summaryrefslogtreecommitdiffstats
path: root/fs/ext4/extents_status.c (follow)
Commit message (Collapse)AuthorAgeFilesLines
* ext4: fix reserved cluster accounting in __es_remove_extent()Ye Bin2022-12-091-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When bigalloc is enabled, reserved cluster accounting for delayed allocation is handled in extent_status.c. With a corrupted file system, it's possible for this accounting to be incorrect, dsicovered by Syzbot: EXT4-fs error (device loop0): ext4_validate_block_bitmap:398: comm rep: bg 0: block 5: invalid block bitmap EXT4-fs (loop0): Delayed block allocation failed for inode 18 at logical offset 0 with max blocks 32 with error 28 EXT4-fs (loop0): This should not happen!! Data will be lost EXT4-fs (loop0): Total free blocks count 0 EXT4-fs (loop0): Free/Dirty block details EXT4-fs (loop0): free_blocks=0 EXT4-fs (loop0): dirty_blocks=32 EXT4-fs (loop0): Block reservation details EXT4-fs (loop0): i_reserved_data_blocks=2 EXT4-fs (loop0): Inode 18 (00000000845cd634): i_reserved_data_blocks (1) not cleared! Above issue happens as follows: Assume: sbi->s_cluster_ratio = 16 Step1: Insert delay block [0, 31] -> ei->i_reserved_data_blocks=2 Step2: ext4_writepages mpage_map_and_submit_extent -> return failed mpage_release_unused_pages -> to release [0, 30] ext4_es_remove_extent -> remove lblk=0 end=30 __es_remove_extent -> len1=0 len2=31-30=1 __es_remove_extent: ... if (len2 > 0) { ... if (len1 > 0) { ... } else { es->es_lblk = end + 1; es->es_len = len2; ... } if (count_reserved) count_rsvd(inode, lblk, ...); goto out; -> will return but didn't calculate 'reserved' ... Step3: ext4_destroy_inode -> trigger "i_reserved_data_blocks (1) not cleared!" To solve above issue if 'len2>0' call 'get_rsvd()' before goto out. Reported-by: syzbot+05a0f0ccab4a25626e38@syzkaller.appspotmail.com Fixes: 8fcc3a580651 ("ext4: rework reserved cluster accounting when invalidating pages") Signed-off-by: Ye Bin <yebin10@huawei.com> Reviewed-by: Eric Whitney <enwlinux@gmail.com> Link: https://lore.kernel.org/r/20221208033426.1832460-2-yebin@huaweicloud.com Signed-off-by: Theodore Ts'o <tytso@mit.edu> Cc: stable@kernel.org
* ext4: replace kmem_cache_create with KMEM_CACHEJunChao Sun2022-12-091-6/+2
| | | | | | | | | | Replace kmem_cache_create with KMEM_CACHE macro that guaranteed struct alignment Signed-off-by: JunChao Sun <sunjunchao2870@gmail.com> Reviewed-by: Jan Kara <jack@suse.cz> Link: https://lore.kernel.org/r/20221109153822.80250-1-sunjunchao2870@gmail.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* ext4: factor out ext4_free_ext_path()Ye Bin2022-10-011-2/+1
| | | | | | | | | | Factor out ext4_free_ext_path() to free extent path. As after previous patch 'ext4_ext_drop_refs()' is only used in 'extents.c', so make it static. Signed-off-by: Ye Bin <yebin10@huawei.com> Reviewed-by: Jan Kara <jack@suse.cz> Link: https://lore.kernel.org/r/20220924021211.3831551-3-yebin10@huawei.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* mm: shrinkers: provide shrinkers with namesRoman Gushchin2022-07-041-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently shrinkers are anonymous objects. For debugging purposes they can be identified by count/scan function names, but it's not always useful: e.g. for superblock's shrinkers it's nice to have at least an idea of to which superblock the shrinker belongs. This commit adds names to shrinkers. register_shrinker() and prealloc_shrinker() functions are extended to take a format and arguments to master a name. In some cases it's not possible to determine a good name at the time when a shrinker is allocated. For such cases shrinker_debugfs_rename() is provided. The expected format is: <subsystem>-<shrinker_type>[:<instance>]-<id> For some shrinkers an instance can be encoded as (MAJOR:MINOR) pair. After this change the shrinker debugfs directory looks like: $ cd /sys/kernel/debug/shrinker/ $ ls dquota-cache-16 sb-devpts-28 sb-proc-47 sb-tmpfs-42 mm-shadow-18 sb-devtmpfs-5 sb-proc-48 sb-tmpfs-43 mm-zspool:zram0-34 sb-hugetlbfs-17 sb-pstore-31 sb-tmpfs-44 rcu-kfree-0 sb-hugetlbfs-33 sb-rootfs-2 sb-tmpfs-49 sb-aio-20 sb-iomem-12 sb-securityfs-6 sb-tracefs-13 