commit 073931017b upstream.
When file permissions are modified via chmod(2) and the user is not in
the owning group or capable of CAP_FSETID, the setgid bit is cleared in
inode_change_ok(). Setting a POSIX ACL via setxattr(2) sets the file
permissions as well as the new ACL, but doesn't clear the setgid bit in
a similar way; this allows to bypass the check in chmod(2). Fix that.
References: CVE-2016-7097
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
[bwh: Backported to 3.16:
- Drop changes to orangefs
- Adjust context
- Update ext3 as well]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit 31051c85b5 upstream.
inode_change_ok() will be resposible for clearing capabilities and IMA
extended attributes and as such will need dentry. Give it as an argument
to inode_change_ok() instead of an inode. Also rename inode_change_ok()
to setattr_prepare() to better relect that it does also some
modifications in addition to checks.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
[bwh: Backported to 3.16:
- Drop changes to orangefs, overlayfs
- Adjust filenames, context
- In fuse, pass dentry to fuse_do_setattr()
- In nfsd, pass dentry to nfsd_sanitize_attrs()
- In xfs, pass dentry to xfs_setattr_nonsize() and xfs_setattr_size()
- Update ext3 as well]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit 829fa70ddd upstream.
A number of fuzzing failures seem to be caused by allocation bitmaps
or other metadata blocks being pointed at the superblock.
This can cause kernel BUG or WARNings once the superblock is
overwritten, so validate the group descriptor blocks to make sure this
doesn't happen.
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit c65d5c6c81 upstream.
If we encounter a filesystem error during orphan cleanup, we should stop.
Otherwise, we may end up in an infinite loop where the same inode is
processed again and again.
EXT4-fs (loop0): warning: checktime reached, running e2fsck is recommended
EXT4-fs error (device loop0): ext4_mb_generate_buddy:758: group 2, block bitmap and bg descriptor inconsistent: 6117 vs 0 free clusters
Aborting journal on device loop0-8.
EXT4-fs (loop0): Remounting filesystem read-only
EXT4-fs error (device loop0) in ext4_free_blocks:4895: Journal has aborted
EXT4-fs error (device loop0) in ext4_do_update_inode:4893: Journal has aborted
EXT4-fs error (device loop0) in ext4_do_update_inode:4893: Journal has aborted
EXT4-fs error (device loop0) in ext4_ext_remove_space:3068: IO failure
EXT4-fs error (device loop0) in ext4_ext_truncate:4667: Journal has aborted
EXT4-fs error (device loop0) in ext4_orphan_del:2927: Journal has aborted
EXT4-fs error (device loop0) in ext4_do_update_inode:4893: Journal has aborted
EXT4-fs (loop0): Inode 16 (00000000618192a0): orphan list check failed!
[...]
EXT4-fs (loop0): Inode 16 (0000000061819748): orphan list check failed!
[...]
EXT4-fs (loop0): Inode 16 (0000000061819bf0): orphan list check failed!
[...]
See-also: c9eb13a910 ("ext4: fix hang when processing corrupted orphaned inode list")
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit 554a5ccc4e upstream.
If we hit this error when mounted with errors=continue or
errors=remount-ro:
EXT4-fs error (device loop0): ext4_mb_mark_diskspace_used:2940: comm ext4.exe: Allocating blocks 5090-6081 which overlap fs metadata
then ext4_mb_new_blocks() will call ext4_mb_release_context() and try to
continue. However, ext4_mb_release_context() is the wrong thing to call
here since we are still actually using the allocation context.
Instead, just error out. We could retry the allocation, but there is a
possibility of getting stuck in an infinite loop instead, so this seems
safer.
[ Fixed up so we don't return EAGAIN to userspace. --tytso ]
Fixes: 8556e8f3b6 ("ext4: Don't allow new groups to be added during block allocation")
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
[bwh: Backported to 3.16: use EIO instead of EFSCORRUPTED]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit 5b9554dc5b upstream.
If s_reserved_gdt_blocks is extremely large, it's possible for
ext4_init_block_bitmap(), which is called when ext4 sets up an
uninitialized block bitmap, to corrupt random kernel memory. Add the
same checks which e2fsck has --- it must never be larger than
blocksize / sizeof(__u32) --- and then add a backup check in
ext4_init_block_bitmap() in case the superblock gets modified after
the file system is mounted.
Reported-by: Vegard Nossum <vegard.nossum@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
[bwh: Backported to 3.16:
- Use EIO instead of EFSCORRUPTED
- Adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit 6a7fd522a7 upstream.
If ext4_fill_super() fails early, it's possible for ext4_evict_inode()
to call ext4_should_journal_data() before superblock options and flags
are fully set up. In that case, the iput() on the journal inode can
end up causing a BUG().
