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| author | piaojun <piaojun@huawei.com> | 2018-02-01 01:14:59 +0100 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2018-02-01 02:18:35 +0100 |
| commit | 16c8d569f5704a84164f30ff01b29879f3438065 (patch) | |
| tree | c775e1a2cdba767c6d66b054eccbcc131ad428c3 /fs/ocfs2/xattr.c | |
| parent | ocfs2: clean up dead code in alloc.c (diff) | |
| download | linux-16c8d569f5704a84164f30ff01b29879f3438065.tar.xz linux-16c8d569f5704a84164f30ff01b29879f3438065.zip | |
ocfs2/acl: use 'ip_xattr_sem' to protect getting extended attribute
The race between *set_acl and *get_acl will cause getting incomplete
xattr data as below:
processA processB
ocfs2_set_acl
ocfs2_xattr_set
__ocfs2_xattr_set_handle
ocfs2_get_acl_nolock
ocfs2_xattr_get_nolock:
processB may get incomplete xattr data if processA hasn't set_acl done.
So we should use 'ip_xattr_sem' to protect getting extended attribute in
ocfs2_get_acl_nolock(), as other processes could be changing it
concurrently.
Link: http://lkml.kernel.org/r/5A5DDCFF.7030001@huawei.com
Signed-off-by: Jun Piao <piaojun@huawei.com>
Reviewed-by: Alex Chen <alex.chen@huawei.com>
Cc: Mark Fasheh <mfasheh@versity.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Joseph Qi <jiangqi903@gmail.com>
Cc: Changwei Ge <ge.changwei@h3c.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/ocfs2/xattr.c')
| -rw-r--r-- | fs/ocfs2/xattr.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/fs/ocfs2/xattr.c b/fs/ocfs2/xattr.c index 268619c96b4e..c261c1dfd374 100644 --- a/fs/ocfs2/xattr.c +++ b/fs/ocfs2/xattr.c @@ -638,9 +638,11 @@ int ocfs2_calc_xattr_init(struct inode *dir, si->value_len); if (osb->s_mount_opt & OCFS2_MOUNT_POSIX_ACL) { + down_read(&OCFS2_I(dir)->ip_xattr_sem); acl_len = ocfs2_xattr_get_nolock(dir, dir_bh, OCFS2_XATTR_INDEX_POSIX_ACL_DEFAULT, "", NULL, 0); + up_read(&OCFS2_I(dir)->ip_xattr_sem); if (acl_len > 0) { a_size = ocfs2_xattr_entry_real_size(0, acl_len); if (S_ISDIR(mode)) |