Currently we scan extent status trees of inodes until we reclaim nr_to_scan
extents. This can however require a lot of scanning when there are lots
of delayed extents (as those cannot be reclaimed).
Change shrinker to work as shrinkers are supposed to and *scan* only
nr_to_scan extents regardless of how many extents did we actually
reclaim. We however need to be careful and avoid scanning each status
tree from the beginning - that could lead to a situation where we would
not be able to reclaim anything at all when first nr_to_scan extents in
the tree are always unreclaimable. We remember with each inode offset
where we stopped scanning and continue from there when we next come
across the inode.
Note that we also need to update places calling __es_shrink() manually
to pass reasonable nr_to_scan to have a chance of reclaiming anything and
not just 1.
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Currently callers adding extents to extent status tree were responsible
for adding the inode to the list of inodes with freeable extents. This
is error prone and puts list handling in unnecessarily many places.
Just add inode to the list automatically when the first non-delay extent
is added to the tree and remove inode from the list when the last
non-delay extent is removed.
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
In this commit we discard the lru algorithm for inodes with extent
status tree because it takes significant effort to maintain a lru list
in extent status tree shrinker and the shrinker can take a long time to
scan this lru list in order to reclaim some objects.
We replace the lru ordering with a simple round-robin. After that we
never need to keep a lru list. That means that the list needn't be
sorted if the shrinker can not reclaim any objects in the first round.
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Signed-off-by: Zheng Liu <wenqing.lz@taobao.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Currently extent status tree doesn't cache extent hole when a write
looks up in extent tree to make sure whether a block has been allocated
or not. In this case, we don't put extent hole in extent cache because
later this extent might be removed and a new delayed extent might be
added back. But it will cause a defect when we do a lot of writes. If
we don't put extent hole in extent cache, the following writes also need
to access extent tree to look at whether or not a block has been
allocated. It brings a cache miss. This commit fixes this defect.
Also if the inode doesn't have any extent, this extent hole will be
cached as well.
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Signed-off-by: Zheng Liu <wenqing.lz@taobao.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
For bigalloc filesystems we have to check whether newly requested inode
block isn't already part of a cluster for which we already have delayed
allocation reservation. This check happens in ext4_ext_map_blocks() and
that function sets EXT4_MAP_FROM_CLUSTER if that's the case. However if
ext4_da_map_blocks() finds in extent cache information about the block,
we don't call into ext4_ext_map_blocks() and thus we always end up
getting new reservation even if the space for cluster is already
reserved. This results in overreservation and premature ENOSPC reports.
Fix the problem by checking for existing cluster reservation already in
ext4_da_map_blocks(). That simplifies the logic and actually allows us
to get rid of the EXT4_MAP_FROM_CLUSTER flag completely.
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
ext4_ext_remove_space() can incorrectly free a partial_cluster if
EAGAIN is encountered while truncating or punching. Extent removal
should be retried in this case.
It also fails to free a partial cluster when the punched region begins
at the start of a file on that unaligned cluster and where the entire
file has not been punched. Remove the requirement that all blocks in
the file must have been freed in order to free the partial cluster.
Signed-off-by: Eric Whitney <enwlinux@gmail.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Add some casts and rearrange a few statements for improved readability.
Some code can also be simplified and made more readable if we set
partial_cluster to 0 rather than to a negative value when we can tell
we've hit the left edge of the punched region.
Signed-off-by: Eric Whitney <enwlinux@gmail.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
The fix in commit ad6599ab3a ("ext4: fix premature freeing of
partial clusters split across leaf blocks"), intended to avoid
dereferencing an invalid extent pointer when determining whether a
partial cluster should be freed, wasn't quite good enough. Assure that
at least one extent remains at the start of the leaf once the hole has
been punched. Otherwise, the pointer to the extent to the right of the
hole will be invalid and a partial cluster will be incorrectly freed.
Set partial_cluster to 0 when we can tell we've hit the left edge of
the punched region within the leaf. This prevents incorrect freeing
of a partial cluster when ext4_ext_rm_leaf is called one last time
during extent tree traversal after the punched region has been removed.
Adjust comments to reflect code changes and a correction. Remove a bit
of dead code.
