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 (8.14.3/8.14.3/SuSE Linux 0.8) with ESMTP id o39MTlFD146481 for ; Fri, 9 Apr 2010 17:29:47 -0500 Received: from cf--amer001e--3.americas.sgi.com (cf--amer001e--3.americas.sgi.com [137.38.100.5]) by relay1.corp.sgi.com (Postfix) with ESMTP id E7AE98F80D1 for ; Fri, 9 Apr 2010 15:31:39 -0700 (PDT) Subject: [PATCH 2/10] xfs: fix min bufsize bugs in two places From: Alex Elder Date: Fri, 09 Apr 2010 17:26:53 -0500 Message-ID: <1270852013.7840.132.camel@doink> Mime-Version: 1.0 Reply-To: aelder@sgi.com List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: xfs-bounces@oss.sgi.com Errors-To: xfs-bounces@oss.sgi.com To: xfs@oss.sgi.com This fixes a bug in two places that I found by inspection. In xlog_find_verify_cycle() and xlog_write_log_records(), the code attempts to allocate a buffer to hold as many blocks as possible. It gives up if the number of blocks to be allocated gets too small. Right now it uses log->l_sectbb_log as that lower bound, but I'm sure it's supposed to be the actual log sector size instead. That is, the lower bound should be (1 << log->l_sectbb_log). Also define a simple macro xlog_sectbb(log) to represent the number of basic blocks in a sector for the given log. (No change from original submission; I have implemented Christoph's suggestion about storing l_sectsize rather than l_sectbb_log in a new, separate patch in this series.) Signed-off-by: Alex Elder --- fs/xfs/xfs_log_recover.c | 21 +++++++++++++++++---- fs/xfs/xfs_log_recover.c | 21 +++++++++++++++++---- 1 file changed, 17 insertions(+), 4 deletions(-) Index: b/fs/xfs/xfs_log_recover.c =================================================================== --- a/fs/xfs/xfs_log_recover.c +++ b/fs/xfs/xfs_log_recover.c @@ -66,6 +66,9 @@ STATIC void xlog_recover_check_summary(x ((bbs + (log)->l_sectbb_mask + 1) & ~(log)->l_sectbb_mask) : (bbs) ) #define XLOG_SECTOR_ROUNDDOWN_BLKNO(log, bno) ((bno) & ~(log)->l_sectbb_mask) +/* Number of basic blocks in a log sector */ +#define xlog_sectbb(log) (1 << (log)->l_sectbb_log) + STATIC xfs_buf_t * xlog_get_bp( xlog_t *log, @@ -376,12 +379,16 @@ xlog_find_verify_cycle( xfs_caddr_t buf = NULL; int error = 0; + /* + * Greedily allocate a buffer big enough to handle the full + * range of basic blocks we'll be examining. If that fails, + * try a smaller size. We need to be able to read at least + * a log sector, or we're out of luck. + */ bufblks = 1 << ffs(nbblks); - while (!(bp = xlog_get_bp(log, bufblks))) { - /* can't get enough memory to do everything in one big buffer */ bufblks >>= 1; - if (bufblks <= log->l_sectbb_log) + if (bufblks < xlog_sectbb(log)) return ENOMEM; } @@ -1158,10 +1165,16 @@ xlog_write_log_records( int error = 0; int i, j = 0; + /* + * Greedily allocate a buffer big enough to handle the full + * range of basic blocks to be written. If that fails, try + * a smaller size. We need to be able to write at least a + * log sector, or we're out of luck. + */ bufblks = 1 << ffs(blocks); while (!(bp = xlog_get_bp(log, bufblks))) { bufblks >>= 1; - if (bufblks <= log->l_sectbb_log) + if (bufblks < xlog_sectbb(log)) return ENOMEM; } _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs