From 3942ae5319640ced5844b75f44884e4bcb8a2f16 Mon Sep 17 00:00:00 2001 From: Steven Whitehouse Date: Mon, 11 Jul 2011 08:53:30 +0100 Subject: GFS2: Fix race during filesystem mount There is a potential race during filesystem mounting which has recently been reported. It occurs when the userland gfs_controld is able to process requests fast enough that it tries to use the sysfs interface before the lock module is properly initialised. This is a pretty unusual case as normally the lock module initialisation is very quick compared with gfs_controld. This patch adds an interruptible completion which is used to ensure that userland will wait for the initialisation of the lock module to complete. There are other potential solutions to this problem, but this is the quickest at this stage and has been tested both with and without mount.gfs2 present in the system. Signed-off-by: Steven Whitehouse Reported-by: David Booher --- fs/gfs2/sys.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) (limited to 'fs/gfs2/sys.c') diff --git a/fs/gfs2/sys.c b/fs/gfs2/sys.c index e20eab37bc8..443cabcfcd2 100644 --- a/fs/gfs2/sys.c +++ b/fs/gfs2/sys.c @@ -338,6 +338,9 @@ static ssize_t lkfirst_store(struct gfs2_sbd *sdp, const char *buf, size_t len) rv = sscanf(buf, "%u", &first); if (rv != 1 || first > 1) return -EINVAL; + rv = wait_for_completion_killable(&sdp->sd_locking_init); + if (rv) + return rv; spin_lock(&sdp->sd_jindex_spin); rv = -EBUSY; if (test_bit(SDF_NOJOURNALID, &sdp->sd_flags) == 0) @@ -414,7 +417,9 @@ static ssize_t jid_store(struct gfs2_sbd *sdp, const char *buf, size_t len) rv = sscanf(buf, "%d", &jid); if (rv != 1) return -EINVAL; - + rv = wait_for_completion_killable(&sdp->sd_locking_init); + if (rv) + return rv; spin_lock(&sdp->sd_jindex_spin); rv = -EINVAL; if (sdp->sd_lockstruct.ls_ops->lm_mount == NULL) -- cgit v1.2.3-70-g09d2