Pull ext3 improvements, cleanups, reiserfs fix from Jan Kara:
"various cleanups for ext2, ext3, udf, isofs, a documentation update
for quota, and a fix of a race in reiserfs readdir implementation"
* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
reiserfs: fix race in readdir
ext2: acl: remove unneeded include of linux/capability.h
ext3: explicitly remove inode from orphan list after failed direct io
fs/isofs/inode.c add __init to init_inodecache()
ext3: Speedup WB_SYNC_ALL pass
fs/quota/Kconfig: Update filesystems
ext3: Update outdated comment before ext3_ordered_writepage()
ext3: Update PF_MEMALLOC handling in ext3_write_inode()
ext2/3: use prandom_u32() instead of get_random_bytes()
ext3: remove an unneeded check in ext3_new_blocks()
ext3: remove unneeded check in ext3_ordered_writepage()
fs: Mark function as static in ext3/xattr_security.c
fs: Mark function as static in ext3/dir.c
fs: Mark function as static in ext2/xattr_security.c
ext3: Add __init macro to init_inodecache
ext2: Add __init macro to init_inodecache
udf: Add __init macro to init_inodecache
fs: udf: parse_options: blocksize check
Both affs and isofs check for blocksize integrity during
parse_options.Do the same thing for udf.
Valid values : 512, 1024, 2048 or 4096 bytes.
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Jan Kara <jack@suse.cz>
The UDF driver was not strict enough about checking the IDs in the
VSDs when mounting, which resulted in reading through all the sectors
of the block device in some unfortunate cases. Eg, trying to mount my
uninitialized 200G SSD partition (all 0xFF bytes) took ~350 minutes to
fail, because the code expected some of the valid IDs or a zero byte.
During this, the mount couldn't be killed, sync from the cmdline
blocked, and the machine froze into the shutdown. Valid filesystems
(extX, btrfs, ntfs) were rejected by the mere accident of having a
zero byte at just the right place in some of their sectors, close
enough to the beginning not to generate excess I/O. The fix adds a
hard limit on the VSD sector offset, adds the two missing VSD IDs, and
stops scanning when encountering an invalid ID. Also replaced the
magic number 32768 with a more meaningful #define, and supressed the
bogus message about failing to read the first sector if no UDF fs was
detected.
Signed-off-by: Peter A. Felvegi <petschy@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
A user has reported an oops in udf_statfs() that was caused by
numOfPartitions entry in LVID structure being corrupted. Fix the problem
by verifying whether numOfPartitions makes sense at least to the extent
that LVID fits into a single block as it should.
Reported-by: Juergen Weigert <jw@suse.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Refuse RW mount of udf filesystem. So far we just silently changed it
to RO mount but when the media is writeable, block layer won't notice
this change and thus will think device is used RW and will block eject
button of the drive. That is unexpected by users because for
non-writeable media eject button works just fine.
Userspace mount(8) command handles this just fine and retries mounting
with MS_RDONLY set so userspace shouldn't see any regression. Plus any
tool mounting udf is likely confronted with the case of read-only
media where block layer already refuses to mount the filesystem without
MS_RDONLY set so our behavior shouldn't be anything new for it.
Reported-by: Hui Wang <hui.wang@canonical.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Change all function used in filesystem discovery during mount to user
standard kernel return values - -errno on error, 0 on success instead
of 1 on failure and 0 on success. This allows us to pass error number
(not just failure / success) so we can abort device scanning earlier
in case of errors like EIO or ENOMEM . Also we will be able to return
EROFS in case writeable mount is requested but writing isn't supported.
Signed-off-by: Jan Kara <jack@suse.cz>
Somehow I failed to add the MODULE_ALIAS_FS for cifs, hostfs, hpfs,
squashfs, and udf despite what I thought were my careful checks :(
Add them now.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
struct udf_bitmap has array of buffer pointers attached to it. The code
unnecessarily used s_block_bitmap as a pointer to the array instead of
the standard trick of using 0 length array in the declaration. Change
that to make code more readable and actually shrink the structure by one
pointer.
Signed-off-by: Jan Kara <jack@suse.cz>
This patch implements extent caching in case of file reading.
While reading a file, currently, UDF reads metadata serially
which takes a lot of time depending on the number of extents present
in the file. Caching last accessd extent improves metadata read time.
Instead of reading file metadata from start, now we read from
the cached extent.
This patch considerably improves the time spent by CPU in kernel mode.