sb-anon_inodefs-15 sb-mqueue-21 sb-selinuxfs-22 sb-xfs:vda1-36 sb-bdev-3 sb-nsfs-4 sb-sockfs-8 sb-zsmalloc-19 sb-bpf-32 sb-pipefs-14 sb-sysfs-26 thp-deferred_split-10 sb-btrfs:vda2-24 sb-proc-25 sb-tmpfs-1 thp-zero-9 sb-cgroup2-30 sb-proc-39 sb-tmpfs-27 xfs-buf:vda1-37 sb-configfs-23 sb-proc-41 sb-tmpfs-29 xfs-inodegc:vda1-38 sb-dax-11 sb-proc-45 sb-tmpfs-35 sb-debugfs-7 sb-proc-46 sb-tmpfs-40 [roman.gushchin@linux.dev: fix build warnings] Link: https://lkml.kernel.org/r/Yr+ZTnLb9lJk6fJO@castle Reported-by: kernel test robot <lkp@intel.com> Link: https://lkml.kernel.org/r/20220601032227.4076670-4-roman.gushchin@linux.dev Signed-off-by: Roman Gushchin <roman.gushchin@linux.dev> Cc: Christophe JAILLET <christophe.jaillet@wanadoo.fr> Cc: Dave Chinner <dchinner@redhat.com> Cc: Hillf Danton <hdanton@sina.com> Cc: Kent Overstreet <kent.overstreet@gmail.com> Cc: Muchun Song <songmuchun@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* ext4: correct the cache_nr in tracepoint ext4_es_shrink_exitZhang Yi2021-06-231-0/+1
| | | | | | | | | | | | | The cache_cnt parameter of tracepoint ext4_es_shrink_exit means the remaining cache count after shrink, but now it is the cache count before shrink, fix it by read sbi->s_extent_cache_cnt again. Fixes: 1ab6c4997e04 ("fs: convert fs shrinkers to new scan/count API") Cc: stable@vger.kernel.org # 3.12+ Signed-off-by: Zhang Yi <yi.zhang@huawei.com> Reviewed-by: Jan Kara <jack@suse.cz> Link: https://lore.kernel.org/r/20210522103045.690103-3-yi.zhang@huawei.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* ext4: remove check for zero nr_to_scan in ext4_es_scan()Zhang Yi2021-06-231-3/+0
| | | | | | | | | | | | | After converting fs shrinkers to new scan/count API, we are no longer pass zero nr_to_scan parameter to detect the number of objects to free, just remove this check. Fixes: 1ab6c4997e04 ("fs: convert fs shrinkers to new scan/count API") Cc: stable@vger.kernel.org # 3.12+ Signed-off-by: Zhang Yi <yi.zhang@huawei.com> Reviewed-by: Jan Kara <jack@suse.cz> Link: https://lore.kernel.org/r/20210522103045.690103-2-yi.zhang@huawei.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* ext4: fast commit recovery pathHarshad Shirwadkar2020-10-221-0/+24
| | | | | | | | | | | | | | | This patch adds fast commit recovery path support for Ext4 file system. We add several helper functions that are similar in spirit to e2fsprogs journal recovery path handlers. Example of such functions include - a simple block allocator, idempotent block bitmap update function etc. Using these routines and the fast commit log in the fast commit area, the recovery path (ext4_fc_replay()) performs fast commit log recovery. Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Harshad Shirwadkar <harshadshirwadkar@gmail.com> Link: https://lore.kernel.org/r/20201015203802.3597742-8-harshadshirwadkar@gmail.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* ext4: remove unnecessary comparisons to boolJason Yan2020-06-041-1/+1
| | | | | | | | | | | | Fix the following coccicheck warning: fs/ext4/extents_status.c:1057:5-28: WARNING: Comparison to bool fs/ext4/inode.c:2314:18-24: WARNING: Comparison to bool Signed-off-by: Jason Yan <yanaijie@huawei.com> Reviewed-by: Ritesh Harjani <riteshh@linux.ibm.com> Link: https://lore.kernel.org/r/20200420042918.19459-1-yanaijie@huawei.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* ext4: use percpu_counters for extent_status cache hits/missesYang Guo2019-08-281-13/+24
| | | | | | | | | | | | | | | | | | | | | | @es_stats_cache_hits and @es_stats_cache_misses are accessed frequently in ext4_es_lookup_extent function, it would influence the ext4 read/write performance in NUMA system. Let's optimize it using percpu_counter, it is profitable for the performance. The test command is as below: fio -name=randwrite -numjobs=8 -filename=/mnt/test1 -rw=randwrite -ioengine=libaio -direct=1 -iodepth=64 -sync=0 -norandommap -group_reporting -runtime=120 -time_based -bs=4k -size=5G And the result is better 10% than the initial implement: without the patch,IOPS=197k, BW=770MiB/s (808MB/s)(90.3GiB/120002msec) with the patch, IOPS=218k, BW=852MiB/s (894MB/s)(99.9GiB/120002msec) Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: Eric Biggers <ebiggers@kernel.org> Signed-off-by: Yang Guo <guoyang2@huawei.com> Signed-off-by: Shaokun Zhang <zhangshaokun@hisilicon.com>