Signed-off-by: Eric Whitney <enwlinux@gmail.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
The partial_cluster variable is not always initialized correctly when
hole punching on bigalloc file systems. Although commit c063449394
("ext4: fix partial cluster handling for bigalloc file systems")
addressed the case where the right edge of the punched region and the
next extent to its right were within the same leaf, it didn't handle
the case where the next extent to its right is in the next leaf. This
causes xfstest generic/300 to fail.
Fix this by replacing the code in c0634493922 with a more general
solution that can continue the search for the first cluster to the
right of the punched region into the next leaf if present. If found,
partial_cluster is initialized to this cluster's negative value.
There's no need to determine if that cluster is actually shared; we
simply record it so its blocks won't be freed in the event it does
happen to be shared.
Also, minimize the burden on non-bigalloc file systems with some minor
code simplification.
Signed-off-by: Eric Whitney <enwlinux@gmail.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Xiaoguang Wang has reported sporadic EBUSY failures of ext4/302
Unfortunetly there is nothing we can do if some other task holds BH's
refenrence. So we must return EBUSY in this case. But we can try
kicking the journal to see if the other task releases the bh reference
after the commit is complete. Also decrease false positives by
properly checking for ENOSPC and retrying the allocation after kicking
the journal --- which is done by ext4_should_retry_alloc().
[ Modified by tytso to properly check for ENOSPC. ]
Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Pull VFS fixes from Al Viro:
"A bunch of assorted fixes, most of them followups to overlayfs merge"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
ovl: initialize ->is_cursor
Return short read or 0 at end of a raw device, not EIO
isofs: don't bother with ->d_op for normal case
isofs_cmp(): we'll never see a dentry for . or ..
overlayfs: fix lockdep misannotation
ovl: fix check for cursor
overlayfs: barriers for opening upper-layer directory
rcu: Provide counterpart to rcu_dereference() for non-RCU situations
staging: android: logger: Fix log corruption regression
Pull btrfs fixes from Chris Mason:
"Filipe is nailing down some problems with our skinny extent variation,
and Dave's patch fixes endian problems in the new super block checks"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
Btrfs: fix race that makes btrfs_lookup_extent_info miss skinny extent items
Btrfs: properly clean up btrfs_end_io_wq_cache
Btrfs: fix invalid leaf slot access in btrfs_lookup_extent()
btrfs: use macro accessors in superblock validation checks
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Merge tag 'ext4_for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4
Pull ext4 bugfixes from Ted Ts'o:
"A set of miscellaneous ext4 bug fixes for 3.18"
* tag 'ext4_for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
ext4: make ext4_ext_convert_to_initialized() return proper number of blocks
ext4: bail early when clearing inode journal flag fails
ext4: bail out from make_indexed_dir() on first error
jbd2: use a better hash function for the revoke table
ext4: prevent bugon on race between write/fcntl
ext4: remove extent status procfs files if journal load fails
ext4: disallow changing journal_csum option during remount
ext4: enable journal checksum when metadata checksum feature enabled
ext4: fix oops when loading block bitmap failed
ext4: fix overflow when updating superblock backups after resize
Pull quota and ext3 fixes from Jan Kara.
* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
fs, jbd: use a more generic hash function
quota: Properly return errors from dquot_writeback_dquots()
ext3: Don't check quota format when there are no quota files
Author: David Jeffery <djeffery@redhat.com>
Changes to the basic direct I/O code have broken the raw driver when reading
to the end of a raw device. Instead of returning a short read for a read that
extends partially beyond the device's end or 0 when at the end of the device,
these reads now return EIO.
The raw driver needs the same end of device handling as was added for normal
block devices. Using blkdev_read_iter, which has the needed size checks,
prevents the EIO conditions at the end of the device.
Signed-off-by: David Jeffery <djeffery@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
The man page for open(2) indicates that when O_CREAT is specified, the
'mode' argument applies only to future accesses to the file:
Note that this mode applies only to future accesses of the newly
created file; the open() call that creates a read-only file
may well return a read/write file descriptor.
The man page for open(2) implies that 'mode' is treated identically by
O_CREAT and O_TMPFILE.
