From: Steven Whitehouse Date: Fri, 4 Oct 2013 11:29:34 +0000 (+0100) Subject: GFS2: Protect quota sync generation X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=e46c772dbafc2059b0c7ee87c6a7232baadaf6c7;p=linux.git GFS2: Protect quota sync generation Now that gfs2_quota_sync can be potentially called from multiple threads, we should protect this bit of code, and the sync generation number in particular in order to ensure that there are no races when syncing quotas. Signed-off-by: Steven Whitehouse Cc: Abhijith Das --- diff --git a/fs/gfs2/incore.h b/fs/gfs2/incore.h index 37b3cd795d6cf..2ab4f8d8f4c4b 100644 --- a/fs/gfs2/incore.h +++ b/fs/gfs2/incore.h @@ -714,6 +714,7 @@ struct gfs2_sbd { struct list_head sd_quota_list; atomic_t sd_quota_count; struct mutex sd_quota_mutex; + struct mutex sd_quota_sync_mutex; wait_queue_head_t sd_quota_wait; struct list_head sd_trunc_list; spinlock_t sd_trunc_lock; diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c index 8e40fda985d62..82303b4749582 100644 --- a/fs/gfs2/ops_fstype.c +++ b/fs/gfs2/ops_fstype.c @@ -93,6 +93,7 @@ static struct gfs2_sbd *init_sbd(struct super_block *sb) INIT_LIST_HEAD(&sdp->sd_quota_list); mutex_init(&sdp->sd_quota_mutex); + mutex_init(&sdp->sd_quota_sync_mutex); init_waitqueue_head(&sdp->sd_quota_wait); INIT_LIST_HEAD(&sdp->sd_trunc_list); spin_lock_init(&sdp->sd_trunc_lock); diff --git a/fs/gfs2/quota.c b/fs/gfs2/quota.c index cfb4cdeddacbd..4a9726aa191f5 100644 --- a/fs/gfs2/quota.c +++ b/fs/gfs2/quota.c @@ -1132,12 +1132,13 @@ int gfs2_quota_sync(struct super_block *sb, int type) unsigned int x; int error = 0; - sdp->sd_quota_sync_gen++; - qda = kcalloc(max_qd, sizeof(struct gfs2_quota_data *), GFP_KERNEL); if (!qda) return -ENOMEM; + mutex_lock(&sdp->sd_quota_sync_mutex); + sdp->sd_quota_sync_gen++; + do { num_qd = 0; @@ -1162,6 +1163,7 @@ int gfs2_quota_sync(struct super_block *sb, int type) } } while (!error && num_qd == max_qd); + mutex_unlock(&sdp->sd_quota_sync_mutex); kfree(qda); return error;