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Zheng Bin d0c7feaf87 xfs: add agf freeblocks verify in xfs_agf_verify
We recently used fuzz(hydra) to test XFS and automatically generate
tmp.img(XFS v5 format, but some metadata is wrong)

xfs_repair information(just one AG):
agf_freeblks 0, counted 3224 in ag 0
agf_longest 536874136, counted 3224 in ag 0
sb_fdblocks 613, counted 3228

Test as follows:
mount tmp.img tmpdir
cp file1M tmpdir
sync

In 4.19-stable, sync will stuck, the reason is:
xfs_mountfs
  xfs_check_summary_counts
    if ((!xfs_sb_version_haslazysbcount(&mp->m_sb) ||
       XFS_LAST_UNMOUNT_WAS_CLEAN(mp)) &&
       !xfs_fs_has_sickness(mp, XFS_SICK_FS_COUNTERS))
	return 0;  -->just return, incore sb_fdblocks still be 613
    xfs_initialize_perag_data

cp file1M tmpdir -->ok(write file to pagecache)
sync -->stuck(write pagecache to disk)
xfs_map_blocks
  xfs_iomap_write_allocate
    while (count_fsb != 0) {
      nimaps = 0;
      while (nimaps == 0) { --> endless loop
         nimaps = 1;
         xfs_bmapi_write(..., &nimaps) --> nimaps becomes 0 again
xfs_bmapi_write
  xfs_bmap_alloc
    xfs_bmap_btalloc
      xfs_alloc_vextent
        xfs_alloc_fix_freelist
          xfs_alloc_space_available -->fail(agf_freeblks is 0)

In linux-next, sync not stuck, cause commit c2b3164320 ("xfs:
use the latest extent at writeback delalloc conversion time") remove
the above while, dmesg is as follows:
[   55.250114] XFS (loop0): page discard on page ffffea0008bc7380, inode 0x1b0c, offset 0.

Users do not know why this page is discard, the better soultion is:
1. Like xfs_repair, make sure sb_fdblocks is equal to counted
(xfs_initialize_perag_data did this, who is not called at this mount)
2. Add agf verify, if fail, will tell users to repair

This patch use the second soultion.

Signed-off-by: Zheng Bin <zhengbin13@huawei.com>
Signed-off-by: Ren Xudong <renxudong1@huawei.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
History 2020-03-02 20:55:50 -08:00
arch More bugfixes, including a few remaining "make W=1" issues such 2020-03-01 15:16:35 -06:00
block blk-mq: Remove some unused function arguments 2020-02-26 10:34:41 -07:00
certs certs: Add wrapper function to check blacklisted binary hash 2019-11-12 12:25:50 +11:00
crypto Merge branch 'next-integrity' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity 2020-02-20 15:15:16 -08:00
Documentation ACPI fixes for 5.6-rc4 2020-02-28 09:02:18 -08:00
drivers Merge branch 'i2c/for-current-fixed' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux 2020-02-29 19:16:46 -06:00
fs xfs: add agf freeblocks verify in xfs_agf_verify 2020-03-02 20:55:50 -08:00
include More bugfixes, including a few remaining "make W=1" issues such 2020-03-01 15:16:35 -06:00
init Tracing updates: 2020-02-26 10:34:42 -08:00
ipc Revert "ipc,sem: remove uneeded sem_undo_list lock usage in exit_sem()" 2020-02-21 11:22:15 -08:00
kernel block-5.6-2020-02-28 2020-02-28 11:43:30 -08:00
lib Tracing updates: 2020-02-26 10:34:42 -08:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
mm Merge branch 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-02-24 11:32:15 -08:00
net vsock: fix potential deadlock in transport->release() 2020-02-27 12:03:56 -08:00
samples Kbuild updates for v5.6 (2nd) 2020-02-09 16:05:50 -08:00
scripts kbuild: remove unneeded semicolon at the end of cmd_dtb_check 2020-02-27 02:24:34 +09:00
security Merge branch 'next-integrity' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity 2020-02-20 15:15:16 -08:00
sound ASoC: Fixes for v5.6 2020-02-18 13:33:39 +01:00
tools Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-02-27 16:34:41 -08:00
usr Kbuild updates for v5.6 (2nd) 2020-02-09 16:05:50 -08:00
virt KVM/arm fixes for 5.6, take #1 2020-02-28 11:50:06 +01:00
.clang-format clang-format: Update with the latest for_each macro list 2019-08-31 10:00:51 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore selftest/lkdtm: Don't pollute 'git status' 2020-02-20 08:55:06 -07:00
.mailmap A handful of small documentation fixes that wandered in. 2020-02-07 13:03:10 -08:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Hand MIPS over to Thomas 2020-02-24 22:43:18 -08:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig docs: kbuild: convert docs to ReST and rename to *.rst 2019-06-14 14:21:21 -06:00
MAINTAINERS pci-v5.6-fixes-2 2020-02-28 11:51:53 -08:00
Makefile Linux 5.6-rc4 2020-03-01 16:38:46 -06:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.