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

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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@gmail.com>
Signed-off-by: "Yan, Zheng" <zyan@redhat.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Tested-by: Luis Henriques <lhenriques@suse.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Yan, Zheng 2017-04-19 10:01:48 +08:00 committed by Greg Kroah-Hartman
parent d7809b9e99
commit 36e0be3187
1 changed files with 10 additions and 12 deletions
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22
fs/ceph/inode.c
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@ -2080,11 +2080,6 @@ int __ceph_setattr(struct inode *inode, 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;
@ -2098,13 +2093,11 @@ int __ceph_setattr(struct inode *inode, struct iattr *attr)
ceph_cap_string(dirtied), mask);
ceph_mdsc_put_request(req);
if (mask & CEPH_SETATTR_SIZE)
ceph_free_cap_flush(prealloc_cf);
if (err >= 0 && (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);
return err;
}
@ -2123,7 +2116,12 @@ int ceph_setattr(struct dentry *dentry, struct iattr *attr)
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;
}
/*