This is a fix of regression, which triggered by ~2.6.16.
Patch with name ufs-directory-and-page-cache-from-blocks-to-pages.patch: in
additional to conversation from block to page cache mechanism added new
checks of directory integrity, one of them that directory entry do not
across directory chunks.
But some kinds of UFS: OpenStep UFS and Apple UFS (looks like these are the
same filesystems) have different directory chunk size, then common
UFSes(BSD and Solaris UFS).
So this patch adds ability to works with variable size of directory chunks,
and set it for ufstype=openstep to right size.
Tested on darwin ufs.
Signed-off-by: Evgeniy Dushistov <dushistov@mail.ru>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In blocks reallocation function sometimes does not update some of
buffer_head::b_blocknr, which may and cause data damage.
Signed-off-by: Evgeniy Dushistov <dushistov@mail.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
During ufs_trunc_direct which is subroutine of ufs::truncate, we try the first
of all free parts of block and then whole blocks. But we calculate size of
block's part to free in the wrong way.
This may cause bad update of used blocks and fragments statistic, and you can
got report that you have free 32T on 1Gb partition.
Signed-off-by: Evgeniy Dushistov <dushistov@mail.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
These series of patches result of UFS1 write support stress testing, like
running fsx-linux, untar and build linux kernel etc
We pass from ufs::get_block_t to levels below: pointer to the current page, to
make possible things like reallocation of blocks on the fly, and we also uses
this pointer for indication, what actually we allocate data block or meta data
block, but currently we make decision about what we allocate on the wrong
level, this may and cause oops if we allocate blocks in some special order.
Signed-off-by: Evgeniy Dushistov <dushistov@mail.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Looks like this is the problem, which point Al Viro some time ago:
ufs's get_block callback allocates 16k of disk at a time, and links that
entire 16k into the file's metadata. But because get_block is called for only
a single buffer_head (a 2k buffer_head in this case?) we are only able to tell
the VFS that this 2k is buffer_new().
So when ufs_getfrag_block() is later called to map some more data in the file,
and when that data resides within the remaining 14k of this fragment,
ufs_getfrag_block() will incorrectly return a !buffer_new() buffer_head.
I don't see _right_ way to do nullification of whole block, if use inode
page cache, some pages may be outside of inode limits (inode size), and
will be lost; if use blockdev page cache it is possible to zero real data,
if later inode page cache will be used.
The simpliest way, as can I see usage of block device page cache, but not only
mark dirty, but also sync it during "nullification". I use my simple tests
collection, which I used for check that create,open,write,read,close works on
ufs, and I see that this patch makes ufs code 18% slower then before.
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
It would very lame to get buffer overflow via one of the following.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Dave Kleikamp <shaggy@austin.ibm.com>
Cc: Mark Fasheh <mark.fasheh@oracle.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Replace all uses of kmem_cache_t with struct kmem_cache.
The patch was generated using the following script:
#!/bin/sh
#
# Replace one string by another in all the kernel sources.
#
set -e
for file in `find * -name "*.c" -o -name "*.h"|xargs grep -l $1`; do
quilt add $file
sed -e "1,\$s/$1/$2/g" $file >/tmp/$$
mv /tmp/$$ $file
quilt refresh
done
The script was run like this
sh replace kmem_cache_t "struct kmem_cache"
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
SLAB_KERNEL is an alias of GFP_KERNEL.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
When a filesystem decrements i_nlink to zero, it means that a write must be
performed in order to drop the inode from the filesystem.
We're shortly going to have keep filesystems from being remounted r/o between
the time that this i_nlink decrement and that write occurs.
So, add a little helper function to do the decrements. We'll tie into it in a
bit to note when i_nlink hits zero.
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch cleans up generic_file_*_read/write() interfaces. Christoph
Hellwig gave me the idea for this clean ups.
In a nutshell, all filesystems should set .aio_read/.aio_write methods and use
do_sync_read/ do_sync_write() as their .read/.write methods. This allows us
to cleanup all variants of generic_file_* routines.
