Currently ext4 direct IO handling is split between ext4_ext_direct_IO()
and ext4_ind_direct_IO(). However the extent based function calls into
the indirect based one for some cases and for example it is not able to
handle file extending. Previously it was not also properly handling
retries in case of ENOSPC errors. With DAX things would get even more
contrieved so just refactor the direct IO code and instead of indirect /
extent split do the split to read vs writes.
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
ext4_dax_get_blocks() was accidentally omitted fixing get blocks
handlers to properly handle transient ENOSPC errors. Fix it now to use
ext4_get_blocks_trans() helper which takes care of these errors.
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
In ext4, there is a race condition between changing inode journal mode
and ext4_writepages(). While ext4_writepages() is executed on a
non-journalled mode inode, the inode's journal mode could be enabled
by ioctl() and then, some pages dirtied after switching the journal
mode will be still exposed to ext4_writepages() in non-journaled mode.
To resolve this problem, we use fs-wide per-cpu rw semaphore by Jan
Kara's suggestion because we don't want to waste ext4_inode_info's
space for this extra rare case.
Signed-off-by: Daeho Jeong <daeho.jeong@samsung.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>
We already allocate delalloc blocks before changing the inode mode into
"per-file data journal" mode to prevent delalloc blocks from remaining
not allocated, but another issue concerned with "BH_Unwritten" status
still exists. For example, by fallocate(), several buffers' status
change into "BH_Unwritten", but these buffers cannot be processed by
ext4_alloc_da_blocks(). So, they still remain in unwritten status after
per-file data journaling is enabled and they cannot be changed into
written status any more and, if they are journaled and eventually
checkpointed, these unwritten buffer will cause a kernel panic by the
below BUG_ON() function of submit_bh_wbc() when they are submitted
during checkpointing.
static int submit_bh_wbc(int rw, struct buffer_head *bh,...
{
...
BUG_ON(buffer_unwritten(bh));
Moreover, when "dioread_nolock" option is enabled, the status of a
buffer is changed into "BH_Unwritten" after write_begin() completes and
the "BH_Unwritten" status will be cleared after I/O is done. Therefore,
if a buffer's status is changed into unwrutten but the buffer's I/O is
not submitted and completed, it can cause the same problem after
enabling per-file data journaling. You can easily generate this bug by
executing the following command.
./kvm-xfstests -C 10000 -m nodelalloc,dioread_nolock generic/269
To resolve these problems and define a boundary between the previous
mode and per-file data journaling mode, we need to flush and wait all
the I/O of buffers of a file before enabling per-file data journaling
of the file.
Signed-off-by: Daeho Jeong <daeho.jeong@samsung.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>
Currently we ask jbd2 to write all dirty allocated buffers before
committing a transaction when doing writeback of delay allocated blocks.
However this is unnecessary since we move all pages to writeback state
before dropping a transaction handle and then submit all the necessary
IO. We still need the transaction commit to wait for all the outstanding
writeback before flushing disk caches during transaction commit to avoid
data exposure issues though. Use the new jbd2 capability and ask it to
only wait for outstanding writeback during transaction commit when
writing back data in ext4_writepages().
Tested-by: "HUANG Weller (CM/ESW12-CN)" <Weller.Huang@cn.bosch.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
This flag is just duplicating what ext4_should_order_data() tells you
and is used in a single place. Furthermore it doesn't reflect changes to
inode data journalling flag so it may be possibly misleading. Just
remove it.
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Huang has reported that in his powerfail testing he is seeing stale
block contents in some of recently allocated blocks although he mounts
ext4 in data=ordered mode. After some investigation I have found out
that indeed when delayed allocation is used, we don't add inode to
transaction's list of inodes needing flushing before commit. Originally
we were doing that but commit f3b59291a6 removed the logic with a
flawed argument that it is not needed.
The problem is that although for delayed allocated blocks we write their
contents immediately after allocating them, there is no guarantee that
the IO scheduler or device doesn't reorder things and thus transaction
allocating blocks and attaching them to inode can reach stable storage
before actual block contents. Actually whenever we attach freshly
allocated blocks to inode using a written extent, we should add inode to
transaction's ordered inode list to make sure we properly wait for block
contents to be written before committing the transaction. So that is
what we do in this patch. This also handles other cases where stale data
exposure was possible - like filling hole via mmap in
data=ordered,nodelalloc mode.