For example, while reading a 10.9 GB file using dd:
Time before applying patch:
11677022208 bytes (10.9GB) copied, 1529.748921 seconds, 7.3MB/s
real 25m 29.85s
user 0m 12.41s
sys 15m 34.75s
Time after applying patch:
11677022208 bytes (10.9GB) copied, 1469.338231 seconds, 7.6MB/s
real 24m 29.44s
user 0m 15.73s
sys 3m 27.61s
[JK: Fix bh refcounting issues, simplify initialization]
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Ashish Sangwan <a.sangwan@samsung.com>
Signed-off-by: Bonggil Bak <bgbak@samsung.com>
Signed-off-by: Jan Kara <jack@suse.cz>
So far we just marked the buffer as dirty and left writing on flusher thread
but especially on opening that opens possible race window where we could write
other modified fs structures to disk before we mark filesystem as open. So sync
LVID buffer to disk after opening and closing fs.
Reported-by: Steve Nickel <snickel58@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
This patch fixes a regression caused by commit bff943af6f "udf: Fix memory
leak when mounting" due to which it was triggering a kernel null point
dereference in case of interrupted mount OR when allocating memory to
sbi->s_partmaps failed in function udf_sb_alloc_partition_maps.
Reported-and-tested-by: James Hogan <james@albanarts.com>
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Ashish Sangwan <a.sangwan@samsung.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Pull vfs update from Al Viro:
- big one - consolidation of descriptor-related logics; almost all of
that is moved to fs/file.c
(BTW, I'm seriously tempted to rename the result to fd.c. As it is,
we have a situation when file_table.c is about handling of struct
file and file.c is about handling of descriptor tables; the reasons
are historical - file_table.c used to be about a static array of
struct file we used to have way back).
A lot of stray ends got cleaned up and converted to saner primitives,
disgusting mess in android/binder.c is still disgusting, but at least
doesn't poke so much in descriptor table guts anymore. A bunch of
relatively minor races got fixed in process, plus an ext4 struct file
leak.
- related thing - fget_light() partially unuglified; see fdget() in
there (and yes, it generates the code as good as we used to have).
- also related - bits of Cyrill's procfs stuff that got entangled into
that work; _not_ all of it, just the initial move to fs/proc/fd.c and
switch of fdinfo to seq_file.
- Alex's fs/coredump.c spiltoff - the same story, had been easier to
take that commit than mess with conflicts. The rest is a separate
pile, this was just a mechanical code movement.
- a few misc patches all over the place. Not all for this cycle,
there'll be more (and quite a few currently sit in akpm's tree)."
Fix up trivial conflicts in the android binder driver, and some fairly
simple conflicts due to two different changes to the sock_alloc_file()
interface ("take descriptor handling from sock_alloc_file() to callers"
vs "net: Providing protocol type via system.sockprotoname xattr of
/proc/PID/fd entries" adding a dentry name to the socket)
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (72 commits)
MAX_LFS_FILESIZE should be a loff_t
compat: fs: Generic compat_sys_sendfile implementation
fs: push rcu_barrier() from deactivate_locked_super() to filesystems
btrfs: reada_extent doesn't need kref for refcount
coredump: move core dump functionality into its own file
coredump: prevent double-free on an error path in core dumper
usb/gadget: fix misannotations
fcntl: fix misannotations
ceph: don't abuse d_delete() on failure exits
hypfs: ->d_parent is never NULL or negative
vfs: delete surplus inode NULL check
switch simple cases of fget_light to fdget
new helpers: fdget()/fdput()
switch o2hb_region_dev_write() to fget_light()
proc_map_files_readdir(): don't bother with grabbing files
make get_file() return its argument
vhost_set_vring(): turn pollstart/pollstop into bool
switch prctl_set_mm_exe_file() to fget_light()
switch xfs_find_handle() to fget_light()
switch xfs_swapext() to fget_light()
...
There's no reason to call rcu_barrier() on every
deactivate_locked_super(). We only need to make sure that all delayed rcu
free inodes are flushed before we destroy related cache.
Removing rcu_barrier() from deactivate_locked_super() affects some fast
paths. E.g. on my machine exit_group() of a last process in IPC
namespace takes 0.07538s. rcu_barrier() takes 0.05188s of that time.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Pull user namespace changes from Eric Biederman:
"This is a mostly modest set of changes to enable basic user namespace
support. This allows the code to code to compile with user namespaces
enabled and removes the assumption there is only the initial user
namespace. Everything is converted except for the most complex of the
filesystems: autofs4, 9p, afs, ceph, cifs, coda, fuse, gfs2, ncpfs,
nfs, ocfs2 and xfs as those patches need a bit more review.