Work around this problem by reordering the tests so we only call
ext4_should_journal_data() after we know it's not the journal inode.
Fixes: 2d859db3e4 ("ext4: fix data corruption in inodes with journalled data")
Fixes: 2b405bfa84 ("ext4: fix data=journal fast mount/umount hang")
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit 646caa9c8e upstream.
Commit 06bd3c36a7 (ext4: fix data exposure after a crash) uncovered a
deadlock in ext4_writepages() which was previously much harder to hit.
After this commit xfstest generic/130 reproduces the deadlock on small
filesystems.
The problem happens when ext4_do_update_inode() sets LARGE_FILE feature
and marks current inode handle as synchronous. That subsequently results
in ext4_journal_stop() called from ext4_writepages() to block waiting for
transaction commit while still holding page locks, reference to io_end,
and some prepared bio in mpd structure each of which can possibly block
transaction commit from completing and thus results in deadlock.
Fix the problem by releasing page locks, io_end reference, and
submitting prepared bio before calling ext4_journal_stop().
[ Changed to defer the call to ext4_journal_stop() only if the handle
is synchronous. --tytso ]
Reported-and-tested-by: Eryu Guan <eguan@redhat.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit f70749ca42 upstream.
An extent with lblock = 4294967295 and len = 1 will pass the
ext4_valid_extent() test:
ext4_lblk_t last = lblock + len - 1;
if (len == 0 || lblock > last)
return 0;
since last = 4294967295 + 1 - 1 = 4294967295. This would later trigger
the BUG_ON(es->es_lblk + es->es_len < es->es_lblk) in ext4_es_end().
We can simplify it by removing the - 1 altogether and changing the test
to use lblock + len <= lblock, since now if len = 0, then lblock + 0 ==
lblock and it fails, and if len > 0 then lblock + len > lblock in order
to pass (i.e. it doesn't overflow).
Fixes: 5946d0893 ("ext4: check for overlapping extents in ext4_valid_extent_entries()")
Fixes: 2f974865f ("ext4: check for zero length extent explicitly")
Cc: Eryu Guan <guaneryu@gmail.com>
Signed-off-by: Phil Turnbull <phil.turnbull@oracle.com>
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit 7827a7f6eb upstream.
Instead of just printing warning messages, if the orphan list is
corrupted, declare the file system is corrupted. If there are any
reserved inodes in the orphaned inode list, declare the file system
corrupted and stop right away to avoid doing more potential damage to
the file system.
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
[bwh: Backported to 3.16: leave error code as EIO]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit c9eb13a910 upstream.
If the orphaned inode list contains inode #5, ext4_iget() returns a
bad inode (since the bootloader inode should never be referenced
directly). Because of the bad inode, we end up processing the inode
repeatedly and this hangs the machine.
This can be reproduced via:
mke2fs -t ext4 /tmp/foo.img 100
debugfs -w -R "ssv last_orphan 5" /tmp/foo.img
mount -o loop /tmp/foo.img /mnt
(But don't do this if you are using an unpatched kernel if you care
about the system staying functional. :-)
This bug was found by the port of American Fuzzy Lop into the kernel
to find file system problems[1]. (Since it *only* happens if inode #5
shows up on the orphan list --- 3, 7, 8, etc. won't do it, it's not
surprising that AFL needed two hours before it found it.)
[1] http://events.linuxfoundation.org/sites/events/files/slides/AFL%20filesystem%20fuzzing%2C%20Vault%202016_0.pdf
Reported by: Vegard Nossum <vegard.nossum@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit 06bd3c36a7 upstream.
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().
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>
[bwh: Backported to 3.16:
- Drop check for EXT4_GET_BLOCKS_ZERO flag
- Adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit 5e1021f2b6 upstream.
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>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit daf647d2dd upstream.
With the internal Quota feature, mke2fs creates empty quota inodes and
quota usage tracking is enabled as soon as the file system is mounted.
Since quotacheck is no longer preallocating all of the blocks in the
quota inode that are likely needed to be written to, we are now seeing
a lockdep false positive caused by needing to allocate a quota block
from inside ext4_map_blocks(), while holding i_data_sem for a data
inode. This results in this complaint:
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&ei->i_data_sem);
lock(&s->s_dquot.dqio_mutex);
lock(&ei->i_data_sem);
lock(&s->s_dquot.dqio_mutex);
Google-Bug-Id: 27907753
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
commit 6ffe77bad5 upstream.
In commit bcff24887d ("ext4: don't read blocks from disk after extents
being swapped") bh is not updated correctly in the for loop and wrong
data has been written to disk. generic/324 catches this on sub-page
block size ext4.