The only exception to the above rule are extending direct IO writes where
blkdev_direct_IO() waits for IO to complete before increasing i_size and
thus stale data exposure is not possible. For now we don't complicate
the code with optimizing this special case since the overhead is pretty
low. In case this is observed to be a performance problem we can always
handle it using a special flag to ext4_map_blocks().
CC: stable@vger.kernel.org
Fixes: f3b59291a6
Reported-by: "HUANG Weller (CM/ESW12-CN)" <Weller.Huang@cn.bosch.com>
Tested-by: "HUANG Weller (CM/ESW12-CN)" <Weller.Huang@cn.bosch.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
(badly behaved) dentry code in various file systems. These have been
reviewed by Al and the respective file system mtinainers and are going
through the ext4 tree for convenience.
This also has a few ext4 encryption bug fixes that were discovered in
Android testing (yes, we will need to get these sync'ed up with the
fs/crypto code; I'll take care of that). It also has some bug fixes
and a change to ignore the legacy quota options to allow for xfstests
regression testing of ext4's internal quota feature and to be more
consistent with how xfs handles this case.
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Merge tag 'ext4_for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4
Pull ext4 bugfixes from Ted Ts'o:
"These changes contains a fix for overlayfs interacting with some
(badly behaved) dentry code in various file systems. These have been
reviewed by Al and the respective file system mtinainers and are going
through the ext4 tree for convenience.
This also has a few ext4 encryption bug fixes that were discovered in
Android testing (yes, we will need to get these sync'ed up with the
fs/crypto code; I'll take care of that). It also has some bug fixes
and a change to ignore the legacy quota options to allow for xfstests
regression testing of ext4's internal quota feature and to be more
consistent with how xfs handles this case"
* tag 'ext4_for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
ext4: ignore quota mount options if the quota feature is enabled
ext4 crypto: fix some error handling
ext4: avoid calling dquot_get_next_id() if quota is not enabled
ext4: retry block allocation for failed DIO and DAX writes
ext4: add lockdep annotations for i_data_sem
ext4: allow readdir()'s of large empty directories to be interrupted
btrfs: fix crash/invalid memory access on fsync when using overlayfs
ext4 crypto: use dget_parent() in ext4_d_revalidate()
ext4: use file_dentry()
ext4: use dget_parent() in ext4_file_open()
nfs: use file_dentry()
fs: add file_dentry()
ext4 crypto: don't let data integrity writebacks fail with ENOMEM
ext4: check if in-inode xattr is corrupted in ext4_expand_extra_isize_ea()
Mostly direct substitution with occasional adjustment or removing
outdated comments.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time
ago with promise that one day it will be possible to implement page
cache with bigger chunks than PAGE_SIZE.
This promise never materialized. And unlikely will.
We have many places where PAGE_CACHE_SIZE assumed to be equal to
PAGE_SIZE. And it's constant source of confusion on whether
PAGE_CACHE_* or PAGE_* constant should be used in a particular case,
especially on the border between fs and mm.
Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much
breakage to be doable.
Let's stop pretending that pages in page cache are special. They are
not.
The changes are pretty straight-forward:
- <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>;
- <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>;
- PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN};
- page_cache_get() -> get_page();
- page_cache_release() -> put_page();
This patch contains automated changes generated with coccinelle using
script below. For some reason, coccinelle doesn't patch header files.
I've called spatch for them manually.
The only adjustment after coccinelle is revert of changes to
PAGE_CAHCE_ALIGN definition: we are going to drop it later.
There are few places in the code where coccinelle didn't reach. I'll
fix them manually in a separate patch. Comments and documentation also
will be addressed with the separate patch.
virtual patch
@@
expression E;
@@
- E << (PAGE_CACHE_SHIFT - PAGE_SHIFT)
+ E
@@
expression E;
@@
- E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT)
+ E
@@
@@
- PAGE_CACHE_SHIFT
+ PAGE_SHIFT
@@
@@
- PAGE_CACHE_SIZE
+ PAGE_SIZE
@@
@@
- PAGE_CACHE_MASK
+ PAGE_MASK
@@
expression E;
@@
- PAGE_CACHE_ALIGN(E)
+ PAGE_ALIGN(E)
@@
expression E;
@@
- page_cache_get(E)
+ get_page(E)
@@
expression E;
@@
- page_cache_release(E)
+ put_page(E)
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently if block allocation for DIO or DAX write fails due to ENOSPC,
we just returned it to userspace. However these ENOSPC errors can be
transient because the transaction freeing blocks has not yet committed.
