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| author | Konstantin Khlebnikov <khlebnikov@yandex-team.ru> | 2020-04-09 11:29:47 +0300 |
|---|---|---|
| committer | Miklos Szeredi <mszeredi@redhat.com> | 2020-05-13 11:11:24 +0200 |
| commit | 32b1924b210a70dcacdf65abd687c5ef86a67541 (patch) | |
| tree | 19372bfcaac553c2f8dd787e13fd0a8f23039cb2 /fs/sync.c | |
| parent | 62a8a85be8355b01330667c2b4676fb60c184380 (diff) | |
| download | lwn-32b1924b210a70dcacdf65abd687c5ef86a67541.tar.gz lwn-32b1924b210a70dcacdf65abd687c5ef86a67541.zip | |
ovl: skip overlayfs superblocks at global sync
Stacked filesystems like overlayfs has no own writeback, but they have to
forward syncfs() requests to backend for keeping data integrity.
During global sync() each overlayfs instance calls method ->sync_fs() for
backend although it itself is in global list of superblocks too. As a
result one syscall sync() could write one superblock several times and send
multiple disk barriers.
This patch adds flag SB_I_SKIP_SYNC into sb->sb_iflags to avoid that.
Reported-by: Dmitry Monakhov <dmtrmonakhov@yandex-team.ru>
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Diffstat (limited to 'fs/sync.c')
| -rw-r--r-- | fs/sync.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/fs/sync.c b/fs/sync.c index 4d1ff010bc5a..16c2630ee4bf 100644 --- a/fs/sync.c +++ b/fs/sync.c @@ -76,7 +76,8 @@ static void sync_inodes_one_sb(struct super_block *sb, void *arg) static void sync_fs_one_sb(struct super_block *sb, void *arg) { - if (!sb_rdonly(sb) && sb->s_op->sync_fs) + if (!sb_rdonly(sb) && !(sb->s_iflags & SB_I_SKIP_SYNC) && + sb->s_op->sync_fs) sb->s_op->sync_fs(sb, *(int *)arg); } |