Fixes: bcff24887d ("ext4: don't read blocks from disk after extentsbeing swapped")
Signed-off-by: Eryu Guan <guaneryu@gmail.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit 74dae42785 upstream.
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.
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit ed8ad83808 upstream.
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.
Reported-by: Nikolay Borisov <kernel@kyup.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
[ luis: backported to 3.16:
- replaced READ_ONCE() by ACCESS_ONCE() ]
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit bcff24887d upstream.
I notice ext4/307 fails occasionally on ppc64 host, reporting md5
checksum mismatch after moving data from original file to donor file.
The reason is that move_extent_per_page() calls __block_write_begin()
and block_commit_write() to write saved data from original inode blocks
to donor inode blocks, but __block_write_begin() not only maps buffer
heads but also reads block content from disk if the size is not block
size aligned. At this time the physical block number in mapped buffer
head is pointing to the donor file not the original file, and that
results in reading wrong data to page, which get written to disk in
following block_commit_write call.
This also can be reproduced by the following script on 1k block size ext4
on x86_64 host:
mnt=/mnt/ext4
donorfile=$mnt/donor
testfile=$mnt/testfile
e4compact=~/xfstests/src/e4compact
rm -f $donorfile $testfile
# reserve space for donor file, written by 0xaa and sync to disk to
# avoid EBUSY on EXT4_IOC_MOVE_EXT
xfs_io -fc "pwrite -S 0xaa 0 1m" -c "fsync" $donorfile
# create test file written by 0xbb
xfs_io -fc "pwrite -S 0xbb 0 1023" -c "fsync" $testfile
# compute initial md5sum
md5sum $testfile | tee md5sum.txt
# drop cache, force e4compact to read data from disk
echo 3 > /proc/sys/vm/drop_caches
# test defrag
echo "$testfile" | $e4compact -i -v -f $donorfile
# check md5sum
md5sum -c md5sum.txt
Fix it by creating & mapping buffer heads only but not reading blocks
from disk, because all the data in page is guaranteed to be up-to-date
in mext_page_mkuptodate().
Signed-off-by: Eryu Guan <guaneryu@gmail.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
[ luis: backported to 3.16: adjusted context ]
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit a4dad1ae24 upstream.
In ext4, the bottom two bits of {a,c,m}time_extra are used to extend
the {a,c,m}time fields, deferring the year 2038 problem to the year
2446.
When decoding these extended fields, for times whose bottom 32 bits
would represent a negative number, sign extension causes the 64-bit
extended timestamp to be negative as well, which is not what's
intended. This patch corrects that issue, so that the only negative
{a,c,m}times are those between 1901 and 1970 (as per 32-bit signed
timestamps).
Some older kernels might have written pre-1970 dates with 1,1 in the
extra bits. This patch treats those incorrectly-encoded dates as
pre-1970, instead of post-2311, until kernel 4.20 is released.
Hopefully by then e2fsck will have fixed up the bad data.
Also add a comment explaining the encoding of ext4's extra {a,c,m}time
bits.
Signed-off-by: David Turner <novalis@novalis.org>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reported-by: Mark Harris <mh8928@yahoo.com>
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=23732
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit 4327ba52af upstream.
If a EXT4 filesystem utilizes JBD2 journaling and an error occurs, the
journaling will be aborted first and the error number will be recorded
into JBD2 superblock and, finally, the system will enter into the
panic state in "errors=panic" option. But, in the rare case, this
sequence is little twisted like the below figure and it will happen
that the system enters into panic state, which means the system reset
in mobile environment, before completion of recording an error in the
journal superblock. In this case, e2fsck cannot recognize that the
filesystem failure occurred in the previous run and the corruption
wouldn't be fixed.
Task A Task B
ext4_handle_error()
-> jbd2_journal_abort()
-> __journal_abort_soft()
-> __jbd2_journal_abort_hard()
| -> journal->j_flags |= JBD2_ABORT;
|
| __ext4_abort()
| -> jbd2_journal_abort()
| | -> __journal_abort_soft()
| | -> if (journal->j_flags & JBD2_ABORT)
| | return;
| -> panic()
|
-> jbd2_journal_update_sb_errno()
Tested-by: Hobin Woo <hobin.woo@samsung.com>
Signed-off-by: Daeho Jeong <daeho.jeong@samsung.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit 904dad4742 upstream.
"group" is the group where the backup will be placed, and is
initialized to zero in the declaration. This meant that backups for
meta_bg descriptors were erroneously written to the backup block group
descriptors in groups 1 and (desc_per_block-1).