This demonstrates as failures of generic/102 test when the filesystem is
mounted with 'dax' mount option.
Fix the problem by properly retrying the allocation in case of ENOSPC
error in get blocks functions used for direct IO.
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Tested-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Change summary:
o error propagation for direct IO failures fixes for both XFS and ext4
o new quota interfaces and XFS implementation for iterating all the quota IDs
in the filesystem
o locking fixes for real-time device extent allocation
o reduction of duplicate information in the xfs and vfs inode, saving roughly
100 bytes of memory per cached inode.
o buffer flag cleanup
o rework of the writepage code to use the generic write clustering mechanisms
o several fixes for inode flag based DAX enablement
o rework of remount option parsing
o compile time verification of on-disk format structure sizes
o delayed allocation reservation overrun fixes
o lots of little error handling fixes
o small memory leak fixes
o enable xfsaild freezing again
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Merge tag 'xfs-for-linus-4.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/dgc/linux-xfs
Pull xfs updates from Dave Chinner:
"There's quite a lot in this request, and there's some cross-over with
ext4, dax and quota code due to the nature of the changes being made.
As for the rest of the XFS changes, there are lots of little things
all over the place, which add up to a lot of changes in the end.
The major changes are that we've reduced the size of the struct
xfs_inode by ~100 bytes (gives an inode cache footprint reduction of
>10%), the writepage code now only does a single set of mapping tree
lockups so uses less CPU, delayed allocation reservations won't
overrun under random write loads anymore, and we added compile time
verification for on-disk structure sizes so we find out when a commit
or platform/compiler change breaks the on disk structure as early as
possible.
Change summary:
- error propagation for direct IO failures fixes for both XFS and
ext4
- new quota interfaces and XFS implementation for iterating all the
quota IDs in the filesystem
- locking fixes for real-time device extent allocation
- reduction of duplicate information in the xfs and vfs inode, saving
roughly 100 bytes of memory per cached inode.
- buffer flag cleanup
- rework of the writepage code to use the generic write clustering
mechanisms
- several fixes for inode flag based DAX enablement
- rework of remount option parsing
- compile time verification of on-disk format structure sizes
- delayed allocation reservation overrun fixes
- lots of little error handling fixes
- small memory leak fixes
- enable xfsaild freezing again"
* tag 'xfs-for-linus-4.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/dgc/linux-xfs: (66 commits)
xfs: always set rvalp in xfs_dir2_node_trim_free
xfs: ensure committed is initialized in xfs_trans_roll
xfs: borrow indirect blocks from freed extent when available
xfs: refactor delalloc indlen reservation split into helper
xfs: update freeblocks counter after extent deletion
xfs: debug mode forced buffered write failure
xfs: remove impossible condition
xfs: check sizes of XFS on-disk structures at compile time
xfs: ioends require logically contiguous file offsets
xfs: use named array initializers for log item dumping
xfs: fix computation of inode btree maxlevels
xfs: reinitialise per-AG structures if geometry changes during recovery
xfs: remove xfs_trans_get_block_res
xfs: fix up inode32/64 (re)mount handling
xfs: fix format specifier , should be %llx and not %llu
xfs: sanitize remount options
xfs: convert mount option parsing to tokens
xfs: fix two memory leaks in xfs_attr_list.c error paths
xfs: XFS_DIFLAG2_DAX limited by PAGE_SIZE
xfs: dynamically switch modes when XFS_DIFLAG2_DAX is set/cleared
...
improvements, plus a lot of clean ups and bug fixes.