* ext4: rework reserved cluster accounting when invalidating pagesEric Whitney2019-08-231-97/+349
| | | | | | | | | | | | | | | | | | | The goal of this patch is to remove two references to the buffer delay bit in ext4_da_page_release_reservation() as part of a larger effort to remove all such references from ext4. These two references are principally used to reduce the reserved block/cluster count when pages are invalidated as a result of truncating, punching holes, or collapsing a block range in a file. The entire function is removed and replaced with code in ext4_es_remove_extent() that reduces the reserved count as a side effect of removing a block range from delayed and not unwritten extents in the extent status tree as is done when truncating, punching holes, or collapsing ranges. The code is written to minimize the number of searches descending from rb tree roots for scalability. Signed-off-by: Eric Whitney <enwlinux@gmail.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* ext4: add new ioctl EXT4_IOC_GET_ES_CACHETheodore Ts'o2019-08-111-0/+10
| | | | | | | | For debugging reasons, it's useful to know the contents of the extent cache. Since the extent cache contains much of what is in the fiemap ioctl, use an fiemap-style interface to return this information. Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* ext4: add a new ioctl EXT4_IOC_CLEAR_ES_CACHETheodore Ts'o2019-08-111-0/+28
| | | | | | | | The new ioctl EXT4_IOC_CLEAR_ES_CACHE will force an inode's extent status cache to be cleared out. This is intended for use for debugging. Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* ext4: remove redundant assignment to nodeColin Ian King2019-06-201-1/+0
| | | | | | | | | | | Pointer 'node' is assigned a value that is never read, node is later overwritten when it re-assigned a different value inside the while-loop. The assignment is redundant and can be removed. Addresses-Coverity: ("Unused value") Signed-off-by: Colin Ian King <colin.king@canonical.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Jan Kara <jack@suse.cz>
* ext4: use BUG() instead of BUG_ON(1)Arnd Bergmann2019-04-071-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BUG_ON(1) leads to bogus warnings from clang when CONFIG_PROFILE_ANNOTATED_BRANCHES is set: fs/ext4/inode.c:544:4: error: variable 'retval' is used uninitialized whenever 'if' condition is false [-Werror,-Wsometimes-uninitialized] BUG_ON(1); ^~~~~~~~~ include/asm-generic/bug.h:61:36: note: expanded from macro 'BUG_ON' ^~~~~~~~~~~~~~~~~~~ include/linux/compiler.h:48:23: note: expanded from macro 'unlikely' ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ fs/ext4/inode.c:591:6: note: uninitialized use occurs here if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED) { ^~~~~~ fs/ext4/inode.c:544:4: note: remove the 'if' if its condition is always true BUG_ON(1); ^ include/asm-generic/bug.h:61:32: note: expanded from macro 'BUG_ON' ^ fs/ext4/inode.c:502:12: note: initialize the variable 'retval' to silence this warning Change it to BUG() so clang can see that this code path can never continue. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Jan Kara <jack@suse.cz>
* ext4: fix reserved cluster accounting at page invalidation timeEric Whitney2018-10-011-0/+90
| | | | | | | | | | Add new code to count canceled pending cluster reservations on bigalloc file systems and to reduce the cluster reservation count on all file systems using delayed allocation. This replaces old code in ext4_da_page_release_reservations that was incorrect. Signed-off-by: Eric Whitney <enwlinux@gmail.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* ext4: reduce reserved cluster count by number of allocated clustersEric Whitney2018-10-011-0/+175