Reproduction information:
mke2fs -Fq -t ext4 -b 1024 -O ^resize_inode /tmp/foo.img 16G
truncate -s 24G /tmp/foo.img
losetup /dev/loop0 /tmp/foo.img
mount /dev/loop0 /mnt
resize2fs /dev/loop0
umount /dev/loop0
dd if=/dev/zero of=/dev/loop0 bs=1024 count=2
e2fsck -fy /dev/loop0
losetup -d /dev/loop0
Signed-off-by: Andy Leiserson <andy@leiserson.org>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit 6934da9238 upstream.
There is a use-after-free possibility in __ext4_journal_stop() in the
case that we free the handle in the first jbd2_journal_stop() because
we're referencing handle->h_err afterwards. This was introduced in
9705acd63b and it is wrong. Fix it by
storing the handle->h_err value beforehand and avoid referencing
potentially freed handle.
Fixes: 9705acd63b
Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit 94426f4b96 upstream.
In ext4_zero_range(), removing a file's entire block range from the
extent status tree removes all records of that file's delalloc extents.
The delalloc accounting code uses this information, and its loss can
then lead to accounting errors and kernel warnings at writeback time and
subsequent file system damage. This is most noticeable on bigalloc
file systems where code in ext4_ext_map_blocks() handles cases where
delalloc extents share clusters with a newly allocated extent.
Because we're not deleting a block range and are correctly updating the
status of its associated extent, there is no need to remove anything
from the extent status tree.
When this patch is combined with an unrelated bug fix for
ext4_zero_range(), kernel warnings and e2fsck errors reported during
xfstests runs on bigalloc filesystems are greatly reduced without
introducing regressions on other xfstests-bld test scenarios.
Signed-off-by: Eric Whitney <enwlinux@gmail.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit a068acf2ee upstream.
Many file systems that implement the show_options hook fail to correctly
escape their output which could lead to unescaped characters (e.g. new
lines) leaking into /proc/mounts and /proc/[pid]/mountinfo files. This
could lead to confusion, spoofed entries (resulting in things like
systemd issuing false d-bus "mount" notifications), and who knows what
else. This looks like it would only be the root user stepping on
themselves, but it's possible weird things could happen in containers or
in other situations with delegated mount privileges.
Here's an example using overlay with setuid fusermount trusting the
contents of /proc/mounts (via the /etc/mtab symlink). Imagine the use
of "sudo" is something more sneaky:
$ BASE="ovl"
$ MNT="$BASE/mnt"
$ LOW="$BASE/lower"
$ UP="$BASE/upper"
$ WORK="$BASE/work/ 0 0
none /proc fuse.pwn user_id=1000"
$ mkdir -p "$LOW" "$UP" "$WORK"
$ sudo mount -t overlay -o "lowerdir=$LOW,upperdir=$UP,workdir=$WORK" none /mnt
$ cat /proc/mounts
none /root/ovl/mnt overlay rw,relatime,lowerdir=ovl/lower,upperdir=ovl/upper,workdir=ovl/work/ 0 0
none /proc fuse.pwn user_id=1000 0 0
$ fusermount -u /proc
$ cat /proc/mounts
cat: /proc/mounts: No such file or directory
This fixes the problem by adding new seq_show_option and
seq_show_option_n helpers, and updating the vulnerable show_option
handlers to use them as needed. Some, like SELinux, need to be open
coded due to unusual existing escape mechanisms.
[akpm@linux-foundation.org: add lost chunk, per Kees]
[keescook@chromium.org: seq_show_option should be using const parameters]
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Acked-by: Jan Kara <jack@suse.com>
Acked-by: Paul Moore <paul@paul-moore.com>
Cc: J. R. Okajima <hooanon05g@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[ luis: backported to 3.16:
- dropped changes to fs/overlayfs/super.c, net/ceph/ceph_common.c and to
cgroup_show_options() in kernel/cgroup.c
- adjusted context ]
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit c45653c341 upstream.
Switch ext4 to using sb_getblk_gfp with GFP_NOFS added to fix possible
deadlocks in the page writeback path.
Signed-off-by: Nikolay Borisov <kernel@kyup.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit 7444a072c3 upstream.
ext4_free_blocks is looping around the allocation request and mimics
__GFP_NOFAIL behavior without any allocation fallback strategy. Let's
remove the open coded loop and replace it with __GFP_NOFAIL. Without the
flag the allocator has no way to find out never-fail requirement and
cannot help in any way.
Signed-off-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit 8974fec7d7 upstream.
Currently ext4_ind_migrate() doesn't correctly handle a file which
contains a hole at the beginning of the file. This caused the migration
to be done incorrectly, and then if there is a subsequent following
delayed allocation write to the "hole", this would reclaim the same data
blocks again and results in fs corruption.
