Commit 51bd778a authored by Yan, Zheng's avatar Yan, Zheng Committed by Ben Hutchings

ceph: fix recursion between ceph_set_acl() and __ceph_setattr()

commit 8179a101 upstream.

ceph_set_acl() calls __ceph_setattr() if the setacl operation needs
to modify inode's i_mode. __ceph_setattr() updates inode's i_mode,
then calls posix_acl_chmod().

The problem is that __ceph_setattr() calls posix_acl_chmod() before
sending the setattr request. The get_acl() call in posix_acl_chmod()
can trigger a getxattr request. The reply of the getxattr request
can restore inode's i_mode to its old value. The set_acl() call in
posix_acl_chmod() sees old value of inode's i_mode, so it calls
__ceph_setattr() again.

Link: http://tracker.ceph.com/issues/19688Reported-by: default avatarJerry Lee <leisurelysw24@gmail.com>
Signed-off-by: default avatar"Yan, Zheng" <zyan@redhat.com>
Reviewed-by: default avatarJeff Layton <jlayton@redhat.com>
Tested-by: default avatarLuis Henriques <lhenriques@suse.com>
Signed-off-by: default avatarIlya Dryomov <idryomov@gmail.com>
[bwh: Backported to 3.16: All the changes are made in ceph_setattr() as
 there is no __ceph_setattr() function.]
Signed-off-by: default avatarBen Hutchings <ben@decadent.org.uk>
parent eacf8070
...@@ -1875,12 +1875,6 @@ int ceph_setattr(struct dentry *dentry, struct iattr *attr) ...@@ -1875,12 +1875,6 @@ int ceph_setattr(struct dentry *dentry, struct iattr *attr)
if (inode_dirty_flags) if (inode_dirty_flags)
__mark_inode_dirty(inode, inode_dirty_flags); __mark_inode_dirty(inode, inode_dirty_flags);
if (ia_valid & ATTR_MODE) {
err = posix_acl_chmod(inode, attr->ia_mode);
if (err)
goto out_put;
}
if (mask) { if (mask) {
req->r_inode = inode; req->r_inode = inode;
ihold(inode); ihold(inode);
...@@ -1893,12 +1887,16 @@ int ceph_setattr(struct dentry *dentry, struct iattr *attr) ...@@ -1893,12 +1887,16 @@ int ceph_setattr(struct dentry *dentry, struct iattr *attr)
ceph_cap_string(dirtied), mask); ceph_cap_string(dirtied), mask);
ceph_mdsc_put_request(req); ceph_mdsc_put_request(req);
if (mask & CEPH_SETATTR_SIZE)
if (err >= 0 && (mask & CEPH_SETATTR_SIZE))
__ceph_do_pending_vmtruncate(inode); __ceph_do_pending_vmtruncate(inode);
if (err >= 0 && (attr->ia_valid & ATTR_MODE))
err = posix_acl_chmod(inode, attr->ia_mode);
return err; return err;
out: out:
spin_unlock(&ci->i_ceph_lock); spin_unlock(&ci->i_ceph_lock);
out_put:
ceph_mdsc_put_request(req); ceph_mdsc_put_request(req);
return err; return err;
} }
......
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