| | | | | | | | | | | | | | | | | | | | | | | | | | | Ext4 does not always reduce the reserved cluster count by the number of clusters allocated when mapping a delayed extent. It sometimes adds back one or more clusters after allocation if delalloc blocks adjacent to the range allocated by ext4_ext_map_blocks() share the clusters newly allocated for that range. However, this overcounts the number of clusters needed to satisfy future mapping requests (holding one or more reservations for clusters that have already been allocated) and premature ENOSPC and quota failures, etc., result. Ext4 also does not reduce the reserved cluster count when allocating clusters for non-delayed allocated writes that have previously been reserved for delayed writes. This also results in overcounts. To make it possible to handle reserved cluster accounting for fallocated regions in the same manner as used for other non-delayed writes, do the reserved cluster accounting for them at the time of allocation. In the current code, this is only done later when a delayed extent sharing the fallocated region is finally mapped. Address comment correcting handling of unsigned long long constant from Jan Kara's review of RFC version of this patch. Signed-off-by: Eric Whitney <enwlinux@gmail.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* ext4: fix reserved cluster accounting at delayed write timeEric Whitney2018-10-011-0/+53
| | | | | | | | | | | | | | The code in ext4_da_map_blocks sometimes reserves space for more delayed allocated clusters than it should, resulting in premature ENOSPC, exceeded quota, and inaccurate free space reporting. Fix this by checking for written and unwritten blocks shared in the same cluster with the newly delayed allocated block. A cluster reservation should not be made for a cluster for which physical space has already been allocated. Signed-off-by: Eric Whitney <enwlinux@gmail.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* ext4: add new pending reservation mechanismEric Whitney2018-10-011-0/+187
| | | | | | | | | | Add new pending reservation mechanism to help manage reserved cluster accounting. Its primary function is to avoid the need to read extents from the disk when invalidating pages as a result of a truncate, punch hole, or collapse range operation. Signed-off-by: Eric Whitney <enwlinux@gmail.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* ext4: generalize extents status tree search functionsEric Whitney2018-10-011-18/+131
| | | | | | | | | | | | | | | | | | Ext4 contains a few functions that are used to search for delayed extents or blocks in the extents status tree. Rather than duplicate code to add new functions to search for extents with different status values, such as written or a combination of delayed and unwritten, generalize the existing code to search for caller-specified extents status values. Also, move this code into extents_status.c where it is better associated with the data structures it operates upon, and where it can be more readily used to implement new extents status tree functions that might want a broader scope for i_es_lock. Three missing static specifiers in RFC version of patch reported and fixed by Fengguang Wu <fengguang.wu@intel.com>. Signed-off-by: Eric Whitney <enwlinux@gmail.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* ext4: remove NULL check before calling kmem_cache_destroy()Sean Fu2018-05-211-2/+1
| | | | | Signed-off-by: Sean Fu <fxinrong@gmail.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* License cleanup: add SPDX GPL-2.0 license identifier to files with no licenseGreg Kroah-Hartman2017-11-021-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* scripts/spelling.txt: add "comsume(r)" pattern and fix typo instancesMasahiro Yamada2017-02-281-1/+1
| | | | | | | | | | | | | | | | Fix typos and add the following to the scripts/spelling.txt: comsume||consume comsumer||consumer comsuming||consuming I see some variable names with this pattern, but this commit is only touching comment blocks to avoid unexpected impact. Link: http://lkml.kernel.org/r/1481573103-11329-19-git-send-email-yamada.masahiro@socionext.com Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ext4: remove trailing \n from ext4_warning/ext4_error callsJakub Wilk2016-04-271-1/+1
| | | | | | | Messages passed to ext4_warning() or ext4_error() don't need trailing newlines, because these function add the newlines themselves. Signed-off-by: Jakub Wilk <jwilk@jwilk.net>