# assmuing 4k block size ext4, with delalloc enabled
# skip the first block and write to the second block
xfs_io -fc "pwrite 4k 4k" -c "fsync" /mnt/ext4/testfile
# converting to indirect-mapped file, which would move the data blocks
# to the beginning of the file, but extent status cache still marks
# that region as a hole
chattr -e /mnt/ext4/testfile
# delayed allocation writes to the "hole", reclaim the same data block
# again, results in i_blocks corruption
xfs_io -c "pwrite 0 4k" /mnt/ext4/testfile
umount /mnt/ext4
e2fsck -nf /dev/sda6
...
Inode 53, i_blocks is 16, should be 8. Fix? no
...
Signed-off-by: Eryu Guan <guaneryu@gmail.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit d6f123a929 upstream.
Currently the check in ext4_ind_migrate() is not enough before doing the
real conversion:
a) delayed allocated extents could bypass the check on eh->eh_entries
and eh->eh_depth
This can be demonstrated by this script
xfs_io -fc "pwrite 0 4k" -c "pwrite 8k 4k" /mnt/ext4/testfile
chattr -e /mnt/ext4/testfile
where testfile has two extents but still be converted to non-extent
based file format.
b) only extent length is checked but not the offset, which would result
in data lose (delalloc) or fs corruption (nodelalloc), because
non-extent based file only supports at most (12 + 2^10 + 2^20 + 2^30)
blocks
This can be demostrated by
xfs_io -fc "pwrite 5T 4k" /mnt/ext4/testfile
chattr -e /mnt/ext4/testfile
sync
If delalloc is enabled, dmesg prints
EXT4-fs warning (device dm-4): ext4_block_to_path:105: block 1342177280 > max in inode 53
EXT4-fs (dm-4): Delayed block allocation failed for inode 53 at logical offset 1342177280 with max blocks 1 with error 5
EXT4-fs (dm-4): This should not happen!! Data will be lost
If delalloc is disabled, e2fsck -nf shows corruption
Inode 53, i_size is 5497558142976, should be 4096. Fix? no
Fix the two issues by
a) forcing all delayed allocation blocks to be allocated before checking
eh->eh_depth and eh->eh_entries
b) limiting the last logical block of the extent is within direct map
Signed-off-by: Eryu Guan <guaneryu@gmail.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit 9705acd63b upstream.
On delalloc enabled file system on invalidatepage operation
in ext4_da_page_release_reservation() we want to clear the delayed
buffer and remove the extent covering the delayed buffer from the extent
status tree.
However currently there is a bug where on the systems with page size >
block size we will always remove extents from the start of the page
regardless where the actual delayed buffers are positioned in the page.
This leads to the errors like this:
EXT4-fs warning (device loop0): ext4_da_release_space:1225:
ext4_da_release_space: ino 13, to_free 1 with only 0 reserved data
blocks
This however can cause data loss on writeback time if the file system is
in ENOSPC condition because we're releasing reservation for someones
else delayed buffer.
Fix this by only removing extents that corresponds to the part of the
page we want to invalidate.
This problem is reproducible by the following fio receipt (however I was
only able to reproduce it with fio-2.1 or older.
[global]
bs=8k
iodepth=1024
iodepth_batch=60
randrepeat=1
size=1m
directory=/mnt/test
numjobs=20
[job1]
ioengine=sync
bs=1k
direct=1
rw=randread
filename=file1:file2
[job2]
ioengine=libaio
rw=randwrite
direct=1
filename=file1:file2
[job3]
bs=1k
ioengine=posixaio
rw=randwrite
direct=1
filename=file1:file2
[job5]
bs=1k
ioengine=sync
rw=randread
filename=file1:file2
[job7]
ioengine=libaio
rw=randwrite
filename=file1:file2
[job8]
ioengine=posixaio
rw=randwrite
filename=file1:file2
[job10]
ioengine=mmap
rw=randwrite
bs=1k
filename=file1:file2
[job11]
ioengine=mmap
rw=randwrite
direct=1
filename=file1:file2
Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit 292db1bc6c upstream.
ext4 isn't willing to map clusters to a non-extent file. Don't signal
this with an out of space error, since the FS will retry the
allocation (which didn't fail) forever. Instead, return EUCLEAN so
that the operation will fail immediately all the way back to userspace.
(The fix is either to run e2fsck -E bmap2extent, or to chattr +e the file.)
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit 89d96a6f8e upstream.
Normally all of the buffers will have been forced out to disk before
we call invalidate_bdev(), but there will be some cases, where a file
system operation was aborted due to an ext4_error(), where there may
still be some dirty buffers in the buffer cache for the device. So
try to force them out to memory before calling invalidate_bdev().