O_TMPFILE, however, behaves differently:
int fd = open("/tmp", O_TMPFILE | O_RDWR, 0);
assert(fd == -1);
assert(errno == EACCES);
int fd = open("/tmp", O_TMPFILE | O_RDWR, 0600);
assert(fd > 0);
For O_CREAT, do_last() sets acc_mode to MAY_OPEN only:
if (*opened & FILE_CREATED) {
/* Don't check for write permission, don't truncate */
open_flag &= ~O_TRUNC;
will_truncate = false;
acc_mode = MAY_OPEN;
path_to_nameidata(path, nd);
goto finish_open_created;
}
But for O_TMPFILE, do_tmpfile() passes the full op->acc_mode to
may_open().
This patch lines up the behavior of O_TMPFILE with O_CREAT. After the
inode is created, may_open() is called with acc_mode = MAY_OPEN, in
do_tmpfile().
A different, but related glibc bug revealed the discrepancy:
https://sourceware.org/bugzilla/show_bug.cgi?id=17523
The glibc lazily loads the 'mode' argument of open() and openat() using
va_arg() only if O_CREAT is present in 'flags' (to support both the 2
argument and the 3 argument forms of open; same idea for openat()).
However, the glibc ignores the 'mode' argument if O_TMPFILE is in
'flags'.
On x86_64, for open(), it magically works anyway, as 'mode' is in
RDX when entering open(), and is still in RDX on SYSCALL, which is where
the kernel looks for the 3rd argument of a syscall.
But openat() is not quite so lucky: 'mode' is in RCX when entering the
glibc wrapper for openat(), while the kernel looks for the 4th argument
of a syscall in R10. Indeed, the syscall calling convention differs from
the regular calling convention in this respect on x86_64. So the kernel
sees mode = 0 when trying to use glibc openat() with O_TMPFILE, and
fails with EACCES.
Signed-off-by: Eric Rannaud <e@nanocritical.com>
Acked-by: Andy Lutomirski <luto@amacapital.net>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
ext4_ext_convert_to_initialized() can return more blocks than are
actually allocated from map->m_lblk in case where initial part of the
on-disk extent is zeroed out. Luckily this doesn't have serious
consequences because the caller currently uses the return value
only to unmap metadata buffers. Anyway this is a data
corruption/exposure problem waiting to happen so fix it.
Coverity-id: 1226848
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
When clearing inode journal flag, we call jbd2_journal_flush() to force
all the journalled data to their final locations. Currently we ignore
when this fails and continue clearing inode journal flag. This isn't a
big problem because when jbd2_journal_flush() fails, journal is likely
aborted anyway. But it can still lead to somewhat confusing results so
rather bail out early.
Coverity-id: 989044
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
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>
Cc: stable@vger.kernel.org
The old hash function didn't work well for 64-bit block numbers, and
used undefined (negative) shift right behavior. Use the generic
64-bit hash function instead.
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reported-by: Andrey Ryabinin <a.ryabinin@samsung.com>
If we can't load the journal, remove the procfs files for the extent
status information file to avoid leaking resources.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org
ext4 does not permit changing the metadata or journal checksum feature
flag while mounted. Until we decide to support that, don't allow a
remount to change the journal_csum flag (right now we silently fail to
change anything).
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
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>
Cc: stable@vger.kernel.org
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
Cc: stable@vger.kernel.org
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
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
CC: stable@vger.kernel.org
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Lukas Czerner <lczerner@redhat.com>
Merge misc fixes from Andrew Morton:
"21 fixes"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (21 commits)
mm/balloon_compaction: fix deflation when compaction is disabled
sh: fix sh770x SCIF memory regions
zram: avoid NULL pointer access in concurrent situation
mm/slab_common: don't check for duplicate cache names
ocfs2: fix d_splice_alias() return code checking
mm: rmap: split out page_remove_file_rmap()
mm: memcontrol: fix missed end-writeback page accounting
mm: page-writeback: inline account_page_dirtied() into single caller
lib/bitmap.c: fix undefined shift in __bitmap_shift_{left|right}()
drivers/rtc/rtc-bq32k.c: fix register value
memory-hotplug: clear pgdat which is allocated by bootmem in try_offline_node()
drivers/rtc/rtc-s3c.c: fix initialization failure without rtc source clock
kernel/kmod: fix use-after-free of the sub_info structure
drivers/rtc/rtc-pm8xxx.c: rework to support pm8941 rtc
mm, thp: fix collapsing of hugepages on madvise
drivers: of: add return value to of_reserved_mem_device_init()
mm: free compound page with correct order
gcov: add ARM64 to GCOV_PROFILE_ALL
fsnotify: next_i is freed during fsnotify_unmount_inodes.
mm/compaction.c: avoid premature range skip in isolate_migratepages_range
...
d_splice_alias() can return a valid dentry, NULL or an ERR_PTR.