The strategy is to push kuid_t and kgid_t values are far down into
subsystems and filesystems as reasonable. Leaving the make_kuid and
from_kuid operations to happen at the edge of userspace, as the values
come off the disk, and as the values come in from the network.
Letting compile type incompatible compile errors (present when user
namespaces are enabled) guide me to find the issues.
The most tricky areas have been the places where we had an implicit
union of uid and gid values and were storing them in an unsigned int.
Those places were converted into explicit unions. I made certain to
handle those places with simple trivial patches.
Out of that work I discovered we have generic interfaces for storing
quota by projid. I had never heard of the project identifiers before.
Adding full user namespace support for project identifiers accounts
for most of the code size growth in my git tree.
Ultimately there will be work to relax privlige checks from
"capable(FOO)" to "ns_capable(user_ns, FOO)" where it is safe allowing
root in a user names to do those things that today we only forbid to
non-root users because it will confuse suid root applications.
While I was pushing kuid_t and kgid_t changes deep into the audit code
I made a few other cleanups. I capitalized on the fact we process
netlink messages in the context of the message sender. I removed
usage of NETLINK_CRED, and started directly using current->tty.
Some of these patches have also made it into maintainer trees, with no
problems from identical code from different trees showing up in
linux-next.
After reading through all of this code I feel like I might be able to
win a game of kernel trivial pursuit."
Fix up some fairly trivial conflicts in netfilter uid/git logging code.
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (107 commits)
userns: Convert the ufs filesystem to use kuid/kgid where appropriate
userns: Convert the udf filesystem to use kuid/kgid where appropriate
userns: Convert ubifs to use kuid/kgid
userns: Convert squashfs to use kuid/kgid where appropriate
userns: Convert reiserfs to use kuid and kgid where appropriate
userns: Convert jfs to use kuid/kgid where appropriate
userns: Convert jffs2 to use kuid and kgid where appropriate
userns: Convert hpfs to use kuid and kgid where appropriate
userns: Convert btrfs to use kuid/kgid where appropriate
userns: Convert bfs to use kuid/kgid where appropriate
userns: Convert affs to use kuid/kgid wherwe appropriate
userns: On alpha modify linux_to_osf_stat to use convert from kuids and kgids
userns: On ia64 deal with current_uid and current_gid being kuid and kgid
userns: On ppc convert current_uid from a kuid before printing.
userns: Convert s390 getting uid and gid system calls to use kuid and kgid
userns: Convert s390 hypfs to use kuid and kgid where appropriate
userns: Convert binder ipc to use kuids
userns: Teach security_path_chown to take kuids and kgids
userns: Add user namespace support to IMA
userns: Convert EVM to deal with kuids and kgids in it's hmac computation
...
In case we detect a problem and bail out, we fail to set "ret" to a
nonzero value, and udf_load_logicalvol will mistakenly report success.
Signed-off-by: Nikola Pajkovsky <npajkovs@redhat.com>
Signed-off-by: Jan Kara <jack@suse.cz>
If s_lvid_bh is not freed and set to NULL before re-scanning partition
with default block size, we might end up using wrong lvid in case
s_lvid_bh is not updated in udf_load_logicalvolint during rescan.
Signed-off-by: Ashish Sangwan <ashish.sangwan2@gmail.com>
Signed-off-by: Namjae Jeon <linkinjeon@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
When a partition table length is corrupted to be close to 1 << 32, the
check for its length may overflow on 32-bit systems and we will think
the length is valid. Later on the kernel can crash trying to read beyond
end of buffer. Fix the check to avoid possible overflow.
CC: stable@vger.kernel.org
Reported-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Jan Kara <jack@suse.cz>
When we are mounting filesystem, we can load one partition table before
finding out that we cannot complete processing of logical volume descriptor
and trying the reserve descriptor. Free the table properly before trying
the reserve descriptor.
Signed-off-by: Jan Kara <jack@suse.cz>
The UDF file-system does not need the 's_dirt' superblock flag because it does
not define the 'write_super()' method. This flag was set to 1 in few places and
set to 0 in '->sync_fs()' and was basically useless. Stop using it because it
is on its way out.
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Check provided length of partition table so that (possibly maliciously)
corrupted partition table cannot cause accessing data beyond current buffer.
Signed-off-by: Jan Kara <jack@suse.cz>
Pull ext3, UDF, and quota fixes from Jan Kara:
"A couple of ext3 & UDF fixes and also one improvement in quota
locking."
* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
ext3: fix start and len arguments handling in ext3_trim_fs()
udf: Fix deadlock in udf_release_file()
udf: Fix file entry logicalBlocksRecorded
udf: Fix handling of i_blocks
quota: Make quota code not call tty layer with dqptr_sem held
udf: Init/maintain file entry checkpoint field
ext3: Update ctime in ext3_splice_branch() only when needed
ext3: Don't call dquot_free_block() if we don't update anything
udf: Remove unnecessary OOM messages
New field of struct super_block - ->s_max_links. Maximal allowed
value of ->i_nlink or 0; in the latter case all checks still need
to be done in ->link/->mkdir/->rename instances. Note that this
limit applies both to directoris and to non-directories.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Per call site OOM messages are unnecessary.
k.alloc and v.alloc failures use dump_stack().
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Jan Kara <jack@suse.cz>
* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
ext2/3/4: delete unneeded includes of module.h
ext{3,4}: Fix potential race when setversion ioctl updates inode
udf: Mark LVID buffer as uptodate before marking it dirty
ext3: Don't warn from writepage when readonly inode is spotted after error
jbd: Remove j_barrier mutex
reiserfs: Force inode evictions before umount to avoid crash
reiserfs: Fix quota mount option parsing
udf: Treat symlink component of type 2 as /
udf: Fix deadlock when converting file from in-ICB one to normal one
udf: Cleanup calling convention of inode_getblk()
ext2: Fix error handling on inode bitmap corruption
ext3: Fix error handling on inode bitmap corruption
ext3: replace ll_rw_block with other functions
ext3: NULL dereference in ext3_evict_inode()
jbd: clear revoked flag on buffers before a new transaction started
ext3: call ext3_mark_recovery_complete() when recovery is really needed
When we hit EIO while writing LVID, the buffer uptodate bit is cleared.
This then results in an anoying warning from mark_buffer_dirty() when we
write the buffer again. So just set uptodate flag unconditionally.
Reviewed-by: Namjae Jeon <linkinjeon@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
note re mount options: fmask and dmask are explicitly truncated to 12bit,
UDF_INVALID_MODE just needs to be guaranteed to differ from any such value.
And umask is used only in &= with umode_t, so we ignore other bits anyway.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Seeing that just about every destructor got that INIT_LIST_HEAD() copied into
it, there is no point whatsoever keeping this INIT_LIST_HEAD in inode_init_once();
the cost of taking it into inode_init_always() will be negligible for pipes
and sockets and negative for everything else. Not to mention the removal of
boilerplate code from ->destroy_inode() instances...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
It is not necessary to load mirror metadata FE when metadata FE is OK. So try
to read it only the first time udf_get_pblock_meta25() fails to map the block
from metadata FE.
Signed-off-by: Ashish Sangwan <ashishsangwan2@gmail.com>
Signed-off-by: Namjae Jeon <linkinjeon@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Just whitespace and argument alignment.
Introduce some checkpatch warnings that deserve to be ignored.
Reviewed-by: NamJae Jeon <linkinjeon@gmail.com>
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Use %pV and remove a static buffer to save some text space and fix possible
issues when several processes call error reporting function in parallel. Also
change error level from KERN_CRIT to KERN_ERR.
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Use the current logging styles.
Convert a few printks that should have been udf_warn and udf_err.
Coalesce formats. Add #define pr_fmt.
Move an #include "udfdecls.h" above other includes in udftime.c
so pr_fmt works correctly. Strip prefixes from conversions as appropriate.
Reorder logging definitions in udfdecl.h
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Rename udf_warning to udf_warn for consistency with normal logging
uses of pr_warn.
Rename function udf_warning to _udf_warn.
Remove __func__ from uses and move __func__ to a new udf_warn
macro that calls _udf_warn.
Add \n's to uses of udf_warn, remove \n from _udf_warn.
Coalesce formats.
Reviewed-by: NamJae Jeon <linkinjeon@gmail.com>
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Rename udf_error to udf_err for consistency with normal logging
uses of pr_err.
Rename function udf_err to _udf_err.
Remove __func__ from uses and move __func__ to a new udf_err
macro that calls _udf_err.
Some of the udf_error uses had \n terminations, some did not so
standardize \n's to udf_err uses, remove \n from _udf_err function.
Coalesce udf_err formats.
One message prefixed with udf_read_super is now prefixed with
udf_fill_super.
Reviewed-by: NamJae Jeon <linkinjeon@gmail.com>
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Jan Kara <jack@suse.cz>
If there is a problem with a scratched disc or loader, it's valuable to know
which error occurred.
Convert some debug messages to udf_error, neaten those messages too.
