From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from relay.sgi.com (relay1.corp.sgi.com [137.38.102.111]) by oss.sgi.com (Postfix) with ESMTP id 37F7029DFA for ; Sun, 21 Apr 2013 12:54:44 -0500 (CDT) Received: from eagdhcp-232-136.americas.sgi.com (eagdhcp-232-136.americas.sgi.com [128.162.232.136]) by relay1.corp.sgi.com (Postfix) with ESMTP id 2037D8F804C for ; Sun, 21 Apr 2013 10:54:41 -0700 (PDT) Received: from eagdhcp-232-136.americas.sgi.com (localhost [127.0.0.1]) by eagdhcp-232-136.americas.sgi.com (8.14.5/8.14.5) with ESMTP id r3LHsjSk002092 for ; Sun, 21 Apr 2013 12:54:45 -0500 (CDT) (envelope-from tinguely@sgi.com) Message-Id: <20130421174107.007313126@sgi.com> Date: Sun, 21 Apr 2013 12:41:03 -0500 From: Mark Tinguely Subject: [PATCH] xfs: shutdown filesystem if xfs_perag_get fails References: <20130419204102.736961610@sgi.com> Content-Disposition: inline; filename=xfs_force_shutdown_if_pag_is_NULL.patch List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: xfs-bounces@oss.sgi.com Sender: xfs-bounces@oss.sgi.com To: xfs@oss.sgi.com This problem happened locally with a bad inode number from xfs recovery. xfs_perag_get() can return NULL if given a bad agno. Most callers of xfs_perag_get() do not check for a NULL before using the pointer. This patch forces a shutdown of the filesystem for those callers that do not check the return value rather than crashing on a dereferenced NULL pointer. Signed-off-by: Mark Tinguely --- fs/xfs/xfs_icache.c | 2 +- fs/xfs/xfs_mount.c | 4 ++-- fs/xfs/xfs_mount.h | 17 ++++++++++++++++- 3 files changed, 19 insertions(+), 4 deletions(-) Index: b/fs/xfs/xfs_icache.c =================================================================== --- a/fs/xfs/xfs_icache.c +++ b/fs/xfs/xfs_icache.c @@ -656,7 +656,7 @@ xfs_inode_ag_iterator( xfs_agnumber_t ag; ag = 0; - while ((pag = xfs_perag_get(mp, ag))) { + while ((pag = __xfs_perag_get(mp, ag))) { ag = pag->pag_agno + 1; error = xfs_inode_ag_walk(mp, pag, execute, flags, args, -1); xfs_perag_put(pag); Index: b/fs/xfs/xfs_mount.c =================================================================== --- a/fs/xfs/xfs_mount.c +++ b/fs/xfs/xfs_mount.c @@ -193,7 +193,7 @@ xfs_uuid_unmount( * have to protect against changes is the tree structure itself. */ struct xfs_perag * -xfs_perag_get(struct xfs_mount *mp, xfs_agnumber_t agno) +__xfs_perag_get(struct xfs_mount *mp, xfs_agnumber_t agno) { struct xfs_perag *pag; int ref = 0; @@ -442,7 +442,7 @@ xfs_initialize_perag( * AGs we don't find ready for initialisation. */ for (index = 0; index < agcount; index++) { - pag = xfs_perag_get(mp, index); + pag = __xfs_perag_get(mp, index); if (pag) { xfs_perag_put(pag); continue; Index: b/fs/xfs/xfs_mount.h =================================================================== --- a/fs/xfs/xfs_mount.h +++ b/fs/xfs/xfs_mount.h @@ -336,12 +336,27 @@ xfs_daddr_to_agbno(struct xfs_mount *mp, /* * perag get/put wrappers for ref counting */ -struct xfs_perag *xfs_perag_get(struct xfs_mount *mp, xfs_agnumber_t agno); +struct xfs_perag *__xfs_perag_get(struct xfs_mount *mp, xfs_agnumber_t agno); struct xfs_perag *xfs_perag_get_tag(struct xfs_mount *mp, xfs_agnumber_t agno, int tag); void xfs_perag_put(struct xfs_perag *pag); /* + * Ensure the per AG entry was found. Shutting down the filesystem + * is better than crashing the OS. + */ +static inline struct xfs_perag * +xfs_perag_get(struct xfs_mount *mp, xfs_agnumber_t agno) +{ + struct xfs_perag *pag; + + pag = __xfs_perag_get(mp, agno); + if (!pag) + xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_INCORE); + return pag; +} + +/* * Per-cpu superblock locking functions */ #ifdef HAVE_PERCPU_SB _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs