ext4: add trace exit in exception path.

Missing trace exit in exception path of ext4_sync_file and
ext4_ind_map_blocks.

Signed-off-by: Zhang Qilong <zhangqilong3@huawei.com>

ext4: add trace exit in exception path.

Missing trace exit in exception path of ext4_sync_file and
ext4_ind_map_blocks.

Signed-off-by: Zhang Qilong <zhangqilong3@huawei.com>
Link: https://lore.kernel.org/r/20200921124738.23352-1-zhangqilong3@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

show more ...

Merge tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4

Pull ext4 updates from Ted Ts'o:
"A lot of bug fixes and cleanups for ext4, including:

Merge tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4

Pull ext4 updates from Ted Ts'o:
"A lot of bug fixes and cleanups for ext4, including:

- Fix performance problems found in dioread_nolock now that it is the
default, caused by transaction leaks.

- Clean up fiemap handling in ext4

- Clean up and refactor multiple block allocator (mballoc) code

- Fix a problem with mballoc with a smaller file systems running out
of blocks because they couldn't properly use blocks that had been
reserved by inode preallocation.

- Fixed a race in ext4_sync_parent() versus rename()

- Simplify the error handling in the extent manipulation code

- Make sure all metadata I/O errors are felected to
ext4_ext_dirty()'s and ext4_make_inode_dirty()'s callers.

- Avoid passing an error pointer to brelse in ext4_xattr_set()

- Fix race which could result to freeing an inode on the dirty last
in data=journal mode.

- Fix refcount handling if ext4_iget() fails

- Fix a crash in generic/019 caused by a corrupted extent node"

* tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (58 commits)
ext4: avoid unnecessary transaction starts during writeback
ext4: don't block for O_DIRECT if IOCB_NOWAIT is set
ext4: remove the access_ok() check in ext4_ioctl_get_es_cache
fs: remove the access_ok() check in ioctl_fiemap
fs: handle FIEMAP_FLAG_SYNC in fiemap_prep
fs: move fiemap range validation into the file systems instances
iomap: fix the iomap_fiemap prototype
fs: move the fiemap definitions out of fs.h
fs: mark __generic_block_fiemap static
ext4: remove the call to fiemap_check_flags in ext4_fiemap
ext4: split _ext4_fiemap
ext4: fix fiemap size checks for bitmap files
ext4: fix EXT4_MAX_LOGICAL_BLOCK macro
add comment for ext4_dir_entry_2 file_type member
jbd2: avoid leaking transaction credits when unreserving handle
ext4: drop ext4_journal_free_reserved()
ext4: mballoc: use lock for checking free blocks while retrying
ext4: mballoc: refactor ext4_mb_good_group()
ext4: mballoc: introduce pcpu seqcnt for freeing PA to improve ENOSPC handling
ext4: mballoc: refactor ext4_mb_discard_preallocations()
...

show more ...

ext4: fix race between ext4_sync_parent() and rename()

'igrab(d_inode(dentry->d_parent))' without holding dentry->d_lock is
broken because without d_lock, d_parent can be concurrently ch

ext4: fix race between ext4_sync_parent() and rename()

'igrab(d_inode(dentry->d_parent))' without holding dentry->d_lock is
broken because without d_lock, d_parent can be concurrently changed due
to a rename(). Then if the old directory is immediately deleted, old
d_parent->inode can be NULL. That causes a NULL dereference in igrab().

To fix this, use dget_parent() to safely grab a reference to the parent
dentry, which pins the inode. This also eliminates the need to use
d_find_any_alias() other than for the initial inode, as we no longer
throw away the dentry at each step.

This is an extremely hard race to hit, but it is possible. Adding a
udelay() in between the reads of ->d_parent and its ->d_inode makes it
reproducible on a no-journal filesystem using the following program:

#include <fcntl.h>
#include <unistd.h>

int main()
{
if (fork()) {
for (;;) {
mkdir("dir1", 0700);
int fd = open("dir1/file", O_RDWR|O_CREAT|O_SYNC);
write(fd, "X", 1);
close(fd);
}
} else {
mkdir("dir2", 0700);
for (;;) {
rename("dir1/file", "dir2/file");
rmdir("dir1");
}
}
}

Fixes: d59729f4e794 ("ext4: fix races in ext4_sync_parent()")
Cc: stable@vger.kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20200506183140.541194-1-ebiggers@kernel.org
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

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block: remove the error_sector argument to blkdev_issue_flush

The argument isn't used by any caller, and drivers don't fill out
bi_sector for flush requests either.