Final available interfaces:
generic_file_aio_read() - read handler
generic_file_aio_write() - write handler
generic_file_aio_write_nolock() - no lock write handler
__generic_file_aio_write_nolock() - internal worker routine
Signed-off-by: Badari Pulavarty <pbadari@us.ibm.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This eliminates the i_blksize field from struct inode. Filesystems that want
to provide a per-inode st_blksize can do so by providing their own getattr
routine instead of using the generic_fillattr() function.
Note that some filesystems were providing pretty much random (and incorrect)
values for i_blksize.
[bunk@stusta.de: cleanup]
[akpm@osdl.org: generic_fillattr() fix]
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* Rougly half of callers already do it by not checking return value
* Code in drivers/acpi/osl.c does the following to be sure:
(void)kmem_cache_destroy(cache);
* Those who check it printk something, however, slab_error already printed
the name of failed cache.
* XFS BUGs on failed kmem_cache_destroy which is not the decision
low-level filesystem driver should make. Converted to ignore.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
1) When we allocated last fragment in ufs_truncate, we read page, check
if block mapped to address, and if not trying to allocate it. This is
wrong behaviour, fragment may be NOT allocated, but mapped, this
happened because of "block map" function not checked allocated fragment
or not, it just take address of the first fragment in the block, add
offset of fragment and return result, this is correct behaviour in
almost all situation except call from ufs_truncate.
2) Almost all implementation of UFS, which I can investigate have such
"defect": if you have full disk, and try truncate file, for example 3GB
to 2MB, and have hole in this region, truncate return -ENOSPC. I tried
evade from this problem, but "block allocation" algorithm is tied to
right value of i_lastfrag, and fix of this corner case may slow down of
ordinaries scenarios, so this patch makes behavior of "truncate"
operations similar to what other UFS implementations do.
Signed-off-by: Evgeniy Dushistov <dushistov@mail.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
On UFS, this scenario:
open(O_TRUNC)
lseek(1024 * 1024 * 80)
write("A")
lseek(1024 * 2)
write("A")
may cause access to invalid address.
This happened because of "goal" is calculated in wrong way in block
allocation path, as I see this problem exists also in 2.4.
We use construction like this i_data[lastfrag], i_data array of pointers to
direct blocks, indirect and so on, it has ceratain size ~20 elements, and
lastfrag may have value for example 40000.
Also this patch fixes related to handling such scenario issues, wrong
zeroing metadata, in case of block(not fragment) allocation, and wrong goal
calculation, when we allocate block
Signed-off-by: Evgeniy Dushistov <dushistov@mail.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
ufs_get_locked_page is called twice in ufs code, one time in ufs_truncate
path(we allocated last block), and another time when fragments are
reallocated. In ideal world in the second case on allocation/free block
layer we should not know that things like `truncate' exists, but now with
such crutch like ufs_get_locked_page we can (or should?) skip truncated
pages.
Signed-off-by: Evgeniy Dushistov <dushistov@mail.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
As discussed earlier:
http://lkml.org/lkml/2006/6/28/136
this patch fixes such issue:
`ufs_get_locked_page' takes page from cache
after that `vmtruncate' takes page and deletes it from cache
`ufs_get_locked_page' locks page, and reports about EIO error.
Also because of find_lock_page always return valid page or NULL, we have no
need to check it if page not NULL.
Signed-off-by: Evgeniy Dushistov <dushistov@mail.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
ufs_symlink, in one of its error paths, calls unlock_kernel without ever
having called lock_kernel(); fix this by creating and jumping to a new
label out_notlocked rather than the out label used after calling
lock_kernel().
Signed-off-by: Josh Triplett <josh@freedesktop.org>
Cc: Evgeniy Dushistov <dushistov@mail.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The quota code plays interesting games with the lock ordering; to quote Jan:
| i_mutex of inode containing quota file is acquired after all other
| quota locks. i_mutex of all other inodes is acquired before quota
| locks. Quota code makes sure (by resetting inode operations and
| setting special flag on inode) that noone tries to enter quota code
| while holding i_mutex on a quota file...
The good news is that all of this special case i_mutex grabbing happens in the
(per filesystem) low level quota write function. For this special case we
need a new I_MUTEX_* nesting level, since this just entirely outside any of
the regular VFS locking rules for i_mutex. I trust Jan on his blue eyes that
this is not ever going to deadlock; and based on that the patch below is what
it takes to inform lockdep of these very interesting new locking rules.
