commit | 2c152aa3294204d893708aac1a15c9da2957b553 | [log] [tgz] |
---|---|---|
author | Yangtao Li <frank.li@vivo.com> | Wed Aug 04 11:29:46 2021 +0800 |
committer | Todd Kjos <tkjos@google.com> | Fri Jan 14 17:35:16 2022 +0000 |
tree | 4787869c50f861530627c50a81837bd55d1e351d | |
parent | c29dd368efc6830924dd5f894fd96851c1ceae51 [diff] |
UPSTREAM: f2fs: reduce the scope of setting fsck tag when de->name_len is zero I recently found a case where de->name_len is 0 in f2fs_fill_dentries() easily reproduced, and finally set the fsck flag. Thread A Thread B - f2fs_readdir - f2fs_read_inline_dir - ctx->pos = d.max - f2fs_add_dentry - f2fs_add_inline_entry - do_convert_inline_dir - f2fs_add_regular_entry - f2fs_readdir - f2fs_fill_dentries - set_sbi_flag(sbi, SBI_NEED_FSCK) Process A opens the folder, and has been reading without closing it. During this period, Process B created a file under the folder (occupying multiple f2fs_dir_entry, exceeding the d.max of the inline dir). After creation, process A uses the d.max of inline dir to read it again, and it will read that de->name_len is 0. And Chao pointed out that w/o inline conversion, the race condition still can happen as below: dir_entry1: A dir_entry2: B dir_entry3: C free slot: _ ctx->pos: ^ Thread A is traversing directory, ctx-pos moves to below position after readdir() by thread A: AAAABBBB___ ^ Then thread B delete dir_entry2, and create dir_entry3. Thread A calls readdir() to lookup dirents starting from middle of new dirent slots as below: AAAACCCCCC_ ^ In these scenarios, the file system is not damaged, and it's hard to avoid it. But we can bypass tagging FSCK flag if: a) bit_pos (:= ctx->pos % d->max) is non-zero and b) before bit_pos moves to first valid dir_entry. Fixes: ddf06b753a85 ("f2fs: fix to trigger fsck if dirent.name_len is zero") Signed-off-by: Yangtao Li <frank.li@vivo.com> [Chao: clean up description] Reviewed-by: Chao Yu <chao@kernel.org> (cherry picked from commit 7b9b92ff1bf07300628e05d966d28318f32b3ecc) Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org> Change-Id: Iffb4f0e92a6c98cfafb9dcc7d7a0f5e5b1b3a1ef Change-Id: Ic7bd8a5bb10f2770fee913f4b5faad4f2b177efb Signed-off-by: haojianhua1 <haojianhua1@xiaomi.com>
BEST: Make all of your changes to upstream Linux. If appropriate, backport to the stable releases. These patches will be merged automatically in the corresponding common kernels. If the patch is already in upstream Linux, post a backport of the patch that conforms to the patch requirements below.
EXPORT_SYMBOL_GPL()
require an in-tree modular driver that uses the symbol -- so include the new driver or changes to an existing driver in the same patchset as the export.LESS GOOD: Develop your patches out-of-tree (from an upstream Linux point-of-view). Unless these are fixing an Android-specific bug, these are very unlikely to be accepted unless they have been coordinated with kernel-team@android.com. If you want to proceed, post a patch that conforms to the patch requirements below.
script/checkpatch.pl
UPSTREAM:
, BACKPORT:
, FROMGIT:
, FROMLIST:
, or ANDROID:
.Change-Id:
tag (see https://gerrit-review.googlesource.com/Documentation/user-changeid.html)Bug:
tag.Signed-off-by:
tag by the author and the submitterAdditional requirements are listed below based on patch type
UPSTREAM:
, BACKPORT:
UPSTREAM:
.(cherry picked from commit ...)
lineimportant patch from upstream This is the detailed description of the important patch Signed-off-by: Fred Jones <fred.jones@foo.org>
- then Joe Smith would upload the patch for the common kernel as
UPSTREAM: important patch from upstream This is the detailed description of the important patch Signed-off-by: Fred Jones <fred.jones@foo.org> Bug: 135791357 Change-Id: I4caaaa566ea080fa148c5e768bb1a0b6f7201c01 (cherry picked from commit c31e73121f4c1ec41143423ac6ce3ce6dafdcec1) Signed-off-by: Joe Smith <joe.smith@foo.org>
BACKPORT:
instead of UPSTREAM:
.UPSTREAM:
(cherry picked from commit ...)
lineBACKPORT: important patch from upstream This is the detailed description of the important patch Signed-off-by: Fred Jones <fred.jones@foo.org> Bug: 135791357 Change-Id: I4caaaa566ea080fa148c5e768bb1a0b6f7201c01 (cherry picked from commit c31e73121f4c1ec41143423ac6ce3ce6dafdcec1) [joe: Resolved minor conflict in drivers/foo/bar.c ] Signed-off-by: Joe Smith <joe.smith@foo.org>
FROMGIT:
, FROMLIST:
,FROMGIT:
(cherry picked from commit <sha1> <repo> <branch>)
. This must be a stable maintainer branch (not rebased, so don't use linux-next
for example).BACKPORT: FROMGIT:
important patch from upstream This is the detailed description of the important patch Signed-off-by: Fred Jones <fred.jones@foo.org>
- then Joe Smith would upload the patch for the common kernel as
FROMGIT: important patch from upstream This is the detailed description of the important patch Signed-off-by: Fred Jones <fred.jones@foo.org> Bug: 135791357 (cherry picked from commit 878a2fd9de10b03d11d2f622250285c7e63deace https://git.kernel.org/pub/scm/linux/kernel/git/foo/bar.git test-branch) Change-Id: I4caaaa566ea080fa148c5e768bb1a0b6f7201c01 Signed-off-by: Joe Smith <joe.smith@foo.org>
FROMLIST:
Link:
tag with a link to the submittal on lore.kernel.orgBug:
tag with the Android bug (required for patches not accepted into a maintainer tree)BACKPORT: FROMLIST:
FROMLIST: important patch from upstream This is the detailed description of the important patch Signed-off-by: Fred Jones <fred.jones@foo.org> Bug: 135791357 Link: https://lore.kernel.org/lkml/20190619171517.GA17557@someone.com/ Change-Id: I4caaaa566ea080fa148c5e768bb1a0b6f7201c01 Signed-off-by: Joe Smith <joe.smith@foo.org>
ANDROID:
ANDROID:
Fixes:
tag that cites the patch with the bugANDROID: fix android-specific bug in foobar.c This is the detailed description of the important fix Fixes: 1234abcd2468 ("foobar: add cool feature") Change-Id: I4caaaa566ea080fa148c5e768bb1a0b6f7201c01 Signed-off-by: Joe Smith <joe.smith@foo.org>
ANDROID:
Bug:
tag with the Android bug (required for android-specific features)