linux-stable.git/fs/ext4/super.c, branch linux-5.7.y

ext4: avoid race conditions when remounting with options that change dax

2020-06-24T15:49:20+00:00

[ Upstream commit 829b37b8cddb1db75c1b7905505b90e593b15db1 ]

Trying to change dax mount options when remounting could allow mount
options to be enabled for a small amount of time, and then the mount
option change would be reverted.

In the case of "mount -o remount,dax", this can cause a race where
files would temporarily treated as DAX --- and then not.

Cc: stable@kernel.org
Reported-by: syzbot+bca9799bf129256190da@syzkaller.appspotmail.com
Signed-off-by: Theodore Ts'o 
Signed-off-by: Sasha Levin

ext4, jbd2: ensure panic by fix a race between jbd2 abort and ext4 error handlers

2020-06-24T15:49:17+00:00

commit 7b97d868b7ab2448859668de9222b8af43f76e78 upstream.

In the ext4 filesystem with errors=panic, if one process is recording
errno in the superblock when invoking jbd2_journal_abort() due to some
error cases, it could be raced by another __ext4_abort() which is
setting the SB_RDONLY flag but missing panic because errno has not been
recorded.

jbd2_journal_commit_transaction()
 jbd2_journal_abort()
  journal->j_flags |= JBD2_ABORT;
  jbd2_journal_update_sb_errno()
                                    | ext4_journal_check_start()
                                    |  __ext4_abort()
                                    |   sb->s_flags |= SB_RDONLY;
                                    |   if (!JBD2_REC_ERR)
                                    |        return;
  journal->j_flags |= JBD2_REC_ERR;

Finally, it will no longer trigger panic because the filesystem has
already been set read-only. Fix this by introduce j_abort_mutex to make
sure journal abort is completed before panic, and remove JBD2_REC_ERR
flag.

Fixes: 4327ba52afd03 ("ext4, jbd2: ensure entering into panic after recording an error in superblock")
Signed-off-by: zhangyi (F) 
Reviewed-by: Jan Kara 
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20200609073540.3810702-1-yi.zhang@huawei.com
Signed-off-by: Theodore Ts'o 
Signed-off-by: Greg Kroah-Hartman

ext4: stop overwrite the errcode in ext4_setup_super

2020-06-24T15:49:13+00:00

[ Upstream commit 5adaccac46ea79008d7b75f47913f1a00f91d0ce ]

Now the errcode from ext4_commit_super will overwrite EROFS exists in
ext4_setup_super. Actually, no need to call ext4_commit_super since we
will return EROFS. Fix it by goto done directly.

Fixes: c89128a00838 ("ext4: handle errors on ext4_commit_super")
Signed-off-by: yangerkun 
Reviewed-by: Jan Kara 
Link: https://lore.kernel.org/r/20200601073404.3712492-1-yangerkun@huawei.com
Signed-off-by: Theodore Ts'o 
Signed-off-by: Sasha Levin

ext4: handle ext4_mark_inode_dirty errors

2020-06-24T15:49:03+00:00

[ Upstream commit 4209ae12b12265d475bba28634184423149bd14f ]

ext4_mark_inode_dirty() can fail for real reasons. Ignoring its return
value may lead ext4 to ignore real failures that would result in
corruption / crashes. Harden ext4_mark_inode_dirty error paths to fail
as soon as possible and return errors to the caller whenever
appropriate.

One of the possible scnearios when this bug could affected is that
while creating a new inode, its directory entry gets added
successfully but while writing the inode itself mark_inode_dirty
returns error which is ignored. This would result in inconsistency
that the directory entry points to a non-existent inode.

Ran gce-xfstests smoke tests and verified that there were no
regressions.

Signed-off-by: Harshad Shirwadkar 
Link: https://lore.kernel.org/r/20200427013438.219117-1-harshadshirwadkar@gmail.com
Signed-off-by: Theodore Ts'o 
Signed-off-by: Sasha Levin

ext4: remove set but not used variable 'es'

2020-04-16T03:58:49+00:00

Fix the following gcc warning:

fs/ext4/super.c:599:27: warning: variable 'es' set but not used [-Wunused-but-set-variable]
  struct ext4_super_block *es;
                           ^~
Fixes: 2ea2fc775321 ("ext4: save all error info in save_error_info() and drop ext4_set_errno()")
Reported-by: Hulk Robot 
Signed-off-by: Jason Yan 
Link: https://lore.kernel.org/r/20200402033939.25303-1-yanaijie@huawei.com
Signed-off-by: Theodore Ts'o

ext4: use non-movable memory for superblock readahead

2020-04-16T03:58:48+00:00

Since commit a8ac900b8163 ("ext4: use non-movable memory for the
superblock") buffers for ext4 superblock were allocated using
the sb_bread_unmovable() helper which allocated buffer heads
out of non-movable memory blocks. It was necessarily to not block
page migrations and do not cause cma allocation failures.