The new locking rule for the I_MUTEX_QUOTA nesting level is that this is the
deepest possible level of nesting for i_mutex, and that this only should be
used in quota write (and possibly read) function of filesystems. This makes
the lock ordering of the I_MUTEX_* levels:
I_MUTEX_PARENT -> I_MUTEX_CHILD -> I_MUTEX_NORMAL -> I_MUTEX_QUOTA
Has no effect on non-lockdep kernels.
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: Jan Kara <jack@ucw.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch fixes buggy behaviour of UFS
in such kind of scenario:
open(, O_TRUNC...)
ftruncate(, 1024)
ftruncate(, 0)
Such a scenario causes ufs_panic and remount read-only. This happen
because of according to specification UFS should always allocate block for
last byte, and many parts of our implementation rely on this, but
`ufs_truncate' doesn't care about this.
To make possible return error code and to know about old size, this patch
removes `truncate' from ufs inode_operations and uses `setattr' method to
call ufs_truncate.
Signed-off-by: Evgeniy Dushistov <dushistov@mail.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
fs/ufs/inode.c: In function `ufs_frag_map':
fs/ufs/inode.c:101: warning: long long unsigned int format, u64 arg (arg 4)
fs/ufs/inode.c: In function `ufs_getfrag_block':
fs/ufs/inode.c:432: warning: long long unsigned int format, u64 arg (arg 2)
Cc: Evgeniy Dushistov <dushistov@mail.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Same as with already do with the file operations: keep them in .rodata and
prevents people from doing runtime patching.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: Steven French <sfrench@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Add missed ufsi->i_dir_start_lookup initialization in ufs_read_inode in
UFS2 case. Also it cleans ufs_read_inode function to prevent such kind of
situation in the future: it move depend on UFS type parts of code into
separate functions and leaves in ufs_read_inode only generic code. It
cleans code and avoids duplication.
Signed-off-by: Evgeniy Dushistov <dushistov@mail.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Make two needlessly global functions static.
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
In ufs code there is function: ubh_ll_rw_block, it has parameter how many
ufs_buffer_head it should handle, but it always called with "1" on the place
of this parameter. This patch removes unused parameter of "ubh_ll_wr_block".
Signed-off-by: Evgeniy Dushistov <dushistov@mail.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
ufs super block contains some statistic about file systems, like amount of
directories, free blocks, inodes and so on.
UFS1 hold this information in one location and uses 32bit integers for such
information, UFS2 hold statistic in another location and uses 64bit integers.
There is transition variant, if UFS1 has type 44BSD and flags field in super
block has some special value this mean that we work with statistic like UFS2
does. and this also means that nobody care about old(UFS1) statistic.
So if start fsck against such file system, after usage linux ufs driver, it
found error: at now only UFS1 like statistic is updated.
This patch should fix this. Also it contains some minor cleanup: CodingSytle
and remove unused variables.
Signed-off-by: Evgeniy Dushistov <dushistov@mail.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Presently ufs doesn't support "fsync", this make some applications unhappy,
for example vim. This patch fixes this situation.
Signed-off-by: Evgeniy Dushistov <dushistov@mail.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Super block of UFS usually has size >512, because of fragment size may be 512,
this cause some problems.
Currently, there are two methods to work with ufs super block:
1) split structure which describes ufs super blocks into structures with
size <=512
2) use one structure which describes ufs super block, and hope that array
of "buffer_head" which holds "super block", has such construction:
bh[n]->b_data + bh[n]->b_size == bh[n + 1]->b_data
The second variant may cause some problems in the future, and usage of two
variants cause unnecessary code duplication.
This patch remove the second variant. Also patch contains some CodingStyle
fixes.
Signed-off-by: Evgeniy Dushistov <dushistov@mail.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch fixes two bugs, which introduced by previous patches:
1) Missed "brelse"
2) Sometimes "baseblk" may be wrongly calculated, if i_size is equal to
zero, which lead infinite cycle in "mpage_writepages".