Currently the code checks not for ERR_PTR and will cuase an oops in
ocfs2_dentry_attach_lock(). Fix this by using IS_ERR_OR_NULL().
Signed-off-by: Richard Weinberger <richard@nod.at>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
During file system stress testing on 3.10 and 3.12 based kernels, the
umount command occasionally hung in fsnotify_unmount_inodes in the
section of code:
spin_lock(&inode->i_lock);
if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) {
spin_unlock(&inode->i_lock);
continue;
}
As this section of code holds the global inode_sb_list_lock, eventually
the system hangs trying to acquire the lock.
Multiple crash dumps showed:
The inode->i_state == 0x60 and i_count == 0 and i_sb_list would point
back at itself. As this is not the value of list upon entry to the
function, the kernel never exits the loop.
To help narrow down problem, the call to list_del_init in
inode_sb_list_del was changed to list_del. This poisons the pointers in
the i_sb_list and causes a kernel to panic if it transverse a freed
inode.
Subsequent stress testing paniced in fsnotify_unmount_inodes at the
bottom of the list_for_each_entry_safe loop showing next_i had become
free.
We believe the root cause of the problem is that next_i is being freed
during the window of time that the list_for_each_entry_safe loop
temporarily releases inode_sb_list_lock to call fsnotify and
fsnotify_inode_delete.
The code in fsnotify_unmount_inodes attempts to prevent the freeing of
inode and next_i by calling __iget. However, the code doesn't do the
__iget call on next_i
if i_count == 0 or
if i_state & (I_FREEING | I_WILL_FREE)
The patch addresses this issue by advancing next_i in the above two cases
until we either find a next_i which we can __iget or we reach the end of
the list. This makes the handling of next_i more closely match the
handling of the variable "inode."
The time to reproduce the hang is highly variable (from hours to days.) We
ran the stress test on a 3.10 kernel with the proposed patch for a week
without failure.
During list_for_each_entry_safe, next_i is becoming free causing
the loop to never terminate. Advance next_i in those cases where
__iget is not done.
Signed-off-by: Jerry Hoemann <jerry.hoemann@hp.com>
Cc: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Cc: Ken Helias <kenhelias@firemail.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull block layer fixes from Jens Axboe:
"A small collection of fixes for the current kernel. This contains:
- Two error handling fixes from Jan Kara. One for null_blk on
failure to add a device, and the other for the block/scsi_ioctl
SCSI_IOCTL_SEND_COMMAND fixing up the error jump point.
- A commit added in the merge window for the bio integrity bits
unfortunately disabled merging for all requests if
CONFIG_BLK_DEV_INTEGRITY wasn't set. Reverse the logic, so that
integrity checking wont disallow merges when not enabled.
- A fix from Ming Lei for merging and generating too many segments.
This caused a BUG in virtio_blk.
- Two error handling printk() fixups from Robert Elliott, improving
the information given when we rate limit.
- Error handling fixup on elevator_init() failure from Sudip
Mukherjee.
- A fix from Tony Battersby, fixing up a memory leak in the
scatterlist handling with scsi-mq"
* 'for-linus' of git://git.kernel.dk/linux-block:
block: Fix merge logic when CONFIG_BLK_DEV_INTEGRITY is not defined
lib/scatterlist: fix memory leak with scsi-mq
block: fix wrong error return in elevator_init()
scsi: Fix error handling in SCSI_IOCTL_SEND_COMMAND
null_blk: Cleanup error recovery in null_add_dev()
blk-merge: recaculate segment if it isn't less than max segments
fs: clarify rate limit suppressed buffer I/O errors
fs: merge I/O error prints into one line
In an overlay directory that shadows an empty lower directory, say
/mnt/a/empty102, do:
touch /mnt/a/empty102/x
unlink /mnt/a/empty102/x
rmdir /mnt/a/empty102
It's actually harmless, but needs another level of nesting between
I_MUTEX_CHILD and I_MUTEX_NORMAL.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Tested-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
ovl_cache_entry.name is now an array not a pointer, so it makes no sense
test for it being NULL.
