From 484adff8a06cb5d952832f5487ae863f54c0fb69 Mon Sep 17 00:00:00 2001 From: Steven Whitehouse Date: Wed, 29 Mar 2006 09:12:12 -0500 Subject: [GFS2] Update locking in log.c Replace the lock_for_trans()/lock_for_flush() functions with an rwsem. In fact the sd_log_flush_lock becomes an rwsem (the write part of it) and is extended slightly to cover everything that the lock_for_flush() used to cover. The read part of the lock is instead of lock_for_trans(). This corrects the races in the original code and reduces the code size. Signed-off-by: Steven Whitehouse --- fs/gfs2/log.c | 67 ++++++++++++++++------------------------------------------- 1 file changed, 18 insertions(+), 49 deletions(-) (limited to 'fs/gfs2/log.c') diff --git a/fs/gfs2/log.c b/fs/gfs2/log.c index 16c14441a37..b103d9acf40 100644 --- a/fs/gfs2/log.c +++ b/fs/gfs2/log.c @@ -29,32 +29,6 @@ #define PULL 1 -static void lock_for_trans(struct gfs2_sbd *sdp) -{ - wait_event(sdp->sd_log_trans_wq, atomic_read(&sdp->sd_log_flush_count) ? 0 : 1); - atomic_inc(&sdp->sd_log_trans_count); -} - -static void unlock_from_trans(struct gfs2_sbd *sdp) -{ - gfs2_assert_warn(sdp, atomic_read(&sdp->sd_log_trans_count)); - if (atomic_dec_and_test(&sdp->sd_log_trans_count)) - wake_up(&sdp->sd_log_flush_wq); -} - -static void gfs2_lock_for_flush(struct gfs2_sbd *sdp) -{ - atomic_inc(&sdp->sd_log_flush_count); - wait_event(sdp->sd_log_flush_wq, atomic_read(&sdp->sd_log_trans_count) ? 0 : 1); -} - -static void gfs2_unlock_from_flush(struct gfs2_sbd *sdp) -{ - gfs2_assert_warn(sdp, atomic_read(&sdp->sd_log_flush_count)); - if (atomic_dec_and_test(&sdp->sd_log_flush_count)) - wake_up(&sdp->sd_log_trans_wq); -} - /** * gfs2_struct2blk - compute stuff * @sdp: the filesystem @@ -109,9 +83,8 @@ void gfs2_ail1_start(struct gfs2_sbd *sdp, int flags) first = NULL; for (;;) { - if (first && - (head->prev != first || - gfs2_ail1_empty_one(sdp, first_ai, 0))) + if (first && (head->prev != first || + gfs2_ail1_empty_one(sdp, first_ai, 0))) break; for (tmp = head->prev; tmp != head; tmp = tmp->prev) { @@ -194,23 +167,21 @@ int gfs2_log_reserve(struct gfs2_sbd *sdp, unsigned int blks) return -EINVAL; mutex_lock(&sdp->sd_log_reserve_mutex); - for (;;) { - gfs2_log_lock(sdp); - if (sdp->sd_log_blks_free > blks) { - sdp->sd_log_blks_free -= blks; - gfs2_log_unlock(sdp); - mutex_unlock(&sdp->sd_log_reserve_mutex); - break; - } - + gfs2_log_lock(sdp); + while(sdp->sd_log_blks_free <= blks) { gfs2_log_unlock(sdp); gfs2_ail1_empty(sdp, 0); gfs2_log_flush(sdp); if (try++) gfs2_ail1_start(sdp, 0); + gfs2_log_lock(sdp); } - lock_for_trans(sdp); + sdp->sd_log_blks_free -= blks; + gfs2_log_unlock(sdp); + mutex_unlock(&sdp->sd_log_reserve_mutex); + + down_read(&sdp->sd_log_flush_lock); return 0; } @@ -224,7 +195,7 @@ int gfs2_log_reserve(struct gfs2_sbd *sdp, unsigned int blks) void gfs2_log_release(struct gfs2_sbd *sdp, unsigned int blks) { - unlock_from_trans(sdp); + up_read(&sdp->sd_log_flush_lock); gfs2_log_lock(sdp); sdp->sd_log_blks_free += blks; @@ -474,20 +445,20 @@ void gfs2_log_flush_i(struct gfs2_sbd *sdp, struct gfs2_glock *gl) ai = kzalloc(sizeof(struct gfs2_ail), GFP_NOFS | __GFP_NOFAIL); INIT_LIST_HEAD(&ai->ai_ail1_list); INIT_LIST_HEAD(&ai->ai_ail2_list); - gfs2_lock_for_flush(sdp); + + down_write(&sdp->sd_log_flush_lock); if (gl) { gfs2_log_lock(sdp); if (list_empty(&gl->gl_le.le_list)) { gfs2_log_unlock(sdp); - gfs2_unlock_from_flush(sdp); + up_write(&sdp->sd_log_flush_lock); kfree(ai); return; } gfs2_log_unlock(sdp); } - mutex_lock(&sdp->sd_log_flush_lock); gfs2_assert_withdraw(sdp, sdp->sd_log_num_buf == sdp->sd_log_commited_buf); @@ -519,9 +490,8 @@ void gfs2_log_flush_i(struct gfs2_sbd *sdp, struct gfs2_glock *gl) } gfs2_log_unlock(sdp); - mutex_unlock(&sdp->sd_log_flush_lock); sdp->sd_vfs->s_dirt = 0; - gfs2_unlock_from_flush(sdp); + up_write(&sdp->sd_log_flush_lock); kfree(ai); } @@ -573,7 +543,7 @@ void gfs2_log_commit(struct gfs2_sbd *sdp, struct gfs2_trans *tr) lops_incore_commit(sdp, tr); sdp->sd_vfs->s_dirt = 1; - unlock_from_trans(sdp); + up_read(&sdp->sd_log_flush_lock); gfs2_log_lock(sdp); if (sdp->sd_log_num_buf > gfs2_tune_get(sdp, gt_incore_log_blocks)) { @@ -591,9 +561,8 @@ void gfs2_log_commit(struct gfs2_sbd *sdp, struct gfs2_trans *tr) void gfs2_log_shutdown(struct gfs2_sbd *sdp) { - mutex_lock(&sdp->sd_log_flush_lock); + down_write(&sdp->sd_log_flush_lock); - gfs2_assert_withdraw(sdp, !atomic_read(&sdp->sd_log_trans_count)); gfs2_assert_withdraw(sdp, !sdp->sd_log_blks_reserved); gfs2_assert_withdraw(sdp, !sdp->sd_log_num_gl); gfs2_assert_withdraw(sdp, !sdp->sd_log_num_buf); @@ -618,6 +587,6 @@ void gfs2_log_shutdown(struct gfs2_sbd *sdp) sdp->sd_log_wraps++; sdp->sd_log_tail = sdp->sd_log_head; - mutex_unlock(&sdp->sd_log_flush_lock); + up_write(&sdp->sd_log_flush_lock); } -- cgit v1.2.3