This fixes a warning triggered by generic/081:
WARNING: CPU: 1 PID: 3473 at /usr/projects/linux/ext4/fs/block_dev.c:56 __blkdev_put+0xb5/0x16f()
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit bdf96838ae upstream.
The commit cf108bca46: "ext4: Invert the locking order of page_lock
and transaction start" caused __ext4_journalled_writepage() to drop
the page lock before the page was written back, as part of changing
the locking order to jbd2_journal_start -> page_lock. However, this
introduced a potential race if there was a truncate racing with the
data=journalled writeback mode.
Fix this by grabbing the page lock after starting the journal handle,
and then checking to see if page had gotten truncated out from under
us.
This fixes a number of different warnings or BUG_ON's when running
xfstests generic/086 in data=journalled mode, including:
jbd2_journal_dirty_metadata: vdc-8: bad jh for block 115643: transaction (ee3fe7
c0, 164), jh->b_transaction ( (null), 0), jh->b_next_transaction ( (null), 0), jlist 0
- and -
kernel BUG at /usr/projects/linux/ext4/fs/jbd2/transaction.c:2200!
...
Call Trace:
[<c02b2ded>] ? __ext4_journalled_invalidatepage+0x117/0x117
[<c02b2de5>] __ext4_journalled_invalidatepage+0x10f/0x117
[<c02b2ded>] ? __ext4_journalled_invalidatepage+0x117/0x117
[<c027d883>] ? lock_buffer+0x36/0x36
[<c02b2dfa>] ext4_journalled_invalidatepage+0xd/0x22
[<c0229139>] do_invalidatepage+0x22/0x26
[<c0229198>] truncate_inode_page+0x5b/0x85
[<c022934b>] truncate_inode_pages_range+0x156/0x38c
[<c0229592>] truncate_inode_pages+0x11/0x15
[<c022962d>] truncate_pagecache+0x55/0x71
[<c02b913b>] ext4_setattr+0x4a9/0x560
[<c01ca542>] ? current_kernel_time+0x10/0x44
[<c026c4d8>] notify_change+0x1c7/0x2be
[<c0256a00>] do_truncate+0x65/0x85
[<c0226f31>] ? file_ra_state_init+0x12/0x29
- and -
WARNING: CPU: 1 PID: 1331 at /usr/projects/linux/ext4/fs/jbd2/transaction.c:1396
irty_metadata+0x14a/0x1ae()
...
Call Trace:
[<c01b879f>] ? console_unlock+0x3a1/0x3ce
[<c082cbb4>] dump_stack+0x48/0x60
[<c0178b65>] warn_slowpath_common+0x89/0xa0
[<c02ef2cf>] ? jbd2_journal_dirty_metadata+0x14a/0x1ae
[<c0178bef>] warn_slowpath_null+0x14/0x18
[<c02ef2cf>] jbd2_journal_dirty_metadata+0x14a/0x1ae
[<c02d8615>] __ext4_handle_dirty_metadata+0xd4/0x19d
[<c02b2f44>] write_end_fn+0x40/0x53
[<c02b4a16>] ext4_walk_page_buffers+0x4e/0x6a
[<c02b59e7>] ext4_writepage+0x354/0x3b8
[<c02b2f04>] ? mpage_release_unused_pages+0xd4/0xd4
[<c02b1b21>] ? wait_on_buffer+0x2c/0x2c
[<c02b5a4b>] ? ext4_writepage+0x3b8/0x3b8
[<c02b5a5b>] __writepage+0x10/0x2e
[<c0225956>] write_cache_pages+0x22d/0x32c
[<c02b5a4b>] ? ext4_writepage+0x3b8/0x3b8
[<c02b6ee8>] ext4_writepages+0x102/0x607
[<c019adfe>] ? sched_clock_local+0x10/0x10e
[<c01a8a7c>] ? __lock_is_held+0x2e/0x44
[<c01a8ad5>] ? lock_is_held+0x43/0x51
[<c0226dff>] do_writepages+0x1c/0x29
[<c0276bed>] __writeback_single_inode+0xc3/0x545
[<c0277c07>] writeback_sb_inodes+0x21f/0x36d
...
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit 2f974865ff upstream.
The following commit introduced a bug when checking for zero length extent
5946d08 ext4: check for overlapping extents in ext4_valid_extent_entries()
Zero length extent could pass the check if lblock is zero.
Adding the explicit check for zero length back.
Signed-off-by: Eryu Guan <guaneryu@gmail.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit 9d50659406 upstream.
Currently when journal restart fails, we'll have the h_transaction of
the handle set to NULL to indicate that the handle has been effectively
aborted. We handle this situation quietly in the jbd2_journal_stop() and just
free the handle and exit because everything else has been done before we
attempted (and failed) to restart the journal.
