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2013-02-20Btrfs: use percpu counter for dirty metadata countMiao Xie
->dirty_metadata_bytes is accessed very frequently, so use percpu counter instead of the u64 variant to reduce the contention of the lock. This patch also fixed the problem that we access it without lock protection in __btrfs_btree_balance_dirty(), which may cause we skip the dirty pages flush. Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2013-02-20Btrfs: protect fs_info->alloc_startMiao Xie
fs_info->alloc_start is a 64bits variant, can be accessed by multi-task, but it is not protected strictly, it can be changed while we are accessing it. On 32bit machine, we will get wrong value because we access it by two instructions.(In fact, it is also possible that the same problem happens on the 64bit machine, because the compiler may split the 64bit operation into two 32bit operation.) For example: Assuming -> alloc_start is 0x0000 0000 0001 0000 at the beginning, then we remount and set ->alloc_start to 0x0000 0100 0000 0000. Task0 Task1 load high 32 bits set high 32 bits set low 32 bits load low 32 bits Task1 will get 0. This patch fixes this problem by using two locks to protect it fs_info->chunk_mutex sb->s_umount On the read side, we just need get one of these two locks, and on the write side, we must lock all of them. Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2013-02-20Btrfs: add a comment for fs_info->max_inlineMiao Xie
Though ->max_inline is a 64bit variant, and may be accessed by multi-task, but it is just suggestive number, so we needn't add anything to protect fs_info->max_inline, just add a comment to explain wny we don't use a lock to protect it. Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2013-02-20Btrfs: move fs/btrfs/ioctl.h to include/uapi/linux/btrfs.hFilipe Brandenburger
The header file will then be installed under /usr/include/linux so that userspace applications can refer to Btrfs ioctls by name and use the same structs used internally in the kernel. Signed-off-by: Filipe Brandenburger <filbranden@google.com> Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2013-02-20Btrfs: Check CAP_DAC_READ_SEARCH for BTRFS_IOC_INO_PATHSKusanagi Kouichi
CAP_DAC_READ_SEARCH overrides read and search permission check on file and directory. It seems fit for BTRFS_IOC_INO_PATHS. Signed-off-by: Kusanagi Kouichi <slash@ac.auone-net.jp> Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2013-02-20Revert "Btrfs: fix permissions of empty files not affected by umask"Josef Bacik
This reverts commit 2794ed013b3551cbae887ea1b93c52aaacb7370d. Wasn't supposed to get used in btrfs_mknod, it was supposed to be in btrfs_create, which was done in commit 9185aa587b7425f8f4520da2e66792f5f3c2b815. Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2013-02-20Btrfs: don't traverse the ordered operation list repeatedlyMiao Xie
btrfs_run_ordered_operations() needn't traverse the ordered operation list repeatedly, it is because the transaction commiter will invoke it again when there is no other writer in this transaction, it can ensure that no one can add new objects into the ordered operation list. Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2013-02-20Btrfs: traverse and flush the delalloc inodes onceMiao Xie
btrfs_start_delalloc_inodes() needn't traverse and flush the delalloc inodes repeatedly. It is because we can regard the data that the users write after we start delalloc inodes flush as the one which is after the delalloc inodes flush is done, and we can flush it next time. Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2013-02-20Btrfs: check the return value of btrfs_run_ordered_operations()Miao Xie
We forget to check the return value of btrfs_run_ordered_operations() when flushing all the pending stuffs, fix it. Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2013-02-20Btrfs: check the return value of btrfs_start_delalloc_inodes()Miao Xie
We forget to check the return value of btrfs_start_delalloc_inodes(), fix it. Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2013-02-20Btrfs: make raid attr array more readableMiao Xie
The current code of raid attr arry is hard to understand and it is easy to introduce some problem if we modify the array. So I changed it and made it more readable. Cc: Liu Bo <bo.li.liu@oracle.com> Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2013-02-20Btrfs: record first logical byte in memoryLiu Bo
This'd save us a rbtree search which may become expensive in large filesystem. Signed-off-by: Liu Bo <bo.li.liu@oracle.com> Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2013-02-20Btrfs: save us a read_lockLiu Bo
This does not change the logic of code, but can save us a read_lock. Signed-off-by: Liu Bo <bo.li.liu@oracle.com> Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2013-02-20Btrfs: use token to avoid times mapping extent bufferLiu Bo
The API in tree log code has done sort of changes, and it proves that we can benifit from using token, so do the same thing here. function_graph tracer's timer shows that it costs nearly half time of before(39.788us -> 22.391us). Signed-off-by: Liu Bo <bo.li.liu@oracle.com> Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2013-02-20Btrfs: kill unused argument of btrfs_pin_extent_for_log_replayLiu Bo
Argument 'trans' is not used any more. Signed-off-by: Liu Bo <bo.li.liu@oracle.com> Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2013-02-20Btrfs: kill unused argument of update_block_groupLiu Bo
Argument 'trans' is not used any more. Signed-off-by: Liu Bo <bo.li.liu@oracle.com> Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2013-02-20Btrfs: kill unused arguments of cache_block_groupLiu Bo
Argument 'trans' and 'root' are not used any more. Signed-off-by: Liu Bo <bo.li.liu@oracle.com> Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2013-02-20Btrfs: remove deprecated commentsLiu Bo
commit d53ba47484ed6245e640ee4bfe9d21e9bfc15765 (Btrfs: use commit root when loading free space cache) has remove the deadlock check, and the related comments can be removed as well. Signed-off-by: Liu Bo <bo.li.liu@oracle.com> Reviewed-by: David Sterba <dsterba@suse.cz> Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2013-02-20Btrfs: don't re-enter when allocating a chunkJosef Bacik
If we start running low on metadata space we will try to allocate a chunk, which could then try to allocate a chunk to add the device entry. The thing is we allocate a chunk before we try really hard to make the allocation, so we should be able to find space for the device entry. Add a flag to the trans handle so we know we're currently allocating a chunk so we can just bail out if we try to allocate another chunk. Thanks, Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2013-02-20Btrfs: wait on ordered extents at the last possible momentJosef Bacik
Since we don't actually copy the extent information from the source tree in the fast case we don't need to wait for ordered io to be completed in order to fsync, we just need to wait for the io to be completed. So when we're logging our file just attach all of the ordered extents to the log, and then when the log syncs just wait for IO_DONE on the ordered extents and then write the super. Thanks, Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2013-02-20Btrfs: fix trivial error in btrfs_ioctl_resize()Miao Xie
This patch fixes the following problem: - improper return value - unnecessary read-only check Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2013-02-20Btrfs: use wrapper page_offsetMiao Xie
Use wrapper page_offset to get byte-offset into filesystem object for page. Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com> Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2013-02-20Btrfs: flush all dirty inodes if writeback can not startMiao Xie
We may try to flush some dirty pages when there is no enough space to reserve. But it is possible that this operation fails, in order to get enough space to reserve successfully, we will sync all the delalloc file. This operation is safe, we needn't worry about the case that the filesystem goes from r/w to r/o. because the filesystem should guarantee all the dirty pages have been written into the disk after it becomes readonly, so the sync operation will do nothing if the filesystem is already readonly. Though it may waste lots of time, as a corner case, we needn't care. Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2013-02-20Btrfs: make delayed ref lock logic more readableMiao Xie
Locking and unlocking delayed ref mutex are in the different functions, and the name of lock functions is not uniform, so the readability is not so good, this patch optimizes the lock logic and makes it more readable. Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2013-02-20Btrfs: fix lots of orphan inodes when the space is not enoughMiao Xie
We're running into having 50-100 orphans left over with xfstests 83 because of ENOSPC when trying to start the transaction for the inode update. But in fact, it makes no sense in updating the inode for the new size while we're deleting the stupid thing. This patch fixes this problem. Reported-by: Josef Bacik <jbacik@fusionio.com> Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2013-02-20Btrfs: cleanup similar code in delayed inodeMiao Xie