Signed-off-b

block: remove the error_sector argument to blkdev_issue_flush

The argument isn't used by any caller, and drivers don't fill out
bi_sector for flush requests either.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

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ext4: update ext4_sync_file() to not use __generic_file_fsync()

When the filesystem is created without a journal, we eventually call
into __generic_file_fsync() in order to write out all

ext4: update ext4_sync_file() to not use __generic_file_fsync()

When the filesystem is created without a journal, we eventually call
into __generic_file_fsync() in order to write out all the modified
in-core data to the permanent storage device. This function happens to
try and obtain an inode_lock() while synchronizing the files buffer
and it's associated metadata.

Generally, this is fine, however it becomes a problem when there is
higher level code that has already obtained an inode_lock() as this
leads to a recursive lock situation. This case is especially true when
porting across direct I/O to iomap infrastructure as we obtain an
inode_lock() early on in the I/O within ext4_dio_write_iter() and hold
it until the I/O has been completed. Consequently, to not run into
this specific issue, we move away from calling into
__generic_file_fsync() and perform the necessary synchronization tasks
within ext4_sync_file().

Signed-off-by: Matthew Bobrowski <mbobrowski@mbobrowski.org>
Reviewed-by: Ritesh Harjani <riteshh@linux.ibm.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/3495f35ef67f2021b567e28e6f59222e583689b8.1572949325.git.mbobrowski@mbobrowski.org
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

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Revert "ext4: use ext4_write_inode() when fsyncing w/o a journal"

This reverts commit ad211f3e94b314a910d4af03178a0b52a7d1ee0a.

As Jan Kara pointed out, this change was unsafe since

Revert "ext4: use ext4_write_inode() when fsyncing w/o a journal"

This reverts commit ad211f3e94b314a910d4af03178a0b52a7d1ee0a.

As Jan Kara pointed out, this change was unsafe since it means we lose
the call to sync_mapping_buffers() in the nojournal case. The
original point of the commit was avoid taking the inode mutex (since
it causes a lockdep warning in generic/113); but we need the mutex in
order to call sync_mapping_buffers().

The real fix to this problem was discussed here:

https://lore.kernel.org/lkml/20181025150540.259281-4-bvanassche@acm.org

The proposed patch was to fix a syzbot complaint, but the problem can
also demonstrated via "kvm-xfstests -c nojournal generic/113".
Multiple solutions were discused in the e-mail thread, but none have
landed in the kernel as of this writing. Anyway, commit
ad211f3e94b314 is absolutely the wrong way to suppress the lockdep, so
revert it.

Fixes: ad211f3e94b314a910d4af03178a0b52a7d1ee0a ("ext4: use ext4_write_inode() when fsyncing w/o a journal")
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reported: Jan Kara <jack@suse.cz>

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ext4: track writeback errors using the generic tracking infrastructure

We already using mapping_set_error() in fs/ext4/page_io.c, so all we
need to do is to use file_check_and_advance_wb

ext4: track writeback errors using the generic tracking infrastructure

We already using mapping_set_error() in fs/ext4/page_io.c, so all we
need to do is to use file_check_and_advance_wb_err() when handling
fsync() requests in ext4_sync_file().

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org

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ext4: use ext4_write_inode() when fsyncing w/o a journal

In no-journal mode, we previously used __generic_file_fsync() in
no-journal mode. This triggers a lockdep warning, and in additi

ext4: use ext4_write_inode() when fsyncing w/o a journal

In no-journal mode, we previously used __generic_file_fsync() in
no-journal mode. This triggers a lockdep warning, and in addition,
it's not safe to depend on the inode writeback mechanism in the case
ext4. We can solve both problems by calling ext4_write_inode()
directly.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org

show more ...