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Merge tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4
Pull ext4 updates from Ted Ts'o:
"Performance improvements in SEEK_DATA and xattr scalability
improvements, plus a lot of clean ups and bug fixes"
* tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (38 commits)
ext4: clean up error handling in the MMP support
jbd2: do not fail journal because of frozen_buffer allocation failure
ext4: use __GFP_NOFAIL in ext4_free_blocks()
ext4: fix compile error while opening the macro DOUBLE_CHECK
ext4: print ext4 mount option data_err=abort correctly
ext4: fix NULL pointer dereference in ext4_mark_inode_dirty()
ext4: drop unneeded BUFFER_TRACE in ext4_delete_inline_entry()
ext4: fix misspellings in comments.
jbd2: fix FS corruption possibility in jbd2_journal_destroy() on umount path
ext4: more efficient SEEK_DATA implementation
ext4: cleanup handling of bh->b_state in DAX mmap
ext4: return hole from ext4_map_blocks()
ext4: factor out determining of hole size
ext4: fix setting of referenced bit in ext4_es_lookup_extent()
ext4: remove i_ioend_count
ext4: simplify io_end handling for AIO DIO
ext4: move trans handling and completion deferal out of _ext4_get_block
ext4: rename and split get blocks functions
ext4: use i_mutex to serialize unaligned AIO DIO
ext4: pack ioend structure better
...
ext4_reserve_inode_write() in ext4_mark_inode_dirty() could fail on
error (e.g. EIO) and iloc.bh can be NULL in this case. But the error is
ignored in the following "if" condition and ext4_expand_extra_isize()
might be called with NULL iloc.bh set, which triggers NULL pointer
dereference.
This is uncovered by commit 8b4953e13f ("ext4: reserve code points for
the project quota feature"), which enlarges the ext4_inode size, and
run the following script on new kernel but with old mke2fs:
#/bin/bash
mnt=/mnt/ext4
devname=ext4-error
dev=/dev/mapper/$devname
fsimg=/home/fs.img
trap cleanup 0 1 2 3 9 15
cleanup()
{
umount $mnt >/dev/null 2>&1
dmsetup remove $devname
losetup -d $backend_dev
rm -f $fsimg
exit 0
}
rm -f $fsimg
fallocate -l 1g $fsimg
backend_dev=`losetup -f --show $fsimg`
devsize=`blockdev --getsz $backend_dev`
good_tab="0 $devsize linear $backend_dev 0"
error_tab="0 $devsize error $backend_dev 0"
dmsetup create $devname --table "$good_tab"
mkfs -t ext4 $dev
mount -t ext4 -o errors=continue,strictatime $dev $mnt
dmsetup load $devname --table "$error_tab" && dmsetup resume $devname
echo 3 > /proc/sys/vm/drop_caches
ls -l $mnt
exit 0
[ Patch changed to simplify the function a tiny bit. -- Ted ]
Signed-off-by: Eryu Guan <guaneryu@gmail.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Using SEEK_DATA in a huge sparse file can easily lead to sotflockups as
ext4_seek_data() iterates hole block-by-block. Fix the problem by using
returned hole size from ext4_map_blocks() and thus skip the hole in one
go.
Update also SEEK_HOLE implementation to follow the same pattern as
SEEK_DATA to make future maintenance easier.
Furthermore we add cond_resched() to both ext4_seek_data() and
ext4_seek_hole() to avoid softlockups in case evil user creates huge
fragmented file and we have to go through lots of extents.
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
ext4_dax_mmap_get_block() updates bh->b_state directly instead of using
ext4_update_bh_state(). This is mostly a cosmetic issue since DAX code
always passes on-stack buffer_head but clean this up to make code more
uniform.
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Currently, ext4_map_blocks() just returns 0 when it finds a hole and
allocation is not requested. However we have all the information
available to tell how large the hole actually is and there are callers
of ext4_map_blocks() which would save some block-by-block hole iteration
if they knew this information. So fill in struct ext4_map_blocks even
for holes with the information we have. We keep returning 0 for holes to
maintain backward compatibility of the function.
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
When mapping blocks for direct IO, we allocate io_end structure before
mapping blocks and store pointer to it in the inode. This creates a
requirement that any AIO DIO using io_end must be protected by i_mutex.
This created problems in the past with dioread_nolock mode which was
corrupting io_end pointers. Also io_end is allocated unnecessarily in
case where we don't need to convert any extents (which is a common case
for example when overwriting file).