Signed-off-by: Evgeniy Dushistov <dushistov@mail.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
fs/ufs/super.c: In function `ufs_print_super_stuff':
fs/ufs/super.c:103: warning: unsigned int format, different type arg (arg 2) fs/ufs/super.c: In function `ufs2_print_super_stuff': fs/ufs/super.c:147: warning: unsigned int format, different type arg (arg 2) fs/ufs/super.c: In function `ufs_print_cylinder_stuff':
fs/ufs/super.c:175: warning: unsigned int format, different type arg (arg 2)
Cc: Evgeniy Dushistov <dushistov@mail.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Presently if we allocate several "metadata" blocks (pointers to indirect
blocks for example), we fill with zeroes only the first block. This cause
some problems in "truncate" function. Also this patch remove some unused
arguments from several functions and add comments.
Signed-off-by: Evgeniy Dushistov <dushistov@mail.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
ufs_free_blocks function looks now in so way:
if (err)
goto failed;
lock_super();
failed:
unlock_super();
So if error happen we'll unlock not locked super.
Signed-off-by: Evgeniy Dushistov <dushistov@mail.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
At now UFS code uses DQUOT_* mechanism, but it also update inode->i_blocks
manually, this cause wrong i_blocks value.
Signed-off-by: Evgeniy Dushistov <dushistov@mail.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch make little optimization of ufs_find_entry like "ext2" does. Save
number of page and reuse it again in the next call.
Signed-off-by: Evgeniy Dushistov <dushistov@mail.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Currently to turn on debug mode "user" has to edit ~10 files, to turn off he
has to do it again.
This patch introduce such changes:
1)turn on(off) debug messages via ".config"
2)remove unnecessary duplication of code
3)make "UFSD" macros more similar to function
4)fix some compiler warnings
Signed-off-by: Evgeniy Dushistov <dushistov@mail.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The writing to UFS file system with block/fragment!=8 may cause bogus
behaviour. The problem in "ufs_bitmap_search" function, which doesn't work
correctly in "block/fragment!=8" case. The idea is stolen from BSD code.
Signed-off-by: Evgeniy Dushistov <dushistov@mail.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
There are two ugly macros in ufs code:
#define UCPI_UBH ((struct ufs_buffer_head *)ucpi)
#define USPI_UBH ((struct ufs_buffer_head *)uspi)
when uspi looks like
struct {
struct ufs_buffer_head ;
}
and USPI_UBH has some sence,
ucpi looks like
struct {
struct not_ufs_buffer_head;
}
To prevent bugs in future, this patch convert macros to inline function and
fix "ucpi" structure.
Signed-off-by: Evgeniy Dushistov <dushistov@mail.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Change function in fs/ufs/dir.c and fs/ufs/namei.c to work with pages
instead of straight work with blocks. It fixed such bugs:
* for i in `seq 1 1000`; do touch $i; done - crash system
* mkdir create directory without "." and ".." entries
Signed-off-by: Evgeniy Dushistov <dushistov@mail.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This series of patches finished "bugs fixing" mentioned
here http://lkml.org/lkml/2006/1/31/275 .
The main bugs:
* for i in `seq 1 1000`; do touch $i; done - crash system
* mkdir create directory without "." and ".." entries
The suggested solution is work with page cache instead of straight work
with blocks. Such solution has following advantages
* reduce code size and its complexity
* some global locks go away
* fix bugs
The most part of code is stolen from ext2, because of it has similar
directory structure.
Patches testes with UFS1 and UFS2 file systems.
This patch installs i_mapping->a_ops for directory inodes and removes some
duplicated code.
Signed-off-by: Evgeniy Dushistov <dushistov@mail.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
First of all some necessary notes about UFS by it self: To avoid waste of disk
space the tail of file consists not from blocks (which is ordinary big enough,
16K usually), it consists from fragments(which is ordinary 2K). When file is
growing its tail occupy 1 fragment, 2 fragments... At some stage decision to
allocate whole block is made and all fragments are moved to one block.
How this situation was handled before:
ufs_prepare_write
->block_prepare_write
->ufs_getfrag_block
->...
->ufs_new_fragments:
bh = sb_bread
bh->b_blocknr = result + i;
mark_buffer_dirty (bh);
This is wrong solution, because:
- it didn't take into consideration that there is another cache: "inode page
cache"
- because of sb_getblk uses not b_blocknr, (it uses page->index) to find
certain block, this breaks sb_getblk.