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

Many source files in the tree are missing licensing information, which
makes it harder for compliance tools

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.

For non */uapi/* files that summary was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139

and resulted in the first patch in this series.

If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930

and resulted in the second patch in this series.

- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:

SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1

and that resulted in the third patch in this series.

- when the two scanners agreed on the detected license(s), that became
the concluded license(s).

- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.

- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).

- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.

- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct

This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

VFS: Convert sb->s_flags & MS_RDONLY to sb_rdonly(sb)

Firstly by applying the following with coccinelle's spatch:

@@ expression SB; @@
-SB->s_flags & MS_RDONLY

VFS: Convert sb->s_flags & MS_RDONLY to sb_rdonly(sb)

Firstly by applying the following with coccinelle's spatch:

@@ expression SB; @@
-SB->s_flags & MS_RDONLY
+sb_rdonly(SB)

to effect the conversion to sb_rdonly(sb), then by applying:

@@ expression A, SB; @@
(
-(!sb_rdonly(SB)) && A
+!sb_rdonly(SB) && A
|
-A != (sb_rdonly(SB))
+A != sb_rdonly(SB)
|
-A == (sb_rdonly(SB))
+A == sb_rdonly(SB)
|
-!(sb_rdonly(SB))
+!sb_rdonly(SB)
|
-A && (sb_rdonly(SB))
+A && sb_rdonly(SB)
|
-A || (sb_rdonly(SB))
+A || sb_rdonly(SB)
|
-(sb_rdonly(SB)) != A
+sb_rdonly(SB) != A
|
-(sb_rdonly(SB)) == A
+sb_rdonly(SB) == A
|
-(sb_rdonly(SB)) && A
+sb_rdonly(SB) && A
|
-(sb_rdonly(SB)) || A
+sb_rdonly(SB) || A
)

@@ expression A, B, SB; @@
(
-(sb_rdonly(SB)) ? 1 : 0
+sb_rdonly(SB)
|
-(sb_rdonly(SB)) ? A : B
+sb_rdonly(SB) ? A : B
)

to remove left over excess bracketage and finally by applying:

@@ expression A, SB; @@
(
-(A & MS_RDONLY) != sb_rdonly(SB)
+(bool)(A & MS_RDONLY) != sb_rdonly(SB)
|
-(A & MS_RDONLY) == sb_rdonly(SB)
+(bool)(A & MS_RDONLY) == sb_rdonly(SB)
)

to make comparisons against the result of sb_rdonly() (which is a bool)
work correctly.

Signed-off-by: David Howells <dhowells@redhat.com>

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ext4: use errseq_t based error handling for reporting data writeback errors

Add a call to filemap_report_wb_err at the end of ext4_sync_file. This
will ensure that we check and advance t

ext4: use errseq_t based error handling for reporting data writeback errors

Add a call to filemap_report_wb_err at the end of ext4_sync_file. This
will ensure that we check and advance the errseq_t in the file, which
allows us to track and report errors on all open fds when they occur.

Signed-off-by: Jeff Layton <jlayton@redhat.com>

show more ...

ext4: add shutdown bit and check for it

Add a shutdown bit that will cause ext4 processing to fail immediately
with EIO.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>

ext4: cleanup ext4_sync_parent()

A condition !hlist_empty(&inode->i_dentry) is always true for open file.
Just remove it. Also ext4_sync_parent() could use some explanation why
races

ext4: cleanup ext4_sync_parent()

A condition !hlist_empty(&inode->i_dentry) is always true for open file.
Just remove it. Also ext4_sync_parent() could use some explanation why
races with rmdir() are not an issue - add a comment explaining that.

Reported-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

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ext4: respect the nobarrier mount option in nojournal mode

Also, if we are going to issue the barrier, we should do this after we
write out the parent directories if necessary.

ext4: respect the nobarrier mount option in nojournal mode

Also, if we are going to issue the barrier, we should do this after we
write out the parent directories if necessary.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>

show more ...

