This is a note to let you know that I've just added the patch titled
ceph: fix recursion between ceph_set_acl() and __ceph_setattr()
to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
ceph-fix-recursion-between-ceph_set_acl-and-__ceph_setattr.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 8179a101eb5f4ef0ac9a915fcea9a9d3109efa90 Mon Sep 17 00:00:00 2001
From: "Yan, Zheng" <zyan@xxxxxxxxxx>
Date: Wed, 19 Apr 2017 10:01:48 +0800
Subject: ceph: fix recursion between ceph_set_acl() and __ceph_setattr()
From: Yan, Zheng <zyan@xxxxxxxxxx>
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.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/ceph/inode.c | 22 ++++++++++------------
1 file changed, 10 insertions(+), 12 deletions(-)
--- a/fs/ceph/inode.c
+++ b/fs/ceph/inode.c
@@ -2080,11 +2080,6 @@ int __ceph_setattr(struct inode *inode,
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;
@@ -2098,13 +2093,11 @@ int __ceph_setattr(struct inode *inode,
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);
+
return err;
}
@@ -2123,7 +2116,12 @@ int ceph_setattr(struct dentry *dentry,
if (err != 0)
return err;
- return __ceph_setattr(inode, attr);
+ err = __ceph_setattr(inode, attr);
+
+ if (err >= 0 && (attr->ia_valid & ATTR_MODE))
+ err = posix_acl_chmod(inode, attr->ia_mode);
+
+ return err;
}
/*
Patches currently in stable-queue which might be from zyan@xxxxxxxxxx are
queue-4.9/ceph-fix-recursion-between-ceph_set_acl-and-__ceph_setattr.patch