cache *squashfs_inode_cachep;
|
||||
|
||||
|
||||
static void init_once(void *foo)
|
||||
{
|
||||
struct squashfs_inode_info *ei = foo;
|
||||
|
||||
inode_init_once(&ei->vfs_inode);
|
||||
}
|
||||
|
||||
|
||||
static int __init init_inodecache(void)
|
||||
{
|
||||
squashfs_inode_cachep = kmem_cache_create("squashfs_inode_cache",
|
||||
sizeof(struct squashfs_inode_info), 0,
|
||||
SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT, init_once);
|
||||
|
||||
return squashfs_inode_cachep ? 0 : -ENOMEM;
|
||||
}
|
||||
|
||||
|
||||
static void destroy_inodecache(void)
|
||||
{
|
||||
kmem_cache_destroy(squashfs_inode_cachep);
|
||||
}
|
||||
|
||||
|
||||
static int __init init_squashfs_fs(void)
|
||||
{
|
||||
int err = init_inodecache();
|
||||
|
||||
if (err)
|
||||
return err;
|
||||
|
||||
err = register_filesystem(&squashfs_fs_type);
|
||||
if (err) {
|
||||
destroy_inodecache();
|
||||
return err;
|
||||
}
|
||||
|
||||
printk(KERN_INFO "squashfs: version 4.0 (2009/01/03) "
|
||||
"Phillip Lougher\n");
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
|
||||
static void __exit exit_squashfs_fs(void)
|
||||
{
|
||||
unregister_filesystem(&squashfs_fs_type);
|
||||
destroy_inodecache();
|
||||
}
|
||||
|
||||
|
||||
static struct inode *squashfs_alloc_inode(struct super_block *sb)
|
||||
{
|
||||
struct squashfs_inode_info *ei =
|
||||
kmem_cache_alloc(squashfs_inode_cachep, GFP_KERNEL);
|
||||
|
||||
return ei ? &ei->vfs_inode : NULL;
|
||||
}
|
||||
|
||||
|
||||
static void squashfs_destroy_inode(struct inode *inode)
|
||||
{
|
||||
kmem_cache_free(squashfs_inode_cachep, squashfs_i(inode));
|
||||
}
|
||||
|
||||
|
||||
static struct file_system_type squashfs_fs_type = {
|
||||
.owner = THIS_MODULE,
|
||||
.name = "squashfs",
|
||||
.get_sb = squashfs_get_sb,
|
||||
.kill_sb = kill_block_super,
|
||||
.fs_flags = FS_REQUIRES_DEV
|
||||
};
|
||||
|
||||
static struct super_operations squashfs_super_ops = {
|
||||
.alloc_inode = squashfs_alloc_inode,
|
||||
.destroy_inode = squashfs_destroy_inode,
|
||||
.statfs = squashfs_statfs,
|
||||
.put_super = squashfs_put_super,
|
||||
.remount_fs = squashfs_remount
|
||||
};
|
||||
|
||||
module_init(init_squashfs_fs);
|
||||
module_exit(exit_squashfs_fs);
|
||||
MODULE_DESCRIPTION("squashfs 4.0, a compressed read-only filesystem");
|
||||
MODULE_AUTHOR("Phillip Lougher <phillip@lougher.demon.co.uk>");
|
||||
MODULE_LICENSE("GPL");
|
||||
|
|
@ -0,0 +1,118 @@
|
|||
/*
|
||||
* Squashfs - a compressed read only filesystem for Linux
|
||||
*
|
||||
* Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008
|
||||
* Phillip Lougher <phillip@lougher.demon.co.uk>
|
||||
*
|
||||
* This program is free software; you can redistribute it and/or
|
||||
* modify it under the terms of the GNU General Public License
|
||||
* as published by the Free Software Foundation; either version 2,
|
||||
* or (at your option) any later version.
|
||||
*
|
||||
* This program is distributed in the hope that it will be useful,
|
||||
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||||
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
||||
* GNU General Public License for more details.
|
||||
*
|
||||
* You should have received a copy of the GNU General Public License
|
||||
* along with this program; if not, write to the Free Software
|
||||
* Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
|
||||
*
|
||||
* symlink.c
|
||||
*/
|
||||
|
||||
/*
|
||||
* This file implements code to handle symbolic links.
|
||||
*
|
||||
* The data contents of symbolic links are stored inside the symbolic
|
||||
* link inode within the inode table. This allows the normally small symbolic
|
||||
* link to be compressed as part of the inode table, achieving much greater
|
||||
* compression than if the symbolic link was compressed individually.
|
||||
*/
|
||||
|
||||
#include <linux/fs.h>
|
||||
#include <linux/vfs.h>
|
||||
#include <linux/kernel.h>
|
||||
#include <linux/slab.h>
|
||||
#include <linux/string.h>
|
||||
#include <linux/pagemap.h>
|
||||
#include <linux/zlib.h>
|
||||
|
||||
#include "squashfs_fs.h"
|
||||
#include "squashfs_fs_sb.h"
|
||||
#include "squashfs_fs_i.h"
|
||||
#include "squashfs.h"
|
||||
|
||||
static int squashfs_symlink_readpage(struct file *file, struct page *page)
|
||||
{
|
||||
struct inode *inode = page->mapping->host;
|
||||
struct super_block *sb = inode->i_sb;
|
||||
struct squashfs_sb_info *msblk = sb->s_fs_info;
|
||||
int index = page->index << PAGE_CACHE_SHIFT;
|
||||
u64 block = squashfs_i(inode)->start;
|
||||
int offset = squashfs_i(inode)->offset;
|
||||
int length = min_t(int, i_size_read(inode) - index, PAGE_CACHE_SIZE);
|
||||
int bytes, copied;
|
||||
void *pageaddr;
|
||||
struct squashfs_cache_entry *entry;
|
||||
|
||||
TRACE("Entered squashfs_symlink_readpage, page index %ld, start block "
|
||||
"%llx, offset %x\n", page->index, block, offset);
|
||||
|
||||
/*
|
||||
* Skip index bytes into symlink metadata.