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull fourth vfs update from Al Viro:
"d_inode() annotations from David Howells (sat in for-next since

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull fourth vfs update from Al Viro:
"d_inode() annotations from David Howells (sat in for-next since before
the beginning of merge window) + four assorted fixes"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
RCU pathwalk breakage when running into a symlink overmounting something
fix I_DIO_WAKEUP definition
direct-io: only inc/dec inode->i_dio_count for file systems
fs/9p: fix readdir()
VFS: assorted d_backing_inode() annotations
VFS: fs/inode.c helpers: d_inode() annotations
VFS: fs/cachefiles: d_backing_inode() annotations
VFS: fs library helpers: d_inode() annotations
VFS: assorted weird filesystems: d_inode() annotations
VFS: normal filesystems (and lustre): d_inode() annotations
VFS: security/: d_inode() annotations
VFS: security/: d_backing_inode() annotations
VFS: net/: d_inode() annotations
VFS: net/unix: d_backing_inode() annotations
VFS: kernel/: d_inode() annotations
VFS: audit: d_backing_inode() annotations
VFS: Fix up some ->d_inode accesses in the chelsio driver
VFS: Cachefiles should perform fs modifications on the top layer only
VFS: AF_UNIX sockets should call mknod on the top layer only

show more ...

VFS: normal filesystems (and lustre): d_inode() annotations

that's the bulk of filesystem drivers dealing with inodes of their own

Signed-off-by: David Howells <dhowells@redhat.com>

VFS: normal filesystems (and lustre): d_inode() annotations

that's the bulk of filesystem drivers dealing with inodes of their own

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

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ext4: remove unused header files

Remove unused header files and header files which are included in
ext4.h.

Signed-off-by: Sheng Yong <shengyong1@huawei.com>
Signed-off-by: T

ext4: remove unused header files

Remove unused header files and header files which are included in
ext4.h.

Signed-off-by: Sheng Yong <shengyong1@huawei.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

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ext4: Fix fsync error handling after filesystem abort

If filesystem was aborted after inode's write back is complete
but before its metadata was updated we may return success
results

ext4: Fix fsync error handling after filesystem abort

If filesystem was aborted after inode's write back is complete
but before its metadata was updated we may return success
results in data loss.
In order to handle fs abort correctly we have to check
fs state once we discover that it is in MS_RDONLY state

Test case: http://patchwork.ozlabs.org/patch/244297

Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

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ext4: remove i_mutex from ext4_file_sync()

After removal of ext4_flush_unwritten_io() call, ext4_file_sync()
doesn't need i_mutex anymore. Forcing of transaction commits doesn't
need

ext4: remove i_mutex from ext4_file_sync()

After removal of ext4_flush_unwritten_io() call, ext4_file_sync()
doesn't need i_mutex anymore. Forcing of transaction commits doesn't
need i_mutex as there's nothing inode specific in that code apart from
grabbing transaction ids from the inode. So remove the lock.

Reviewed-by: Zheng Liu <wenqing.lz@taobao.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

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ext4: use generic_file_fsync() in ext4_file_fsync() in nojournal mode

Just use the generic function instead of duplicating it. We only need
to reshuffle the read-only check a bit (which

ext4: use generic_file_fsync() in ext4_file_fsync() in nojournal mode

Just use the generic function instead of duplicating it. We only need
to reshuffle the read-only check a bit (which is there to prevent
writing to a filesystem which has been remounted read-only after error
I assume).

Reviewed-by: Zheng Liu <wenqing.lz@taobao.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

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ext4: defer clearing of PageWriteback after extent conversion

Currently PageWriteback bit gets cleared from put_io_page() called
from ext4_end_bio(). This is somewhat inconvenient as ex

ext4: defer clearing of PageWriteback after extent conversion

Currently PageWriteback bit gets cleared from put_io_page() called
from ext4_end_bio(). This is somewhat inconvenient as extent tree is
not fully updated at that time (unwritten extents are not marked as
written) so we cannot read the data back yet. This design was
dictated by lock ordering as we cannot start a transaction while
PageWriteback bit is set (we could easily deadlock with
ext4_da_writepages()). But now that we use transaction reservation
for extent conversion, locking issues are solved and we can move
PageWriteback bit clearing after extent conversion is done. As a
result we can remove wait for unwritten extent conversion from
ext4_sync_file() because it already implicitely happens through
wait_on_page_writeback().