Unfortunately there are a number of problems with that approach
introduced with commit
41a5b91319 "jbd2: invalidate handle if jbd2_journal_restart()
fails"
First of all in ext4 jbd2_journal_stop() will be called through
__ext4_journal_stop() where we would try to get a hold of the superblock
by dereferencing h_transaction which in this case would lead to NULL
pointer dereference and crash.
In addition we're going to free the handle regardless of the refcount
which is bad as well, because others up the call chain will still
reference the handle so we might potentially reference already freed
memory.
Moreover it's expected that we'll get aborted handle as well as detached
handle in some of the journalling function as the error propagates up
the stack, so it's unnecessary to call WARN_ON every time we get
detached handle.
And finally we might leak some memory by forgetting to free reserved
handle in jbd2_journal_stop() in the case where handle was detached from
the transaction (h_transaction is NULL).
Fix the NULL pointer dereference in __ext4_journal_stop() by just
calling jbd2_journal_stop() quietly as suggested by Jan Kara. Also fix
the potential memory leak in jbd2_journal_stop() and use proper
handle refcounting before we attempt to free it to avoid use-after-free
issues.
And finally remove all WARN_ON(!transaction) from the code so that we do
not get random traces when something goes wrong because when journal
restart fails we will get to some of those functions.
Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit 280227a75b upstream.
fallocate() checks that the file is extent-based and returns
EOPNOTSUPP in case is not. Other tasks can convert from and to
indirect and extent so it's safe to check only after grabbing
the inode mutex.
Signed-off-by: Davide Italiano <dccitaliano@gmail.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit d2dc317d56 upstream.
Currently it is possible to lose whole file system block worth of data
when we hit the specific interaction with unwritten and delayed extents
in status extent tree.
The problem is that when we insert delayed extent into extent status
tree the only way to get rid of it is when we write out delayed buffer.
However there is a limitation in the extent status tree implementation
so that when inserting unwritten extent should there be even a single
delayed block the whole unwritten extent would be marked as delayed.
At this point, there is no way to get rid of the delayed extents,
because there are no delayed buffers to write out. So when a we write
into said unwritten extent we will convert it to written, but it still
remains delayed.
When we try to write into that block later ext4_da_map_blocks() will set
the buffer new and delayed and map it to invalid block which causes
the rest of the block to be zeroed loosing already written data.
For now we can fix this by simply not allowing to set delayed status on
written extent in the extent status tree. Also add WARN_ON() to make
sure that we notice if this happens in the future.
This problem can be easily reproduced by running the following xfs_io.
xfs_io -f -c "pwrite -S 0xaa 4096 2048" \
-c "falloc 0 131072" \
-c "pwrite -S 0xbb 65536 2048" \
-c "fsync" /mnt/test/fff
echo 3 > /proc/sys/vm/drop_caches
xfs_io -c "pwrite -S 0xdd 67584 2048" /mnt/test/fff
This can be theoretically also reproduced by at random by running fsx,
but it's not very reliable, though on machines with bigger page size
(like ppc) this can be seen more often (especially xfstest generic/127)
Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit 0f2af21aae upstream.
Currently there is a bug in zero range code which causes zero range
calls to only allocate block aligned portion of the range, while
ignoring the rest in some cases.
In some cases, namely if the end of the range is past i_size, we do
attempt to preallocate the last nonaligned block. However this might
cause kernel to BUG() in some carefully designed zero range requests
on setups where page size > block size.
Fix this problem by first preallocating the entire range, including
the nonaligned edges and converting the written extents to unwritten
in the next step. This approach will also give us the advantage of
having the range to be as linearly contiguous as possible.
Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: Moritz Muehlenhoff <jmm@debian.org>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit 713e8dde3e upstream.
We accidently aliased EXT4_EX_NOCACHE and EXT4_GET_CONVERT_UNWRITTEN
falgs, which apparently was hiding a bug that was unmasked when this
flag aliasing issue was addressed (see the subsequent commit). The
reproduction case was:
fsx -N 10000 -l 500000 -r 4096 -t 4096 -w 4096 -Z -R -W /vdb/junk
... which would cause fsx to report corruption in the data file.
The fix we have is a bit of an overkill, but I'd much rather be
conservative for now, and we can optimize ZERO_RANGE_FL handling
later. The fact that we need to zap the extent_status cache for the
inode is unfortunate, but correctness is far more important than
performance.
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: Namjae Jeon <namjae.jeon@samsung.com>
Cc: Moritz Muehlenhoff <jmm@debian.org>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit bd30d702fc upstream.