We fix the problem by allocating io_end only once we return unwritten
extent from block mapping function for AIO DIO (so we can save some
pointless io_end allocations) and we pass pointer to it in bh->b_private
which generic DIO code later passes to our end IO callback. That way we
remove any need for global pointer to io_end structure and thus fix the
races.
The downside of this change is that the checking for unwritten IO in
flight in ext4_extents_can_be_merged() is more racy since we now
increment i_unwritten / set EXT4_STATE_DIO_UNWRITTEN only after dropping
i_data_sem. However the check has been racy already before because
ext4_writepages() already increment i_unwritten after dropping
i_data_sem and reserved blocks save us from hitting ENOSPC in the worst
case.
Signed-off-by: Jan Kara <jack@suse.cz>
There is no need to handle starting of a transaction and deferal of DIO
completion in _ext4_get_block() function. We can move this out to get
block functions for direct IO that need it. That way we can add stricter
checks verifying things work as we expect.
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Rename ext4_get_blocks_write() to ext4_get_blocks_unwritten() to better
describe what it does. Also split out get blocks functions for direct
IO. Later we move functionality from _ext4_get_blocks() there. There's no
functional change in this patch.
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
When AIO DIO fails e.g. due to IO error, we must not convert unwritten
extents as that will expose uninitialized data. Handle this case
by clearing unwritten flag from io_end in case of error and thus
preventing extent conversion.
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Previously calls to dax_writeback_mapping_range() for all DAX filesystems
(ext2, ext4 & xfs) were centralized in filemap_write_and_wait_range().
dax_writeback_mapping_range() needs a struct block_device, and it used
to get that from inode->i_sb->s_bdev. This is correct for normal inodes
mounted on ext2, ext4 and XFS filesystems, but is incorrect for DAX raw
block devices and for XFS real-time files.
Instead, call dax_writeback_mapping_range() directly from the filesystem
->writepages function so that it can supply us with a valid block
device. This also fixes DAX code to properly flush caches in response
to sync(2).
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Cc: Al Viro <viro@ftp.linux.org.uk>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Jens Axboe <axboe@fb.com>
Cc: Matthew Wilcox <matthew.r.wilcox@intel.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When S_DAX is set on an inode we assume that if there are pages attached
to the mapping (mapping->nrpages != 0), those pages are clean zero pages
that were used to service reads from holes. Any dirty data associated
with the inode should be in the form of DAX exceptional entries
(mapping->nrexceptional) that is written back via
dax_writeback_mapping_range().
With the current code, though, this isn't always true. For example,
ext2 and ext4 directory inodes can have S_DAX set, but have their dirty
data stored as dirty page cache entries. For these types of inodes,
having S_DAX set doesn't really make sense since their I/O doesn't
actually happen through the DAX code path.
Instead, only allow S_DAX to be set for regular inodes for ext2 and
ext4. This allows us to have strict DAX vs non-DAX paths in the
writeback code.
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Al Viro <viro@ftp.linux.org.uk>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Jens Axboe <axboe@fb.com>
Cc: Matthew Wilcox <matthew.r.wilcox@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Competing overwrite DIO in dioread_nolock mode will just overwrite
pointer to io_end in the inode. This may result in data corruption or
extent conversion happening from IO completion interrupt because we
don't properly set buffer_defer_completion() when unlocked DIO races
with locked DIO to unwritten extent.
Since unlocked DIO doesn't need io_end for anything, just avoid
allocating it and corrupting pointer from inode for locked DIO.
A cleaner fix would be to avoid these games with io_end pointer from the
inode but that requires more intrusive changes so we leave that for
later.
Cc: stable@vger.kernel.org
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
ext4 can update bh->b_state non-atomically in _ext4_get_block() and
ext4_da_get_block_prep(). Usually this is fine since bh is just a
temporary storage for mapping information on stack but in some cases it
can be fully living bh attached to a page. In such case non-atomic
update of bh->b_state can race with an atomic update which then gets
lost. Usually when we are mapping bh and thus updating bh->b_state
non-atomically, nobody else touches the bh and so things work out fine
but there is one case to especially worry about: ext4_finish_bio() uses
BH_Uptodate_Lock on the first bh in the page to synchronize handling of
PageWriteback state. So when blocksize < pagesize, we can be atomically
modifying bh->b_state of a buffer that actually isn't under IO and thus
can race e.g. with delalloc trying to map that buffer. The result is
that we can mistakenly set / clear BH_Uptodate_Lock bit resulting in the
corruption of PageWriteback state or missed unlock of BH_Uptodate_Lock.