The delayed item commit code in several functions is similar, so cleanup it. Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2013-02-20Btrfs: use common work instead of delayed workMiao Xie
Since we do not want to delay the async transaction commit, we should use common work, not delayed work. Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
2013-02-20Btrfs: cleanup unnecessary clear when freeing a transaction or a trans handleMiao Xie
We clear the transaction object and the trans handle when they are about to be freed, it is unnecessary, cleanup it. Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
2013-02-20Btrfs: use slabs for delayed reference allocationMiao Xie
The delayed reference allocation is in the fast path of the IO, so use slabs to improve the speed of the allocation. And besides that, it can do check for leaked objects when the module is removed. Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
2013-02-19Merge branch 'timers-core-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull timer changes from Ingo Molnar: "Main changes: - ntp: Add CONFIG_RTC_SYSTOHC: a generic RTC driver facility complementing the existing CONFIG_RTC_HCTOSYS, which uses NTP to keep the hardware clock updated. - posix-timers: Fix clock_adjtime to always return timex data on success. This is changing the ABI, but no breakage was expected and found - caution is warranted nevertheless. - platform persistent clock improvements/cleanups. - clockevents: refactor timer broadcast handling to be more generic and less duplicated with matching architecture code (mostly ARM motivated.) - various fixes and cleanups" * 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: timers/x86/hpet: Use HPET_COUNTER to specify the hpet counter in vread_hpet() posix-cpu-timers: Fix nanosleep task_struct leak clockevents: Fix generic broadcast for FEAT_C3STOP time, Fix setting of hardware clock in NTP code hrtimer: Prevent hrtimer_enqueue_reprogram race clockevents: Add generic timer broadcast function clockevents: Add generic timer broadcast receiver timekeeping: Switch HAS_PERSISTENT_CLOCK to ALWAYS_USE_PERSISTENT_CLOCK x86/time/rtc: Don't print extended CMOS year when reading RTC x86: Select HAS_PERSISTENT_CLOCK on x86 timekeeping: Add CONFIG_HAS_PERSISTENT_CLOCK option rtc: Skip the suspend/resume handling if persistent clock exist timekeeping: Add persistent_clock_exist flag posix-timers: Fix clock_adjtime to always return timex data on success Round the calculated scale factor in set_cyc2ns_scale() NTP: Add a CONFIG_RTC_SYSTOHC configuration MAINTAINERS: Update John Stultz's email time: create __getnstimeofday for WARNless calls
2013-02-19Merge branch 'sched-core-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler changes from Ingo Molnar: "Main changes: - scheduler side full-dynticks (user-space execution is undisturbed and receives no timer IRQs) preparation changes that convert the cputime accounting code to be full-dynticks ready, from Frederic Weisbecker. - Initial sched.h split-up changes, by Clark Williams - select_idle_sibling() performance improvement by Mike Galbraith: " 1 tbench pair (worst case) in a 10 core + SMT package: pre 15.22 MB/sec 1 procs post 252.01 MB/sec 1 procs " - sched_rr_get_interval() ABI fix/change. We think this detail is not used by apps (so it's not an ABI in practice), but lets keep it under observation. - misc RT scheduling cleanups, optimizations" * 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (24 commits) sched/rt: Add <linux/sched/rt.h> header to <linux/init_task.h> cputime: Remove irqsave from seqlock readers sched, powerpc: Fix sched.h split-up build failure cputime: Restore CPU_ACCOUNTING config defaults for PPC64 sched/rt: Move rt specific bits into new header file sched/rt: Add a tuning knob to allow changing SCHED_RR timeslice sched: Move sched.h sysctl bits into separate header sched: Fix signedness bug in yield_to() sched: Fix select_idle_sibling() bouncing cow syndrome sched/rt: Further simplify pick_rt_task() sched/rt: Do not account zero delta_exec in update_curr_rt() cputime: Safely read cputime of full dynticks CPUs kvm: Prepare to add generic guest entry/exit callbacks cputime: Use accessors to read task cputime stats cputime: Allow dynamic switch between tick/virtual based cputime accounting cputime: Generic on-demand virtual cputime accounting cputime: Move default nsecs_to_cputime() to jiffies based cputime file cputime: Librarize per nsecs resolution cputime definitions cputime: Avoid multiplication overflow on utime scaling context_tracking: Export context state for generic vtime ... Fix up conflict in kernel/context_tracking.c due to comment additions.
2013-02-19Merge branch 'testing' of github.com:ceph/ceph-client into into linux-3.8-cephAlex Elder
2013-02-19ceph: remove a few bogus declarationsAlex Elder
There are three ceph page vector functions declared in "fs/ceph/super.h" that don't belong there. They're probably left over from some long-ago code reorganization. They're properly declared in "include/linux/ceph/libceph.h" so just delete the ones in "super.h". This and the next few commits resolve: http://tracker.ceph.com/issues/4053 Signed-off-by: Alex Elder <elder@inktank.com> Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
2013-02-19NLM: Ensure that we resend all pending blocking locks after a reclaimTrond Myklebust
Currently, nlmclnt_lock will break out of the for(;;) loop when the reclaimer wakes up the blocking lock thread by setting nlm_lck_denied_grace_period. This causes the lock request to fail with an ENOLCK error. The intention was always to ensure that we resend the lock request after the grace period has expired. Reported-by: Wangyuan Zhang <Wangyuan.Zhang@netapp.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> Cc: stable@vger.kernel.org
2013-02-19locking: Various static lock initializer fixesThomas Gleixner
The static lock initializers want to be fed the proper name of the lock and not some random string. In mainline random strings are obfuscating the readability of debug output, but for RT they prevent the spinlock substitution. Fix it up. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2013-02-18net: proc: remove proc_net_removeGao feng
proc_net_remove has been replaced by remove_proc_entry. we can remove it now. Signed-off-by: Gao feng <gaofeng@cn.fujitsu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-02-18net: proc: remove proc_net_fops_createGao feng
proc_net_fops_create has been replaced by proc_create, we can remove it now. Signed-off-by: Gao feng <gaofeng@cn.fujitsu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-02-18libceph: update ceph_mds_state_name() and ceph_mds_op_name()Alex Elder
Update ceph_mds_state_name() and ceph_mds_op_name() to include the newly-added definitions in "ceph_fs.h", and to match its counterpart in the user space code. Signed-off-by: Alex Elder <elder@inktank.com> Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
2013-02-18ceph: kill ceph_osdc_new_request() "num_reply" parameterAlex Elder
The "num_reply" parameter to ceph_osdc_new_request() is never used inside that function, so get rid of it. Note that ceph_sync_write() passes 2 for that argument, while all other callers pass 1. It doesn't matter, but perhaps someone should verify this doesn't indicate a problem. Signed-off-by: Alex Elder <elder@inktank.com> Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
2013-02-18ceph: kill ceph_osdc_writepages() "flags" parameterAlex Elder
There is only one caller of ceph_osdc_writepages(), and it always passes 0 as its "flags" argument. Get rid of that argument and replace its use in ceph_osdc_writepages() with 0. Signed-off-by: Alex Elder <elder@inktank.com> Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
2013-02-18ceph: kill ceph_osdc_writepages() "dosync" parameterAlex Elder
There is only one caller of ceph_osdc_writepages(), and it always passes 0 as its "dosync" argument. Get rid of that argument and replace its use in ceph_osdc_writepages() with 0. Signed-off-by: Alex Elder <elder@inktank.com> Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
2013-02-18ceph: kill ceph_osdc_writepages() "nofail" parameterAlex Elder
There is only one caller of ceph_osdc_writepages(), and it always passes the value true as its "nofail" argument. Get rid of that argument and replace its use in ceph_osdc_writepages() with the constant value true. This and a number of cleanup patches that follow resolve: http://tracker.ceph.com/issues/4126 Signed-off-by: Alex Elder <elder@inktank.com> Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
2013-02-18ext4: fix xattr block allocation/release with bigallocLukas Czerner
Currently when new xattr block is created or released we we would call dquot_free_block() or dquot_alloc_block() respectively, among the else decrementing or incrementing the number of blocks assigned to the inode by one block. This however does not work for bigalloc file system because we always allocate/free the whole cluster so we have to count with that in dquot_free_block() and dquot_alloc_block() as well. Use the clusters-to-blocks conversion EXT4_C2B() when passing number of blocks to the dquot_alloc/free functions to fix the problem. The problem has been revealed by xfstests #117 (and possibly others). Signed-off-by: Lukas Czerner <lczerner@redhat.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Reviewed-by: Eric Sandeen <sandeen@redhat.com> Cc: stable@vger.kernel.org
