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Commit 8179a101 authored by Yan, Zheng's avatar Yan, Zheng Committed by Ilya Dryomov
Browse files

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

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@vger.kernel.org # needs backporting for < 4.9
Link: http://tracker.ceph.com/issues/19688


Reported-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>
parent 5a7ad114

fs/ceph/inode.c

+10 −12
Original line number Diff line number Diff line
@@ -2071,11 +2071,6 @@ 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;
@@ -2088,14 +2083,12 @@ int __ceph_setattr(struct inode *inode, struct iattr *attr) 
	dout("setattr %p result=%d (%s locally, %d remote)\n", inode, err,

	     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;

}
@@ -2114,7 +2107,12 @@ 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;

}



/*