Fix the problem by always updating bh->b_state bits atomically.
CC: stable@vger.kernel.org
Reported-by: Nikolay Borisov <kernel@kyup.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
This way we can pass back errors to the file system, and allow for
cleanup required for all direct I/O invocations.
Also allow the ->end_io handlers to return errors on their own, so that
I/O completion errors can be passed on to the callers.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
parallel to mutex_{lock,unlock,trylock,is_locked,lock_nested},
inode_foo(inode) being mutex_foo(&inode->i_mutex).
Please, use those for access to ->i_mutex; over the coming cycle
->i_mutex will become rwsem, with ->lookup() done with it held
only shared.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
encryption fixes from me, and Li Xi's Project Quota commits.
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Merge tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4
Pull ext4 updates from Ted Ts'o:
"Some locking and page fault bug fixes from Jan Kara, some ext4
encryption fixes from me, and Li Xi's Project Quota commits"
* tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
fs: clean up the flags definition in uapi/linux/fs.h
ext4: add FS_IOC_FSSETXATTR/FS_IOC_FSGETXATTR interface support
ext4: add project quota support
ext4: adds project ID support
ext4 crypto: simplify interfaces to directory entry insert functions
ext4 crypto: add missing locking for keyring_key access
ext4: use pre-zeroed blocks for DAX page faults
ext4: implement allocation of pre-zeroed blocks
ext4: provide ext4_issue_zeroout()
ext4: get rid of EXT4_GET_BLOCKS_NO_LOCK flag
ext4: document lock ordering
ext4: fix races of writeback with punch hole and zero range
ext4: fix races between buffered IO and collapse / insert range
ext4: move unlocked dio protection from ext4_alloc_file_blocks()
ext4: fix races between page faults and hole punching
Signed-off-by: Li Xi <lixi@ddn.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Reviewed-by: Jan Kara <jack@suse.cz>
kmap() in page_follow_link_light() needed to go - allowing to hold
an arbitrary number of kmaps for long is a great way to deadlocking
the system.
new helper (inode_nohighmem(inode)) needs to be used for pagecache
symlinks inodes; done for all in-tree cases. page_follow_link_light()
instrumented to yell about anything missed.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Make DAX fault path use pre-zeroed blocks to avoid races with extent
conversion and zeroing when two page faults to the same block happen.
Signed-off-by: Jan Kara <jack@suse.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
DAX page fault path needs to get blocks that are pre-zeroed to avoid
races when two concurrent page faults happen in the same block of a
file. Implement support for this in ext4_map_blocks().
Signed-off-by: Jan Kara <jack@suse.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Create new function ext4_issue_zeroout() to zeroout contiguous (both
logically and physically) part of inode data. We will need to issue
zeroout when extent structure is not readily available and this function
will allow us to do it without making up fake extent structures.
Signed-off-by: Jan Kara <jack@suse.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
When dioread_nolock mode is enabled, we grab i_data_sem in
ext4_ext_direct_IO() and therefore we need to instruct _ext4_get_block()
not to grab i_data_sem again using EXT4_GET_BLOCKS_NO_LOCK. However
holding i_data_sem over overwrite direct IO isn't needed these days. We
have exclusion against truncate / hole punching because we increase
i_dio_count under i_mutex in ext4_ext_direct_IO() so once
ext4_file_write_iter() verifies blocks are allocated & written, they are
guaranteed to stay so during the whole direct IO even after we drop
i_mutex.
So we can just remove this locking abuse and the no longer necessary
EXT4_GET_BLOCKS_NO_LOCK flag.
Signed-off-by: Jan Kara <jack@suse.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
When doing delayed allocation, update of on-disk inode size is postponed
until IO submission time. However hole punch or zero range fallocate
calls can end up discarding the tail page cache page and thus on-disk
inode size would never be properly updated.
