linux-stable.git/fs/ext4, branch v6.4

ext4: drop the call to ext4_error() from ext4_get_group_info()

2023-06-15T02:24:05+00:00

A recent patch added a call to ext4_error() which is problematic since
some callers of the ext4_get_group_info() function may be holding a
spinlock, whereas ext4_error() must never be called in atomic context.

This triggered a report from Syzbot: "BUG: sleeping function called from
invalid context in ext4_update_super" (see the link below).

Therefore, drop the call to ext4_error() from ext4_get_group_info(). In
the meantime use eight characters tabs instead of nine characters ones.

Reported-by: syzbot+4acc7d910e617b360859@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/00000000000070575805fdc6cdb2@google.com/
Fixes: 5354b2af3406 ("ext4: allow ext4_get_group_info() to fail")
Suggested-by: Theodore Ts'o 
Signed-off-by: Fabio M. De Francesco 
Link: https://lore.kernel.org/r/20230614100446.14337-1-fmdefrancesco@gmail.com

Revert "ext4: remove unnecessary check in ext4_bg_num_gdb_nometa"

2023-06-15T02:22:27+00:00

This reverts commit ad3f09be6cfe332be8ff46c78e6ec0f8839107aa.

The reverted commit was intended to simpfy the code to get group
descriptor block number in non-meta block group by assuming
s_gdb_count is block number used for all non-meta block group descriptors.
However s_gdb_count is block number used for all meta *and* non-meta
group descriptors. So s_gdb_group will be > actual group descriptor block
number used for all non-meta block group which should be "total non-meta
block group" / "group descriptors per block", e.g. s_first_meta_bg.

Signed-off-by: Kemeng Shi 
Link: https://lore.kernel.org/r/20230613225025.3859522-1-shikemeng@huaweicloud.com
Fixes: ad3f09be6cfe ("ext4: remove unnecessary check in ext4_bg_num_gdb_nometa")
Cc: stable@kernel.org
Signed-off-by: Theodore Ts'o

ext4: only check dquot_initialize_needed() when debugging

2023-06-08T14:06:40+00:00

ext4_xattr_block_set() relies on its caller to call dquot_initialize()
on the inode.  To assure that this has happened there are WARN_ON
checks.  Unfortunately, this is subject to false positives if there is
an antagonist thread which is flipping the file system at high rates
between r/o and rw.  So only do the check if EXT4_XATTR_DEBUG is
enabled.

Link: https://lore.kernel.org/r/20230608044056.GA1418535@mit.edu
Signed-off-by: Theodore Ts'o

Revert "ext4: don't clear SB_RDONLY when remounting r/w until quota is re-enabled"

2023-06-08T13:57:04+00:00

This reverts commit a44be64bbecb15a452496f60db6eacfee2b59c79.

Link: https://lore.kernel.org/r/653b3359-2005-21b1-039d-c55ca4cffdcc@gmail.com
Signed-off-by: Theodore Ts'o

Revert "ext4: remove ac->ac_found > sbi->s_mb_min_to_scan dead check in ext4_mb_check_limits"

2023-06-02T18:47:29+00:00

This reverts commit 32c0869370194ae5ac9f9f501953ef693040f6a1.

The reverted commit was intended to remove a dead check however it was observed
that this check was actually being used to exit early instead of looping
sbi->s_mb_max_to_scan times when we are able to find a free extent bigger than
the goal extent. Due to this, a my performance tests (fsmark, parallel file
writes in a highly fragmented FS) were seeing a 2x-3x regression.

Example, the default value of the following variables is:

sbi->s_mb_max_to_scan = 200
sbi->s_mb_min_to_scan = 10

In ext4_mb_check_limits() if we find an extent smaller than goal, then we return
early and try again. This loop will go on until we have processed
sbi->s_mb_max_to_scan(=200) number of free extents at which point we exit and
just use whatever we have even if it is smaller than goal extent.

Now, the regression comes when we find an extent bigger than goal. Earlier, in
this case we would loop only sbi->s_mb_min_to_scan(=10) times and then just use
the bigger extent. However with commit 32c08693 that check was removed and hence
we would loop sbi->s_mb_max_to_scan(=200) times even though we have a big enough
free extent to satisfy the request. The only time we would exit early would be
when the free extent is *exactly* the size of our goal, which is pretty uncommon
occurrence and so we would almost always end up looping 200 times.

Hence, revert the commit by adding the check back to fix the regression. Also
add a comment to outline this policy.

Fixes: 32c086937019 ("ext4: remove ac->ac_found > sbi->s_mb_min_to_scan dead check in ext4_mb_check_limits")
Signed-off-by: Ojaswin Mujoo 
Reviewed-by: Ritesh Harjani (IBM) 
Reviewed-by: Kemeng Shi 
Link: https://lore.kernel.org/r/ddcae9658e46880dfec2fb0aa61d01fb3353d202.1685449706.git.ojaswin@linux.ibm.com
Signed-off-by: Theodore Ts'o

ext4: enable the lazy init thread when remounting read/write

2023-05-30T19:33:57+00:00

In commit a44be64bbecb ("ext4: don't clear SB_RDONLY when remounting
r/w until quota is re-enabled") we defer clearing tyhe SB_RDONLY flag
in struct super.  However, we didn't defer when we checked sb_rdonly()
to determine the lazy itable init thread should be enabled, with the
next result that the lazy inode table initialization would not be
properly started.  This can cause generic/231 to fail in ext4's
nojournal mode.

Fix this by moving when we decide to start or stop the lazy itable
init thread to after we clear the SB_RDONLY flag when we are
remounting the file system read/write.

Fixes a44be64bbecb ("ext4: don't clear SB_RDONLY when remounting r/w until...")

Signed-off-by: Theodore Ts'o 
Link: https://lore.kernel.org/r/20230527035729.1001605-1-tytso@mit.edu
Signed-off-by: Theodore Ts'o

ext4: fix fsync for non-directories

2023-05-30T19:33:57+00:00

Commit e360c6ed7274 ("ext4: Drop special handling of journalled data
from ext4_sync_file()") simplified ext4_sync_file() by dropping special
handling of journalled data mode as it was not needed anymore. However
that branch was also used for directories and symlinks and since the
fastcommit code does not track metadata changes to non-regular files, the
change has caused e.g. fsync(2) on directories to not commit transaction
as it should. Fix the problem by adding handling for non-regular files.

Fixes: e360c6ed7274 ("ext4: Drop special handling of journalled data from ext4_sync_file()")
Reported-by: Eric Whitney 
Link: https://lore.kernel.org/all/ZFqO3xVnmhL7zv1x@debian-BULLSEYE-live-builder-AMD64
Signed-off-by: Jan Kara 
Tested-by: Eric Whitney 
Link: https://lore.kernel.org/r/20230524104453.8734-1-jack@suse.cz
Signed-off-by: Theodore Ts'o

ext4: add lockdep annotations for i_data_sem for ea_inode's

2023-05-30T19:33:57+00:00

Treat i_data_sem for ea_inodes as being in their own lockdep class to
avoid lockdep complaints about ext4_setattr's use of inode_lock() on
normal inodes potentially causing lock ordering with i_data_sem on
ea_inodes in ext4_xattr_inode_write().  However, ea_inodes will be
operated on by ext4_setattr(), so this isn't a problem.

Cc: stable@kernel.org
Link: https://syzkaller.appspot.com/bug?extid=298c5d8fb4a128bc27b0
Reported-by: syzbot+298c5d8fb4a128bc27b0@syzkaller.appspotmail.com
Signed-off-by: Theodore Ts'o 
Link: https://lore.kernel.org/r/20230524034951.779531-5-tytso@mit.edu
Signed-off-by: Theodore Ts'o

ext4: disallow ea_inodes with extended attributes

2023-05-30T19:33:57+00:00

An ea_inode stores the value of an extended attribute; it can not have
extended attributes itself, or this will cause recursive nightmares.
Add a check in ext4_iget() to make sure this is the case.

Cc: stable@kernel.org
Reported-by: syzbot+e44749b6ba4d0434cd47@syzkaller.appspotmail.com
Signed-off-by: Theodore Ts'o 
Link: https://lore.kernel.org/r/20230524034951.779531-4-tytso@mit.edu
Signed-off-by: Theodore Ts'o

ext4: set lockdep subclass for the ea_inode in ext4_xattr_inode_cache_find()

2023-05-30T19:33:50+00:00

If the ea_inode has been pushed out of the inode cache while there is
still a reference in the mb_cache, the lockdep subclass will not be
set on the inode, which can lead to some lockdep false positives.

Fixes: 33d201e0277b ("ext4: fix lockdep warning about recursive inode locking")
Cc: stable@kernel.org
Reported-by: syzbot+d4b971e744b1f5439336@syzkaller.appspotmail.com
Signed-off-by: Theodore Ts'o 
Link: https://lore.kernel.org/r/20230524034951.779531-3-tytso@mit.edu
Signed-off-by: Theodore Ts'o