Commit b8a8684502 introduced an accidental flag aliasing between
EXT4_EX_NOCACHE and EXT4_GET_BLOCKS_CONVERT_UNWRITTEN.
Fortunately, this didn't introduce any untorward side effects --- we
got lucky. Nevertheless, fix this and leave a warning to hopefully
avoid this from happening in the future.
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: Moritz Muehlenhoff <jmm@debian.org>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit e12fb97222 upstream.
Previously commit 14ece1028b added a
support for for syncing parent directory of newly created inodes to
make sure that the inode is not lost after a power failure in
no-journal mode.
However this does not work in majority of cases, namely:
- if the directory has inline data
- if the directory is already indexed
- if the directory already has at least one block and:
- the new entry fits into it
- or we've successfully converted it to indexed
So in those cases we might lose the inode entirely even after fsync in
the no-journal mode. This also includes ext2 default mode obviously.
I've noticed this while running xfstest generic/321 and even though the
test should fail (we need to run fsck after a crash in no-journal mode)
I could not find a newly created entries even when if it was fsynced
before.
Fix this by adjusting the ext4_add_entry() successful exit paths to set
the inode EXT4_STATE_NEWENTRY so that fsync has the chance to fsync the
parent directory as well.
Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Frank Mayhar <fmayhar@google.com>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit 6f30b7e37a upstream.
Commit 4f579ae7de (ext4: fix punch hole on files with indirect
mapping) rewrote FALLOC_FL_PUNCH_HOLE for ext4 files with indirect
mapping. However, there are bugs in several corner cases. This fixes 5
distinct bugs:
1. When there is at least one entire level of indirection between the
start and end of the punch range and the end of the punch range is the
first block of its level, we can't return early; we have to free the
intervening levels.
2. When the end is at a higher level of indirection than the start and
ext4_find_shared returns a top branch for the end, we still need to free
the rest of the shared branch it returns; we can't decrement partial2.
3. When a punch happens within one level of indirection, we need to
converge on an indirect block that contains the start and end. However,
because the branches returned from ext4_find_shared do not necessarily
start at the same level (e.g., the partial2 chain will be shallower if
the last block occurs at the beginning of an indirect group), the walk
of the two chains can end up "missing" each other and freeing a bunch of
extra blocks in the process. This mismatch can be handled by first
making sure that the chains are at the same level, then walking them
together until they converge.
4. When the punch happens within one level of indirection and
ext4_find_shared returns a top branch for the start, we must free it,
but only if the end does not occur within that branch.
5. When the punch happens within one level of indirection and
ext4_find_shared returns a top branch for the end, then we shouldn't
free the block referenced by the end of the returned chain (this mirrors
the different levels case).
Signed-off-by: Omar Sandoval <osandov@osandov.com>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit 6050d47adc upstream.
When ext4_handle_dirty_dx_node() or ext4_handle_dirty_dirent_node()
fail, there's really something wrong with the fs and there's no point in
continuing further. Just return error from make_indexed_dir() in that
case. Also initialize frames array so that if we return early due to
error, dx_release() doesn't try to dereference uninitialized memory
(which could happen also due to error in do_split()).
Coverity-id: 741300
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit f8b3b59d4d upstream.
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
[ luis: backported to 3.16: useful for:
6050d47adc "ext4: bail out from make_indexed_dir() on first error" ]
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit 98c1a7593f upstream.
If metadata checksumming is turned on for the FS, we need to tell the
journal to use checksumming too.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit 599a9b77ab upstream.
When we fail to load block bitmap in __ext4_new_inode() we will
dereference NULL pointer in ext4_journal_get_write_access(). So check
for error from ext4_read_block_bitmap().
Coverity-id: 989065
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit 9378c6768e upstream.
When there are no meta block groups update_backups() will compute the
backup block in 32-bit arithmetics thus possibly overflowing the block
number and corrupting the filesystem. OTOH filesystems without meta
block groups larger than 16 TB should be rare. Fix the problem by doing
the counting in 64-bit arithmetics.
Coverity-id: 741252
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
commit 813d32f913 upstream.
Convert the ext4_has_group_desc_csum predicate to look for a checksum
driver instead of the metadata_csum flag and change the bg checksum
calculation function to look for GDT_CSUM before taking the crc16
path.
Without this patch, if we mount with ^uninit_bg,^metadata_csum and
later metadata_csum gets turned on by accident, the block group
checksum functions will incorrectly assume that checksumming is
enabled (metadata_csum) but that crc16 should be used
(!s_chksum_driver). This is totally wrong, so fix the predicate
and the checksum formula selection.
(Granted, if the metadata_csum feature bit gets enabled on a live FS
then something underhanded is going on, but we could at least avoid
writing garbage into the on-disk fields.)
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