Detected by coverity.
From: Miklos Szeredi <mszeredi@suse.cz>
Fixes: 68bf861107 ("overlayfs: make ovl_cache_entry->name an array instead of
+pointer")
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
make sure that
a) all stores done by opening struct file don't leak past storing
the reference in od->upperfile
b) the lockless side has read dependency barrier
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
We have a race that can lead us to miss skinny extent items in the function
btrfs_lookup_extent_info() when the skinny metadata feature is enabled.
So basically the sequence of steps is:
1) We search in the extent tree for the skinny extent, which returns > 0
(not found);
2) We check the previous item in the returned leaf for a non-skinny extent,
and we don't find it;
3) Because we didn't find the non-skinny extent in step 2), we release our
path to search the extent tree again, but this time for a non-skinny
extent key;
4) Right after we released our path in step 3), a skinny extent was inserted
in the extent tree (delayed refs were run) - our second extent tree search
will miss it, because it's not looking for a skinny extent;
5) After the second search returned (with ret > 0), we look for any delayed
ref for our extent's bytenr (and we do it while holding a read lock on the
leaf), but we won't find any, as such delayed ref had just run and completed
after we released out path in step 3) before doing the second search.
Fix this by removing completely the path release and re-search logic. This is
safe, because if we seach for a metadata item and we don't find it, we have the
guarantee that the returned leaf is the one where the item would be inserted,
and so path->slots[0] > 0 and path->slots[0] - 1 must be the slot where the
non-skinny extent item is if it exists. The only case where path->slots[0] is
zero is when there are no smaller keys in the tree (i.e. no left siblings for
our leaf), in which case the re-search logic isn't needed as well.
This race has been present since the introduction of skinny metadata (change
3173a18f70).
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
Pull two nfsd fixes from Bruce Fields:
"One regression from the 3.16 xdr rewrite, one an older bug exposed by
a separate bug in the client's new SEEK code"
* 'for-3.18' of git://linux-nfs.org/~bfields/linux:
nfsd4: fix crash on unknown operation number
nfsd4: fix response size estimation for OP_SEQUENCE
In one of Dave's cleanup commits he forgot to call btrfs_end_io_wq_exit on
unload, which makes us unable to unload and then re-load the btrfs module. This
fixes the problem. Thanks,
Signed-off-by: Josef Bacik <jbacik@fb.com>
Reviewed-by: David Sterba <dsterba@suse.cz>
Reviewed-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
If we couldn't find our extent item, we accessed the current slot
(path->slots[0]) to check if it corresponds to an equivalent skinny
metadata item. However this slot could be beyond our last item in the
leaf (i.e. path->slots[0] >= btrfs_header_nritems(leaf)), in which case
we shouldn't process it.
Since btrfs_lookup_extent() is only used to find extent items for data
extents, fix this by removing completely the logic that looks up for an
equivalent skinny metadata item, since it can not exist.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
The initial patch c926093ec5 (btrfs: add more superblock checks)
did not properly use the macro accessors that wrap endianness and the
code would not work correctly on big endian machines.
Reported-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <clm@fb.com>
no sense having it a pointer - all instances have it pointing to
local variable in the same stack frame
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
d_splice_alias() callers expect it to either stash the inode reference
into a new alias, or drop the inode reference. That makes it possible
to just return d_splice_alias() result from ->lookup() instance, without
any extra housekeeping required.
Unfortunately, that should include the failure exits. If d_splice_alias()
returns an error, it leaves the dentry it has been given negative and
thus it *must* drop the inode reference. Easily fixed, but it goes way
back and will need backporting.
Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Add a simple read-only counter to super_block that indicates how deep this
is in the stack of filesystems. Previously ecryptfs was the only stackable
filesystem and it explicitly disallowed multiple layers of itself.
Overlayfs, however, can be stacked recursively and also may be stacked
on top of ecryptfs or vice versa.
To limit the kernel stack usage we must limit the depth of the
filesystem stack. Initially the limit is set to 2.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