However commit 85c8f176a611 ("ext4: preload block group descriptors")
broke this by introducing pre-reading of the ext4 superblock.
The problem is that __breadahead() is using __getblk() underneath,
which allocates buffer heads out of movable memory.

It resulted in page migration failures I've seen on a machine
with an ext4 partition and a preallocated cma area.

Fix this by introducing sb_breadahead_unmovable() and
__breadahead_gfp() helpers which use non-movable memory for buffer
head allocations and use them for the ext4 superblock readahead.

Reviewed-by: Andreas Dilger 
Fixes: 85c8f176a611 ("ext4: preload block group descriptors")
Signed-off-by: Roman Gushchin 
Link: https://lore.kernel.org/r/20200229001411.128010-1-guro@fb.com
Signed-off-by: Theodore Ts'o

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

2020-04-05T17:54:03+00:00

Pull ext4 updates from Ted Ts'o:

 - Replace ext4's bmap and iopoll implementations to use iomap.

 - Clean up extent tree handling.

 - Other cleanups and miscellaneous bug fixes

* tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (31 commits)
  ext4: save all error info in save_error_info() and drop ext4_set_errno()
  ext4: fix incorrect group count in ext4_fill_super error message
  ext4: fix incorrect inodes per group in error message
  ext4: don't set dioread_nolock by default for blocksize < pagesize
  ext4: disable dioread_nolock whenever delayed allocation is disabled
  ext4: do not commit super on read-only bdev
  ext4: avoid ENOSPC when avoiding to reuse recently deleted inodes
  ext4: unregister sysfs path before destroying jbd2 journal
  ext4: check for non-zero journal inum in ext4_calculate_overhead
  ext4: remove map_from_cluster from ext4_ext_map_blocks
  ext4: clean up ext4_ext_insert_extent() call in ext4_ext_map_blocks()
  ext4: mark block bitmap corrupted when found instead of BUGON
  ext4: use flexible-array member for xattr structs
  ext4: use flexible-array member in struct fname
  Documentation: correct the description of FIEMAP_EXTENT_LAST
  ext4: move ext4_fiemap to use iomap framework
  ext4: make ext4_ind_map_blocks work with fiemap
  ext4: move ext4 bmap to use iomap infrastructure
  ext4: optimize ext4_ext_precache for 0 depth
  ext4: add IOMAP_F_MERGED for non-extent based mapping
  ...

ext4: save all error info in save_error_info() and drop ext4_set_errno()

2020-04-01T21:29:06+00:00

Using a separate function, ext4_set_errno() to set the errno is
problematic because it doesn't do the right thing once
s_last_error_errorcode is non-zero.  It's also less racy to set all of
the error information all at once.  (Also, as a bonus, it shrinks code
size slightly.)

Link: https://lore.kernel.org/r/20200329020404.686965-1-tytso@mit.edu
Fixes: 878520ac45f9 ("ext4: save the error code which triggered...")
Signed-off-by: Theodore Ts'o

ext4: fix incorrect group count in ext4_fill_super error message

2020-03-29T03:11:39+00:00

ext4_fill_super doublechecks the number of groups before mounting; if
that check fails, the resulting error message prints the group count
from the ext4_sb_info sbi, which hasn't been set yet. Print the freshly
computed group count instead (which at that point has just been computed
in "blocks_count").

Signed-off-by: Josh Triplett 
Fixes: 4ec1102813798 ("ext4: Add sanity checks for the superblock before mounting the filesystem")
Link: https://lore.kernel.org/r/8b957cd1513fcc4550fe675c10bcce2175c33a49.1585431964.git.josh@joshtriplett.org
Signed-off-by: Theodore Ts'o

ext4: fix incorrect inodes per group in error message

2020-03-29T03:11:12+00:00

If ext4_fill_super detects an invalid number of inodes per group, the
resulting error message printed the number of blocks per group, rather
than the number of inodes per group. Fix it to print the correct value.

Fixes: cd6bb35bf7f6d ("ext4: use more strict checks for inodes_per_block on mount")
Link: https://lore.kernel.org/r/8be03355983a08e5d4eed480944613454d7e2550.1585434649.git.josh@joshtriplett.org
Reviewed-by: Andreas Dilger 
Signed-off-by: Josh Triplett 
Signed-off-by: Theodore Ts'o