* ext4: fix setting of referenced bit in ext4_es_lookup_extent()Jan Kara2016-03-101-2/+2
| | | | | | | | | | We were setting referenced bit on the extent structure we return from ext4_es_lookup_extent() which is just a private structure on stack. Thus setting had no effect. Set the bit in the structure in the status tree instead. Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* ext4: move procfs registration code to fs/ext4/sysfs.cTheodore Ts'o2015-09-231-58/+2
| | | | | | | | | This allows us to refactor the procfs code, which saves a bit of compiled space. More importantly it isolates most of the procfs support code into a single file, so it's easier to #ifdef it out if the proc file system has been disabled. Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* ext4: fix data corruption caused by unwritten and delayed extentsLukas Czerner2015-05-031-0/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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> Cc: stable@vger.kernel.org
* ext4: remove unused header filesSheng Yong2015-04-031-2/+0
| | | | | | | | Remove unused header files and header files which are included in ext4.h. Signed-off-by: Sheng Yong <shengyong1@huawei.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* ext4: introduce aging to extent status treeJan Kara2014-11-251-5/+17
| | | | | | | | | | Introduce a simple aging to extent status tree. Each extent has a REFERENCED bit which gets set when the extent is used. Shrinker then skips entries with referenced bit set and clears the bit. Thus frequently used extents have higher chances of staying in memory. Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* ext4: cleanup flag definitions for extent status treeJan Kara2014-11-251-0/+2
| | | | | | | | | | | Currently flags for extent status tree are defined twice, once shifted and once without a being shifted. Consolidate these definitions into one place and make some computations automatic to make adding flags less error prone. Compiler should be clever enough to figure out these are constants and generate the same code. Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* ext4: limit number of scanned extents in status tree shrinkerJan Kara2014-11-251-32/+59
| | | | | | | | | | | | | | | | | | | | | | 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>
* ext4: move handling of list of shrinkable inodes into extent status codeJan Kara2014-11-251-4/+6
| | | | | | | | | | | | | 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>
* ext4: change LRU to round-robin in extent status tree shrinkerZheng Liu2014-11-251-127/+97
| | | | | | | | | | | | | | | | 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>
* Merge tag 'ext4_for_linus' of ↵Linus Torvalds2014-10-201-18/+182
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4 Pull ext4 updates from Ted Ts'o: "A large number of cleanups and bug fixes, with some (minor) journal optimizations" [ This got sent to me before -rc1, but was stuck in my spam folder. - Linus ] * tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (67 commits) ext4: check s_chksum_driver when looking for bg csum presence ext4: move error report out of atomic context in ext4_init_block_bitmap() ext4: Replace open coded mdata csum feature to helper function ext4: delete useless comments about ext4_move_extents ext4: fix reservation overflow in ext4_da_write_begin ext4: add ext4_iget_normal() which is to be used for dir tree lookups ext4: don't orphan or truncate the boot loader inode ext4: grab missed write_count for EXT4_IOC_SWAP_BOOT ext4: optimize block allocation on grow indepth ext4: get rid of code duplication ext4: fix over-defensive complaint after journal abort ext4: fix return value of ext4_do_update_inode ext4: fix mmap data corruption when blocksize < pagesize vfs: fix data corruption when blocksize < pagesize for mmaped data ext4: fold ext4_nojournal_sops into ext4_sops ext4: support freezing ext2 (nojournal) file systems ext4: fold ext4_sync_fs_nojournal() into ext4_sync_fs() ext4: don't check quota format when there are no quota files jbd2: simplify calling convention around __jbd2_journal_clean_checkpoint_list jbd2: avoid pointless scanning of checkpoint lists ...