Make sure the on-disk inode size is updated before truncating page
cache.
Signed-off-by: Jan Kara <jack@suse.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Currently, page faults and hole punching are completely unsynchronized.
This can result in page fault faulting in a page into a range that we
are punching after truncate_pagecache_range() has been called and thus
we can end up with a page mapped to disk blocks that will be shortly
freed. Filesystem corruption will shortly follow. Note that the same
race is avoided for truncate by checking page fault offset against
i_size but there isn't similar mechanism available for punching holes.
Fix the problem by creating new rw semaphore i_mmap_sem in inode and
grab it for writing over truncate, hole punching, and other functions
removing blocks from extent tree and for read over page faults. We
cannot easily use i_data_sem for this since that ranks below transaction
start and we need something ranking above it so that it can be held over
the whole truncate / hole punching operation. Also remove various
workarounds we had in the code to reduce race window when page fault
could have created pages with stale mapping information.
Signed-off-by: Jan Kara <jack@suse.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
The function currently called "__block_page_mkwrite()" used to be called
"block_page_mkwrite()" until a wrapper for this function was added by:
commit 24da4fab5a ("vfs: Create __block_page_mkwrite() helper passing
error values back")
This wrapper, the current "block_page_mkwrite()", is currently unused.
__block_page_mkwrite() is used directly by ext4, nilfs2 and xfs.
Remove the unused wrapper, rename __block_page_mkwrite() back to
block_page_mkwrite() and update the comment above block_page_mkwrite().
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Jan Kara <jack@suse.com>
Cc: Jan Kara <jack@suse.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Merge second patch-bomb from Andrew Morton:
- most of the rest of MM
- procfs
- lib/ updates
- printk updates
- bitops infrastructure tweaks
- checkpatch updates
- nilfs2 update
- signals
- various other misc bits: coredump, seqfile, kexec, pidns, zlib, ipc,
dma-debug, dma-mapping, ...
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (102 commits)
ipc,msg: drop dst nil validation in copy_msg
include/linux/zutil.h: fix usage example of zlib_adler32()
panic: release stale console lock to always get the logbuf printed out
dma-debug: check nents in dma_sync_sg*
dma-mapping: tidy up dma_parms default handling
pidns: fix set/getpriority and ioprio_set/get in PRIO_USER mode
kexec: use file name as the output message prefix
fs, seqfile: always allow oom killer
seq_file: reuse string_escape_str()
fs/seq_file: use seq_* helpers in seq_hex_dump()
coredump: change zap_threads() and zap_process() to use for_each_thread()
coredump: ensure all coredumping tasks have SIGNAL_GROUP_COREDUMP
signal: remove jffs2_garbage_collect_thread()->allow_signal(SIGCONT)
signal: introduce kernel_signal_stop() to fix jffs2_garbage_collect_thread()
signal: turn dequeue_signal_lock() into kernel_dequeue_signal()
signals: kill block_all_signals() and unblock_all_signals()
nilfs2: fix gcc uninitialized-variable warnings in powerpc build
nilfs2: fix gcc unused-but-set-variable warnings
MAINTAINERS: nilfs2: add header file for tracing
nilfs2: add tracepoints for analyzing reading and writing metadata files
...
There are many places which use mapping_gfp_mask to restrict a more
generic gfp mask which would be used for allocations which are not
directly related to the page cache but they are performed in the same
context.
Let's introduce a helper function which makes the restriction explicit and
easier to track. This patch doesn't introduce any functional changes.
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Michal Hocko <mhocko@suse.com>
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Create separate predicate functions to test/set/clear feature flags,
thereby replacing the wordy old macros. Furthermore, clean out the
places where we open-coded feature tests.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Instead of overloading EIO for CRC errors and corrupt structures,
return the same error codes that XFS returns for the same issues.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
If there is a error while copying data from userspace into the page
cache during a write(2) system call, in data=journal mode, in
ext4_journalled_write_end() were using page_zero_new_buffers() from
fs/buffer.c. Unfortunately, this sets the buffer dirty flag, which is
no good if journalling is enabled. This is a long-standing bug that
goes back for years and years in ext3, but a combination of (a)
data=journal not being very common, (b) in many case it only results
in a warning message. and (c) only very rarely causes the kernel hang,
means that we only really noticed this as a problem when commit
998ef75ddb caused this failure to happen frequently enough to cause
generic/208 to fail when run in data=journal mode.