2013-02-18ext4: reclaim extents from extent status treeZheng Liu
Although extent status is loaded on-demand, we also need to reclaim extent from the tree when we are under a heavy memory pressure because in some cases fragmented extent tree causes status tree costs too much memory. Here we maintain a lru list in super_block. When the extent status of an inode is accessed and changed, this inode will be move to the tail of the list. The inode will be dropped from this list when it is cleared. In the inode, a counter is added to count the number of cached objects in extent status tree. Here only written/unwritten/hole extent is counted because delayed extent doesn't be reclaimed due to fiemap, bigalloc and seek_data/hole need it. The counter will be increased as a new extent is allocated, and it will be decreased as a extent is freed. In this commit we use normal shrinker framework to reclaim memory from the status tree. ext4_es_reclaim_extents_count() traverses the lru list to count the number of reclaimable extents. ext4_es_shrink() tries to reclaim written/unwritten/hole extents from extent status tree. The inode that has been shrunk is moved to the tail of lru list. Signed-off-by: Zheng Liu <wenqing.lz@taobao.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Cc: Jan kara <jack@suse.cz>
2013-02-18ext4: adjust some functions for reclaiming extents from extent status treeZheng Liu
This commit changes some interfaces in extent status tree because we need to use inode to count the cached objects in a extent status tree. Signed-off-by: Zheng Liu <wenqing.lz@taobao.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Cc: Jan kara <jack@suse.cz>
2013-02-18ext4: remove single extent cacheZheng Liu
Single extent cache could be removed because we have extent status tree as a extent cache, and it would be better. Signed-off-by: Zheng Liu <wenqing.lz@taobao.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Cc: Jan kara <jack@suse.cz>
2013-02-18ext4: lookup block mapping in extent status treeZheng Liu
After tracking all extent status, we already have a extent cache in memory. Every time we want to lookup a block mapping, we can first try to lookup it in extent status tree to avoid a potential disk I/O. A new function called ext4_es_lookup_extent is defined to finish this work. When we try to lookup a block mapping, we always call ext4_map_blocks and/or ext4_da_map_blocks. So in these functions we first try to lookup a block mapping in extent status tree. A new flag EXT4_GET_BLOCKS_NO_PUT_HOLE is used in ext4_da_map_blocks in order not to put a hole into extent status tree because this hole will be converted to delayed extent in the tree immediately. Signed-off-by: Zheng Liu <wenqing.lz@taobao.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Cc: Jan kara <jack@suse.cz>
2013-02-18ext4: track all extent status in extent status treeZheng Liu
By recording the phycisal block and status, extent status tree is able to track the status of every extents. When we call _map_blocks functions to lookup an extent or create a new written/unwritten/delayed extent, this extent will be inserted into extent status tree. We don't load all extents from disk in alloc_inode() because it costs too much memory, and if a file is opened and closed frequently it will takes too much time to load all extent information. So currently when we create/lookup an extent, this extent will be inserted into extent status tree. Hence, the extent status tree may not comprehensively contain all of the extents found in the file. Here a condition we need to take care is that an extent might contains unwritten and delayed status simultaneously because an extent is delayed allocated and could be allocated by fallocate. At this time we need to keep delayed status because later we need to update delayed reservation space using it. Signed-off-by: Zheng Liu <wenqing.lz@taobao.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Cc: Jan kara <jack@suse.cz>
2013-02-18ext4: let ext4_ext_map_blocks return EXT4_MAP_UNWRITTEN flagZheng Liu
This commit lets ext4_ext_map_blocks return EXT4_MAP_UNWRITTEN flag because in later commit ext4_map_blocks needs to use this flag to determine the extent status. Signed-off-by: Zheng Liu <wenqing.lz@taobao.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Reviewed-by: Jan Kara <jack@suse.cz>
2013-02-18ext4: rename and improbe ext4_es_find_extent()Zheng Liu
This commit renames ext4_es_find_extent with ext4_es_find_delayed_extent and improve this function. First, we split input and output parameter. Second, this function never return the first block of the next delayed extent after 'es'. Signed-off-by: Zheng Liu <wenqing.lz@taobao.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Cc: Jan kara <jack@suse.cz>