| * ext4: track extent status tree shrinker delay staticticsZheng Liu2014-09-021-10/+176
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This commit adds some statictics in extent status tree shrinker. The purpose to add these is that we want to collect more details when we encounter a stall caused by extent status tree shrinker. Here we count the following statictics: stats: the number of all objects on all extent status trees the number of reclaimable objects on lru list cache hits/misses the last sorted interval the number of inodes on lru list average: scan time for shrinking some objects the number of shrunk objects maximum: the inode that has max nr. of objects on lru list the maximum scan time for shrinking some objects The output looks like below: $ cat /proc/fs/ext4/sda1/es_shrinker_info stats: 28228 objects 6341 reclaimable objects 5281/631 cache hits/misses 586 ms last sorted interval 250 inodes on lru list average: 153 us scan time 128 shrunk objects maximum: 255 inode (255 objects, 198 reclaimable) 125723 us max scan time If the lru list has never been sorted, the following line will not be printed: 586ms last sorted interval If there is an empty lru list, the following lines also will not be printed: 250 inodes on lru list ... maximum: 255 inode (255 objects, 198 reclaimable) 0 us max scan time Meanwhile in this commit a new trace point is defined to print some details in __ext4_es_shrink(). Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: Jan Kara <jack@suse.cz> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Zheng Liu <wenqing.lz@taobao.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
| * ext4: improve extents status tree trace pointZheng Liu2014-09-021-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This commit improves the trace point of extents status tree. We rename trace_ext4_es_shrink_enter in ext4_es_count() because it is also used in ext4_es_scan() and we can not identify them from the result. Further this commit fixes a variable name in trace point in order to keep consistency with others. Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: Jan Kara <jack@suse.cz> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Zheng Liu <wenqing.lz@taobao.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
| * ext4: rename ext4_ext_find_extent() to ext4_find_extent()Theodore Ts'o2014-09-011-1/+1
| | | | | | | | | | | | Make the function name less redundant. Signed-off-by: Theodore Ts'o <tytso@mit.edu>
| * ext4: allow a NULL argument to ext4_ext_drop_refs()Theodore Ts'o2014-09-011-4/+2
|/ | | | | | | | Teach ext4_ext_drop_refs() to accept a NULL argument, much like kfree(). This allows us to drop a lot of checks to make sure path is non-NULL before calling ext4_ext_drop_refs(). Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* ext4: fix a potential deadlock in __ext4_es_shrink()Theodore Ts'o2014-07-121-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This fixes the following lockdep complaint: [ INFO: possible circular locking dependency detected ] 3.16.0-rc2-mm1+ #7 Tainted: G O ------------------------------------------------------- kworker/u24:0/4356 is trying to acquire lock: (&(&sbi->s_es_lru_lock)->rlock){+.+.-.}, at: [<ffffffff81285fff>] __ext4_es_shrink+0x4f/0x2e0 but task is already holding lock: (&ei->i_es_lock){++++-.}, at: [<ffffffff81286961>] ext4_es_insert_extent+0x71/0x180 which lock already depends on the new lock. Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&ei->i_es_lock); lock(&(&sbi->s_es_lru_lock)->rlock); lock(&ei->i_es_lock); lock(&(&sbi->s_es_lru_lock)->rlock); *** DEADLOCK *** 6 locks held by kworker/u24:0/4356: #0: ("writeback"){.+.+.+}, at: [<ffffffff81071d00>] process_one_work+0x180/0x560 #1: ((&(&wb->dwork)->work)){+.+.+.}, at: [<ffffffff81071d00>] process_one_work+0x180/0x560 #2: (&type->s_umount_key#22){++++++}, at: [<ffffffff811a9c74>] grab_super_passive+0x44/0x90 #3: (jbd2_handle){+.+...}, at: [<ffffffff812979f9>] start_this_handle+0x189/0x5f0 #4: (&ei->i_data_sem){++++..}, at: [<ffffffff81247062>] ext4_map_blocks+0x132/0x550 #5: (&ei->i_es_lock){++++-.}, at: [<ffffffff81286961>] ext4_es_insert_extent+0x71/0x180 stack backtrace: CPU: 0 PID: 4356 Comm: kworker/u24:0 Tainted: G O 3.16.0-rc2-mm1+ #7 Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 Workqueue: writeback bdi_writeback_workfn (flush-253:0) ffffffff8213dce0 ffff880014b07538 ffffffff815df0bb 0000000000000007 ffffffff8213e040 ffff880014b07588 ffffffff815db3dd ffff880014b07568 ffff880014b07610 ffff88003b868930 ffff88003b868908 ffff88003b868930 Call Trace: [<ffffffff815df0bb>] dump_stack+0x4e/0x68 [<ffffffff815db3dd>] print_circular_bug+0x1fb/0x20c [<ffffffff810a7a3e>] __lock_acquire+0x163e/0x1d00 [<ffffffff815e89dc>] ? retint_restore_args+0xe/0xe [<ffffffff815ddc7b>] ? __slab_alloc+0x4a8/0x4ce [<ffffffff81285fff>] ? __ext4_es_shrink+0x4f/0x2e0 [<ffffffff810a8707>] lock_acquire+0x87/0x120 [<ffffffff81285fff>] ? __ext4_es_shrink+0x4f/0x2e0 [<ffffffff8128592d>] ? ext4_es_free_extent+0x5d/0x70 [<ffffffff815e6f09>] _raw_spin_lock+0x39/0x50 [<ffffffff81285fff>] ? __ext4_es_shrink+0x4f/0x2e0 [<ffffffff8119760b>] ? kmem_cache_alloc+0x18b/0x1a0 [<ffffffff81285fff>] __ext4_es_shrink+0x4f/0x2e0 [<ffffffff812869b8>] ext4_es_insert_extent+0xc8/0x180 [<ffffffff812470f4>] ext4_map_blocks+0x1c4/0x550 [<ffffffff8124c4c4>] ext4_writepages+0x6d4/0xd00 ... Reported-by: Minchan Kim <minchan@kernel.org> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Reported-by: Minchan Kim <minchan@kernel.org> Cc: stable@vger.kernel.org Cc: Zheng Liu <gnehzuil.liu@gmail.com>
* ext4: use EXT_MAX_BLOCKS in ext4_es_can_be_merged()Lukas Czerner2014-05-131-1/+7
| | | | | | | | | | | | In ext4_es_can_be_merged() when checking whether we can merge two extents we should use EXT_MAX_BLOCKS instead of defining it manually. Also if it is really the case we should notify userspace because clearly there is a bug in extent status tree implementation since this should never happen. Signed-off-by: Lukas Czerner <lczerner@redhat.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Reviewed-by: Zheng Liu <wenqing.lz@taobao.com>
* ext4: rename uninitialized extents to unwrittenLukas Czerner2014-04-211-1/+1
| | | | | | | | | | | | | | | | | | | | | | | Currently in ext4 there is quite a mess when it comes to naming unwritten extents. Sometimes we call it uninitialized and sometimes we refer to it as unwritten. The right name for the extent which has been allocated but does not contain any written data is _unwritten_. Other file systems are using this name consistently, even the buffer head state refers to it as unwritten. We need to fix this confusion in ext4. This commit changes every reference to an uninitialized extent (meaning allocated but unwritten) to unwritten extent. This includes comments, function names and variable names. It even covers abbreviation of the word uninitialized (such as uninit) and some misspellings. This commit does not change any of the code paths at all. This has been confirmed by comparing md5sums of the assembly code of each object file after all the function names were stripped from it. Signed-off-by: Lukas Czerner <lczerner@redhat.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
* ext4: fix 64-bit number truncation warningChen Gang2014-04-071-1/+1
| | | | | | | | | | | | | | '0x7FDEADBEEF' will be truncated to 32-bit number under unicore32. Need append 'ULL' for it. The related warning (with allmodconfig under unicore32): CC [M] fs/ext4/extents_status.o fs/ext4/extents_status.c: In function "__es_remove_extent": fs/ext4/extents_status.c:813: warning: integer constant is too large for "long" type Signed-off-by: Chen Gang <gang.chen.5i5j@gmail.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
* ext4: silence warnings in extent status tree debugging codeEric Whitney2014-02-201-7/+7
| | | | | | | | | Adjust the conversion specifications in a few optionally compiled debug messages to match the return type of ext4_es_status(). Also, make a couple of minor grammatical message edits while we're at it. Signed-off-by: Eric Whitney <enwlinux@gmail.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
* ext4: add ext4_es_store_pblock_status()Theodore Ts'o2014-02-201-8/+6
| | | | | | | | | | | | | | Avoid false positives by static code analysis tools such as sparse and coverity caused by the fact that we set the physical block, and then the status in the extent_status structure. It is also more efficient to set both of these values at once. Addresses-Coverity-Id: #989077 Addresses-Coverity-Id: #989078 Addresses-Coverity-Id: #1080722 Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Reviewed-by: Zheng Liu <wenqing.lz@taobao.com>
* fs: convert fs shrinkers to new scan/count APIDave Chinner2013-09-111-9/+24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Convert the filesystem shrinkers to use the new API, and standardise some of the behaviours of the shrinkers at the same time. For example, nr_to_scan means the number of objects to scan, not the number of objects to free. I refactored the CIFS idmap shrinker a little - it really needs to be broken up into a shrinker per tree and keep an item count with the tree root so that we don't need to walk the tree every time the shrinker needs to count the number of objects in the tree (i.e. all the time under memory pressure). [glommer@openvz.org: fixes for ext4, ubifs, nfs, cifs and glock. Fixes are needed mainly due to new code merged in the tree] [assorted fixes folded in] Signed-off-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Glauber Costa <glommer@openvz.org> Acked-by: Mel Gorman <mgorman@suse.de> Acked-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com> Acked-by: Jan Kara <jack@suse.cz> Acked-by: Steven Whitehouse <swhiteho@redhat.