Add the calculated tag checksum and the read checksum to error message.
Make udf_error a public function and move the logging prototypes together.
Original-patch-by: NamJae Jeon <linkinjeon@gmail.com>
Reviewed-by: NamJae Jeon <linkinjeon@gmail.com>
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Jan Kara <jack@suse.cz>
* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-udf-2.6:
UDF: Close small mem leak in udf_find_entry()
udf: Fix directory corruption after extent merging
udf: Protect udf_file_aio_write from possible races
udf: Remove unnecessary bkl usages
udf: Use of s_alloc_mutex to serialize udf_relocate_blocks() execution
udf: Replace bkl with the UDF_I(inode)->i_data_sem for protect udf_inode_info struct
udf: Remove BKL from free space counting functions
udf: Call udf_add_free_space() for more blocks at once in udf_free_blocks()
udf: Remove BKL from udf_put_super() and udf_remount_fs()
udf: Protect default inode credentials by rwlock
udf: Protect all modifications of LVID with s_alloc_mutex
udf: Move handling of uniqueID into a helper function and protect it by a s_alloc_mutex
udf: Remove BKL from udf_update_inode
udf: Convert UDF_SB(sb)->s_flags to use bitops
fs/udf: Add printf format/argument verification
fs/udf: Use vzalloc
(Evil merge: this also removes the BKL dependency from the Kconfig file)
RCU free the struct inode. This will allow:
- Subsequent store-free path walking patch. The inode must be consulted for
permissions when walking, so an RCU inode reference is a must.
- sb_inode_list_lock to be moved inside i_lock because sb list walkers who want
to take i_lock no longer need to take sb_inode_list_lock to walk the list in
the first place. This will simplify and optimize locking.
- Could remove some nested trylock loops in dcache code
- Could potentially simplify things a bit in VM land. Do not need to take the
page lock to follow page->mapping.
The downsides of this is the performance cost of using RCU. In a simple
creat/unlink microbenchmark, performance drops by about 10% due to inability to
reuse cache-hot slab objects. As iterations increase and RCU freeing starts
kicking over, this increases to about 20%.
In cases where inode lifetimes are longer (ie. many inodes may be allocated
during the average life span of a single inode), a lot of this cache reuse is
not applicable, so the regression caused by this patch is smaller.
The cache-hot regression could largely be avoided by using SLAB_DESTROY_BY_RCU,
however this adds some complexity to list walking and store-free path walking,
so I prefer to implement this at a later date, if it is shown to be a win in
real situations. I haven't found a regression in any non-micro benchmark so I
doubt it will be a problem.
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
The udf_readdir(), udf_lookup(), udf_create(), udf_mknod(), udf_mkdir(),
udf_rmdir(), udf_link(), udf_get_parent() and udf_unlink() seems already
adequately protected by i_mutex held by VFS invoking calls. The udf_rename()
instead should be already protected by lock_rename again by VFS. The
udf_ioctl(), udf_fill_super() and udf_evict_inode() don't requires any further
protection.
This work was supported by a hardware donation from the CE Linux Forum.
Signed-off-by: Alessio Igor Bogani <abogani@texware.it>
Signed-off-by: Jan Kara <jack@suse.cz>
Replace bkl with the UDF_I(inode)->i_data_sem rw semaphore in
udf_release_file(), udf_symlink(), udf_symlink_filler(), udf_get_block(),
udf_block_map(), and udf_setattr(). The rule now is that any operation
on regular file's or symlink's extents (or generally allocation information
including goal block) needs to hold i_data_sem.
This work was supported by a hardware donation from the CE Linux Forum.
Signed-off-by: Alessio Igor Bogani <abogani@texware.it>
Signed-off-by: Jan Kara <jack@suse.cz>
udf_count_free_bitmap() does not need BKL because bitmaps are in a fixed
place on disk and so we can count set bits without serialization.
udf_count_free_table() is now protected by s_alloc_mutex instead of BKL
to get a consistent view of free space extents.
Signed-off-by: Jan Kara <jack@suse.cz>
udf_put_super() does not need BKL because the filesystem is shut down so
there's nothing to race with. The credential changes in udf_remount_fs()
and LVID changes are now protected by dedicated locks so we can remove BKL
from this function as well.
Signed-off-by: Jan Kara <jack@suse.cz>
Superblock carries credentials (uid, gid, etc.) which are used as default
values in __udf_read_inode() when media does not provide these. These
credentials can change during remount so we protect them by a rwlock so that
each inode gets a consistent set of credentials.
Signed-off-by: Jan Kara <jack@suse.cz>