The fix is to have our own version of this function that doesn't call
mark_dirty_buffer(), since we will end up calling
ext4_handle_dirty_metadata() on the buffer head(s) in questions very
shortly afterwards in ext4_journalled_write_end().
Thanks to Dave Hansen and Linus Torvalds for helping to identify the
root cause of the problem.
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.com>
Since ext4_page_crypto() doesn't need an encryption context (at least
not any more), this allows us to simplify a number function signature
and also allows us to avoid needing to allocate a context in
ext4_block_write_begin(). It also means we no longer need a separate
ext4_decrypt_one() function.
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
In cases where the file system block size is the same as the page
size, and ext4_writepage() is asked to write out a page which is
either has the unwritten bit set in the extent tree, or which does not
yet have a block assigned due to delayed allocation, we can bail out
early and, unlocking the page earlier and avoiding a round trip
through ext4_bio_write_page() with the attendant calls to
set_page_writeback() and redirty_page_for_writeback().
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
DAX wants different semantics from any currently-existing ext4 get_block
callback. Unlike ext4_get_block_write(), it needs to honour the
'create' flag, and unlike ext4_get_block(), it needs to be able to
return unwritten extents. So introduce a new ext4_get_block_dax() which
has those semantics.
We could also change ext4_get_block_write() to honour the 'create' flag,
but that might have consequences on other users that I do not currently
understand.
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In order to handle the !CONFIG_TRANSPARENT_HUGEPAGES case, we need to
return VM_FAULT_FALLBACK from the inlined dax_pmd_fault(), which is
defined in linux/mm.h. Given that we don't want to include <linux/mm.h>
in <linux/fs.h>, the easiest solution is to move the DAX-related
functions to a new header, <linux/dax.h>. We could also have moved
VM_FAULT_* definitions to a new header, or a different header that isn't
quite such a boil-the-ocean header as <linux/mm.h>, but this felt like
the best option.
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Cc: Hillf Danton <dhillf@gmail.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
features and other churn going into 4.2.
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Merge tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4
Pull ext4 updates from Ted Ts'o:
"Pretty much all bug fixes and clean ups for 4.3, after a lot of
features and other churn going into 4.2"
* tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
Revert "ext4: remove block_device_ejected"
ext4: ratelimit the file system mounted message
ext4: silence a format string false positive
ext4: simplify some code in read_mmp_block()
ext4: don't manipulate recovery flag when freezing no-journal fs
jbd2: limit number of reserved credits
ext4 crypto: remove duplicate header file
ext4: update c/mtime on truncate up
jbd2: avoid infinite loop when destroying aborted journal
ext4, jbd2: add REQ_FUA flag when recording an error in the superblock
ext4 crypto: fix spelling typo in comment
ext4 crypto: exit cleanly if ext4_derive_key_aes() fails
ext4: reject journal options for ext2 mounts
ext4: implement cgroup writeback support
ext4: replace ext4_io_submit->io_op with ->io_wbc
ext4 crypto: check for too-short encrypted file names
ext4 crypto: use a jbd2 transaction when adding a crypto policy
jbd2: speedup jbd2_journal_dirty_metadata()
Commit 3da40c7b08 ("ext4: only call ext4_truncate when size <= isize")
introduced a bug that c/mtime is not updated on truncate up.
Fix the issue by setting c/mtime explicitly in the truncate up case.
Note that ftruncate(2) is not affected, so you won't see this bug using
truncate(1) and xfs_io(1).
Signed-off-by: Zirong Lang <zorro.lang@gmail.com>
Signed-off-by: Eryu Guan <guaneryu@gmail.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Jan Kara
Daeho Jeong
Linus Torvalds
Kirill A. Shutemov
Eryu Guan
Ross Zwisler
Jan Kara
Christoph Hellwig
Al Viro
Li Xi
Michal Hocko
Darrick J. Wong
Theodore Ts'o
Matthew Wilcox