How this situation is handled now: we go though all "page inode cache", if
there are no such page in cache we load it into cache, and change b_blocknr.
Signed-off-by: Evgeniy Dushistov <dushistov@mail.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* After block allocation, we map it on the same "address" as 8 others
blocks
* We nullify block several times: once in ufs/block.c and once in
block_*write_full_page, and use different "caches" for this.
Signed-off-by: Evgeniy Dushistov <dushistov@mail.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Currently, ufs write support have two sets of problems: work with files and
work with directories.
This series of patches should solve the first problem.
This patch is similar to http://lkml.org/lkml/2006/1/17/61 this patch
complements it.
The situation the same: in ufs_trunc_(not direct), we read block, check if
count of links to it is equal to one, if so we finish cycle, if not
continue. Because of "count of links" always >=2 this operation cause
infinite cycle and hang up the kernel.
Signed-off-by: Evgeniy Dushistov <dushistov@mail.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Give the statfs superblock operation a dentry pointer rather than a superblock
pointer.
This complements the get_sb() patch. That reduced the significance of
sb->s_root, allowing NFS to place a fake root there. However, NFS does
require a dentry to use as a target for the statfs operation. This permits
the root in the vfsmount to be used instead.
linux/mount.h has been added where necessary to make allyesconfig build
successfully.
Interest has also been expressed for use with the FUSE and XFS filesystems.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: Nathan Scott <nathans@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Extend the get_sb() filesystem operation to take an extra argument that
permits the VFS to pass in the target vfsmount that defines the mountpoint.
The filesystem is then required to manually set the superblock and root dentry
pointers. For most filesystems, this should be done with simple_set_mnt()
which will set the superblock pointer and then set the root dentry to the
superblock's s_root (as per the old default behaviour).
The get_sb() op now returns an integer as there's now no need to return the
superblock pointer.
This patch permits a superblock to be implicitly shared amongst several mount
points, such as can be done with NFS to avoid potential inode aliasing. In
such a case, simple_set_mnt() would not be called, and instead the mnt_root
and mnt_sb would be set directly.
The patch also makes the following changes:
(*) the get_sb_*() convenience functions in the core kernel now take a vfsmount
pointer argument and return an integer, so most filesystems have to change
very little.
(*) If one of the convenience function is not used, then get_sb() should
normally call simple_set_mnt() to instantiate the vfsmount. This will
always return 0, and so can be tail-called from get_sb().
(*) generic_shutdown_super() now calls shrink_dcache_sb() to clean up the
dcache upon superblock destruction rather than shrink_dcache_anon().
This is required because the superblock may now have multiple trees that
aren't actually bound to s_root, but that still need to be cleaned up. The
currently called functions assume that the whole tree is rooted at s_root,
and that anonymous dentries are not the roots of trees which results in
dentries being left unculled.
However, with the way NFS superblock sharing are currently set to be
implemented, these assumptions are violated: the root of the filesystem is
simply a dummy dentry and inode (the real inode for '/' may well be
inaccessible), and all the vfsmounts are rooted on anonymous[*] dentries
with child trees.
[*] Anonymous until discovered from another tree.
(*) The documentation has been adjusted, including the additional bit of
changing ext2_* into foo_* in the documentation.
[akpm@osdl.org: convert ipath_fs, do other stuff]
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: Nathan Scott <nathans@sgi.com>
Cc: Roland Dreier <rolandd@cisco.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This is a conversion to make the various file_operations structs in fs/
const. Basically a regexp job, with a few manual fixups
The goal is both to increase correctness (harder to accidentally write to
shared datastructures) and reducing the false sharing of cachelines with
things that get dirty in .data (while .rodata is nicely read only and thus
cache clean)
Signed-off-by: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Evgeniy Dushistov
Josef Sipek
Mariusz Kozlowski
Alexey Dobriyan
Christoph Lameter
Al Viro
Dave Hansen
Badari Pulavarty
Theodore Ts'o
Panagiotis Issaris
Josh Triplett
Arjan van de Ven
Jörn Engel
Andrew Morton
Christoph Hellwig
Adrian Bunk
David Howells
Arjan van de Ven
Michael Owen