3.18-stable review patch. If anyone has any objections, please let me know.
------------------
From: piaojun <piao...@huawei.com>
[ Upstream commit 16c8d569f5704a84164f30ff01b29879f3438065 ]
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.7030...@huawei.com
Signed-off-by: Jun Piao <piao...@huawei.com>
Reviewed-by: Alex Chen <alex.c...@huawei.com>
Cc: Mark Fasheh <mfas...@versity.com>
Cc: Joel Becker <jl...@evilplan.org>
Cc: Junxiao Bi <junxiao...@oracle.com>
Cc: Joseph Qi <jiangqi...@gmail.com>
Cc: Changwei Ge <ge.chang...@h3c.com>
Signed-off-by: Andrew Morton <a...@linux-foundation.org>
Signed-off-by: Linus Torvalds <torva...@linux-foundation.org>
Signed-off-by: Sasha Levin <alexander.le...@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
fs/ocfs2/acl.c | 6 ++++++
fs/ocfs2/xattr.c | 2 ++
2 files changed, 8 insertions(+)
--- a/fs/ocfs2/acl.c
+++ b/fs/ocfs2/acl.c
@@ -300,7 +300,9 @@ struct posix_acl *ocfs2_iop_get_acl(stru
if (ret < 0)
return ERR_PTR(ret);
+ down_read(&OCFS2_I(inode)->ip_xattr_sem);
acl = ocfs2_get_acl_nolock(inode, type, di_bh);
+ up_read(&OCFS2_I(inode)->ip_xattr_sem);
brelse(di_bh);
@@ -319,7 +321,9 @@ int ocfs2_acl_chmod(struct inode *inode,
if (!(osb->s_mount_opt & OCFS2_MOUNT_POSIX_ACL))
return 0;
+ down_read(&OCFS2_I(inode)->ip_xattr_sem);
acl = ocfs2_get_acl_nolock(inode, ACL_TYPE_ACCESS, bh);
+ up_read(&OCFS2_I(inode)->ip_xattr_sem);
if (IS_ERR(acl) || !acl)
return PTR_ERR(acl);
ret = __posix_acl_chmod(&acl, GFP_KERNEL, inode->i_mode);
@@ -350,8 +354,10 @@ int ocfs2_init_acl(handle_t *handle,
if (!S_ISLNK(inode->i_mode)) {
if (osb->s_mount_opt & OCFS2_MOUNT_POSIX_ACL) {
+ down_read(&OCFS2_I(dir)->ip_xattr_sem);
acl = ocfs2_get_acl_nolock(dir, ACL_TYPE_DEFAULT,
dir_bh);
+ up_read(&OCFS2_I(dir)->ip_xattr_sem);
if (IS_ERR(acl))
return PTR_ERR(acl);
}
--- a/fs/ocfs2/xattr.c
+++ b/fs/ocfs2/xattr.c
@@ -645,9 +645,11 @@ int ocfs2_calc_xattr_init(struct inode *
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))