We implement deferring of PageWriteback clearing by queueing completed
bios to appropriate io_end and processing all the pages when io_end is
going to be freed instead of at the moment ext4_io_end() is called.

Reviewed-by: Zheng Liu <wenqing.lz@taobao.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

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ext4/jbd2: don't wait (forever) for stale tid caused by wraparound

In the case where an inode has a very stale transaction id (tid) in
i_datasync_tid or i_sync_tid, it's possible that af

ext4/jbd2: don't wait (forever) for stale tid caused by wraparound

In the case where an inode has a very stale transaction id (tid) in
i_datasync_tid or i_sync_tid, it's possible that after a very large
(2**31) number of transactions, that the tid number space might wrap,
causing tid_geq()'s calculations to fail.

Commit deeeaf13 "jbd2: fix fsync() tid wraparound bug", later modified
by commit e7b04ac0 "jbd2: don't wake kjournald unnecessarily",
attempted to fix this problem, but it only avoided kjournald spinning
forever by fixing the logic in jbd2_log_start_commit().

Unfortunately, in the codepaths in fs/ext4/fsync.c and fs/ext4/inode.c
that might call jbd2_log_start_commit() with a stale tid, those
functions will subsequently call jbd2_log_wait_commit() with the same
stale tid, and then wait for a very long time. To fix this, we
replace the calls to jbd2_log_start_commit() and
jbd2_log_wait_commit() with a call to a new function,
jbd2_complete_transaction(), which will correctly handle stale tid's.

As a bonus, jbd2_complete_transaction() will avoid locking
j_state_lock for writing unless a commit needs to be started. This
should have a small (but probably not measurable) improvement for
ext4's scalability.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Reported-by: Ben Hutchings <ben@decadent.org.uk>
Reported-by: George Barnett <gbarnett@atlassian.com>
Cc: stable@vger.kernel.org

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ext4: fix an incorrect comment about i_mutex

i_mutex is not held when ->sync_file is called.

Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Andy Lutomirski <luto@amacapital

ext4: fix an incorrect comment about i_mutex

i_mutex is not held when ->sync_file is called.

Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

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ext4: use sync_inode_metadata() when syncing inode metadata

We have a dedicated interface to sync inode metadata. Use it to
simplify ext4's code some.

Signed-off-by: Guo Chao <

ext4: use sync_inode_metadata() when syncing inode metadata

We have a dedicated interface to sync inode metadata. Use it to
simplify ext4's code some.

Signed-off-by: Guo Chao <yan@linux.vnet.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Reviewed-by: Lukas Czerner <lczerner@redhat.com>

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ext4: fix ext4_flush_completed_IO wait semantics

BUG #1) All places where we call ext4_flush_completed_IO are broken
because buffered io and DIO/AIO goes through three stages

ext4: fix ext4_flush_completed_IO wait semantics

BUG #1) All places where we call ext4_flush_completed_IO are broken
because buffered io and DIO/AIO goes through three stages
1) submitted io,
2) completed io (in i_completed_io_list) conversion pended
3) finished io (conversion done)
And by calling ext4_flush_completed_IO we will flush only
requests which were in (2) stage, which is wrong because:
1) punch_hole and truncate _must_ wait for all outstanding unwritten io
regardless to it's state.
2) fsync and nolock_dio_read should also wait because there is
a time window between end_page_writeback() and ext4_add_complete_io()
As result integrity fsync is broken in case of buffered write
to fallocated region:
fsync blkdev_completion
->filemap_write_and_wait_range
->ext4_end_bio
->end_page_writeback
<-- filemap_write_and_wait_range return
->ext4_flush_completed_IO
sees empty i_completed_io_list but pended
conversion still exist
->ext4_add_complete_io

BUG #2) Race window becomes wider due to the 'ext4: completed_io
locking cleanup V4' patch series

This patch make following changes:
1) ext4_flush_completed_io() now first try to flush completed io and when
wait for any outstanding unwritten io via ext4_unwritten_wait()
2) Rename function to more appropriate name.
3) Assert that all callers of ext4_flush_unwritten_io should hold i_mutex to
prevent endless wait

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>

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