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Artem Bityutskiy <artem.bityutskiy@linux.intel.com> Cc: Arve Hjønnevåg <arve@android.com> Cc: Carlos Maiolino <cmaiolino@redhat.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Chuck Lever <chuck.lever@oracle.com> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: David Rientjes <rientjes@google.com> Cc: Gleb Natapov <gleb@redhat.com> Cc: Greg Thelen <gthelen@google.com> Cc: J. Bruce Fields <bfields@redhat.com> Cc: Jan Kara <jack@suse.cz> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Stultz <john.stultz@linaro.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Kent Overstreet <koverstreet@google.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Thomas Hellstrom <thellstrom@vmware.com> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* ext4: isolate ext4_extents.h fileZheng Liu2013-08-281-18/+2
| | | | | | | | | | | | | | | | | | | After applied the commit (4a092d73), we have reduced the number of source files that need to #include ext4_extents.h. But we can do better. This commit defines ext4_zeroout_es() in extents.c and move EXT_MAX_BLOCKS into ext4.h in order not to include ext4_extents.h in indirect.c and ioctl.c. Meanwhile we just need to include this file in extent_status.c when ES_AGGRESSIVE_TEST is defined. Otherwise, this commit removes a duplicated declaration in trace/events/ext4.h. After applied this patch, we just need to include ext4_extents.h file in {super,migrate,move_extents,extents}.c, and it is easy for us to define a new extent disk layout. Signed-off-by: Zheng Liu <wenqing.lz@taobao.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
* ext4: add support for extent pre-cachingTheodore Ts'o2013-08-171-21/+51
| | | | | | | | | | | | | | | Add a new fiemap flag which forces the all of the extents in an inode to be cached in the extent_status tree. This is critically important when using AIO to a preallocated file, since if we need to read in blocks from the extent tree, the io_submit(2) system call becomes synchronous, and the AIO is no longer "A", which is bad. In addition, for most files which have an external leaf tree block, the cost of caching the information in the extent status tree will be less than caching the entire 4k block in the buffer cache. So it is generally a win to keep the extent information cached. Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
* ext4: cache all of an extent tree's leaf block upon readingTheodore Ts'o2013-08-171-1/+36
| | | | | | | | | | | When we read in an extent tree leaf block from disk, arrange to have all of its entries cached. In nearly all cases the in-memory representation will be more compact than the on-disk representation in the buffer cache, and it allows us to get the information without having to traverse the extent tree for successive extents. Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Reviewed-by: Zheng Liu <wenqing.lz@taobao.com>
* ext4: use unsigned int for es_status valuesTheodore Ts'o2013-08-171-3/+3
| | | | | | | | | | | Don't use an unsigned long long for the es_status flags; this requires that we pass 64-bit values around which is painful on 32-bit systems. Instead pass the extent status flags around using the low 4 bits of an unsigned int, and shift them into place when we are reading or writing es_pblk. Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Reviewed-by: Zheng Liu <wenqing.lz@taobao.com>
* ext4: make the extent_status code more robust against ENOMEM failuresTheodore Ts'o2013-07-151-12/+39
| | | | | | | | | | | | | | | | | Some callers of ext4_es_remove_extent() and ext4_es_insert_extent() may not be completely robust against ENOMEM failures (or the consequences of reflecting ENOMEM back up to userspace may lead to xfstest or user application failure). To mitigate against this, when trying to insert an entry in the extent status tree, try to shrink the inode's extent status tree before returning ENOMEM. If there are entries which don't record information about extents under delayed allocations, freeing one of them is preferable to returning ENOMEM. Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Reviewed-by: Zheng Liu <wenqing.lz@taobao.com>
* ext4: fix spelling errors and a comment in extent_status treeTheodore Ts'o2013-07-131-12/+10
| | | | | | | | | | | Replace "assertation" with "assertion" in lots and lots of debugging messages. Correct the comment stating when ext4_es_insert_extent() is used. It was no doubt tree at one point, but it is no longer true... Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Cc: Zheng Liu <gnehzuil.liu@gmail.com>