|
||||
*/
|
||||
if (index) {
|
||||
bytes = squashfs_read_metadata(sb, NULL, &block, &offset,
|
||||
index);
|
||||
if (bytes < 0) {
|
||||
ERROR("Unable to read symlink [%llx:%x]\n",
|
||||
squashfs_i(inode)->start,
|
||||
squashfs_i(inode)->offset);
|
||||
goto error_out;
|
||||
}
|
||||
}
|
||||
|
||||
/*
|
||||
* Read length bytes from symlink metadata. Squashfs_read_metadata
|
||||
* is not used here because it can sleep and we want to use
|
||||
* kmap_atomic to map the page. Instead call the underlying
|
||||
* squashfs_cache_get routine. As length bytes may overlap metadata
|
||||
* blocks, we may need to call squashfs_cache_get multiple times.
|
||||
*/
|
||||
for (bytes = 0; bytes < length; offset = 0, bytes += copied) {
|
||||
entry = squashfs_cache_get(sb, msblk->block_cache, block, 0);
|
||||
if (entry->error) {
|
||||
ERROR("Unable to read symlink [%llx:%x]\n",
|
||||
squashfs_i(inode)->start,
|
||||
squashfs_i(inode)->offset);
|
||||
squashfs_cache_put(entry);
|
||||
goto error_out;
|
||||
}
|
||||
|
||||
pageaddr = kmap_atomic(page, KM_USER0);
|
||||
copied = squashfs_copy_data(pageaddr + bytes, entry, offset,
|
||||
length - bytes);
|
||||
if (copied == length - bytes)
|
||||
memset(pageaddr + length, 0, PAGE_CACHE_SIZE - length);
|
||||
else
|
||||
block = entry->next_index;
|
||||
kunmap_atomic(pageaddr, KM_USER0);
|
||||
squashfs_cache_put(entry);
|
||||
}
|
||||
|
||||
flush_dcache_page(page);
|
||||
SetPageUptodate(page);
|
||||
unlock_page(page);
|
||||
return 0;
|
||||
|
||||
error_out:
|
||||
SetPageError(page);
|
||||
unlock_page(page);
|
||||
return 0;
|
||||
}
|
||||
|
||||
|
||||
const struct address_space_operations squashfs_symlink_aops = {
|
||||
.readpage = squashfs_symlink_readpage
|
||||
};
|
||||
|
|
@ -9,6 +9,7 @@
|
|||
#include <linux/string.h>
|
||||
|
||||
#include "do_mounts.h"
|
||||
#include "../fs/squashfs/squashfs_fs.h"
|
||||
|
||||
int __initdata rd_prompt = 1;/* 1 = prompt for RAM disk, 0 = don't prompt */
|
||||
|
||||
|
|
@ -41,6 +42,7 @@ static int __init crd_load(int in_fd, int out_fd);
|
|||
* ext2
|
||||
* romfs
|
||||
* cramfs
|
||||
* squashfs
|
||||
* gzip
|
||||
*/
|
||||
static int __init
|
||||
|
|
@ -51,6 +53,7 @@ identify_ramdisk_image(int fd, int start_block)
|
|||
struct ext2_super_block *ext2sb;
|
||||
struct romfs_super_block *romfsb;
|
||||
struct cramfs_super *cramfsb;
|
||||
struct squashfs_super_block *squashfsb;
|
||||
int nblocks = -1;
|
||||
unsigned char *buf;
|
||||
|
||||
|
|
@ -62,6 +65,7 @@ identify_ramdisk_image(int fd, int start_block)
|
|||
ext2sb = (struct ext2_super_block *) buf;
|
||||
romfsb = (struct romfs_super_block *) buf;
|
||||
cramfsb = (struct cramfs_super *) buf;
|
||||
squashfsb = (struct squashfs_super_block *) buf;
|
||||
memset(buf, 0xe5, size);
|
||||
|
||||
/*
|
||||
|
|
@ -99,6 +103,16 @@ identify_ramdisk_image(int fd, int start_block)
|
|||
goto done;
|
||||
}
|
||||
|
||||
/* squashfs is at block zero too */
|
||||
if (le32_to_cpu(squashfsb->s_magic) == SQUASHFS_MAGIC) {
|
||||
printk(KERN_NOTICE
|
||||
"RAMDISK: squashfs filesystem found at block %d\n",
|
||||
start_block);
|
||||
nblocks = (le64_to_cpu(squashfsb->bytes_used) + BLOCK_SIZE - 1)
|
||||
>> BLOCK_SIZE_BITS;
|
||||
goto done;
|
||||
}
|
||||
|
||||
/*
|
||||
* Read block 1 to test for minix and ext2 superblock
|
||||
*/
|
||||
|
|
|
|||
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