On Sun, Apr 30, 2017 at 04:04:39PM +0200, Greg Kroah-Hartman wrote: > > The patch below does not apply to the 4.4-stable tree. > If someone wants it applied there, or to any other stable or longterm > tree, then please email the backport, including the original git commit > id to <stable@xxxxxxxxxxxxxxx>. > Here's a backport I've tested with 4.4. Cheers, -- Luís >From beab414f9df0c865e73e651393538cde1fa20a3d Mon Sep 17 00:00:00 2001 From: "Yan, Zheng" <zyan@xxxxxxxxxx> Date: Wed, 19 Apr 2017 10:01:48 +0800 Subject: [PATCH] ceph: fix recursion between ceph_set_acl() and __ceph_setattr() commit 8179a101eb5f4ef0ac9a915fcea9a9d3109efa90 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. Cc: stable@xxxxxxxxxxxxxxx # needs backporting for < 4.9 Link: http://tracker.ceph.com/issues/19688 Reported-by: Jerry Lee <leisurelysw24@xxxxxxxxx> Signed-off-by: "Yan, Zheng" <zyan@xxxxxxxxxx> Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx> Tested-by: Luis Henriques <lhenriques@xxxxxxxx> Signed-off-by: Ilya Dryomov <idryomov@xxxxxxxxx> [luis: __ceph_setattr doesn't exist in 4.4, implement all the changes directly in ceph_setattr. The wrapper function was introduced only in commit a26feccaba29 ("ceph: Get rid of d_find_alias in ceph_set_acl").] Signed-off-by: Luis Henriques <lhenriques@xxxxxxxx> --- fs/ceph/inode.c | 18 +++++++----------- 1 file changed, 7 insertions(+), 11 deletions(-) diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c index d98536c8abfc..e3d19c3d246d 100644 --- a/fs/ceph/inode.c +++ b/fs/ceph/inode.c @@ -1975,11 +1975,6 @@ int ceph_setattr(struct dentry *dentry, struct iattr *attr) if (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) { req->r_inode = inode; @@ -1993,13 +1988,14 @@ int ceph_setattr(struct dentry *dentry, struct iattr *attr) ceph_cap_string(dirtied), mask); ceph_mdsc_put_request(req); - if (mask & CEPH_SETATTR_SIZE) - __ceph_do_pending_vmtruncate(inode); - ceph_free_cap_flush(prealloc_cf); - return err; -out_put: - ceph_mdsc_put_request(req); ceph_free_cap_flush(prealloc_cf); + + if (err >= 0 && (mask & CEPH_SETATTR_SIZE)) + __ceph_do_pending_vmtruncate(inode); + + if (err >= 0 && (attr->ia_valid & ATTR_MODE)) + err = posix_acl_chmod(inode, attr->ia_mode); + return err; }