JFS: don't use global lock in lmLogSync when local lock is sufficient

I stupidly used the global jfs_log_sem to protect log->sb_list when
implementing the shared journal stuff.  Since we already hold
LOG_LOCK, it makes more sense to use that to protect log->sb_list.
This caused horrible serialization when running on lots of jfs
volumes.

diff --git a/fs/jfs/jfs_logmgr.c b/fs/jfs/jfs_logmgr.c
index 4a98b5f997bfd686a309dc6d8a56cf0e832a6a66..d53fff5bbe37953cc1670d65a5986b5bdbd5714d 100644 (file)
--- a/fs/jfs/jfs_logmgr.c
+++ b/fs/jfs/jfs_logmgr.c
@@ -979,7 +979,6 @@ static int lmLogSync(struct jfs_log * log, int nosyncwait)
                 * We need to make sure all of the "written" metapages
                 * actually make it to disk
                 */
-               down(&jfs_log_sem);
                list_for_each_entry(sbi, &log->sb_list, log_list) {
                        filemap_fdatawrite(sbi->ipbmap->i_mapping);
                        filemap_fdatawrite(sbi->ipimap->i_mapping);
@@ -990,7 +989,6 @@ static int lmLogSync(struct jfs_log * log, int nosyncwait)
                        filemap_fdatawait(sbi->ipimap->i_mapping);
                        filemap_fdatawait(sbi->sb->s_bdev->bd_inode->i_mapping);
                }
-               up(&jfs_log_sem);
 
                lrd.logtid = 0;
                lrd.backchain = 0;
@@ -1151,8 +1149,10 @@ int lmLogOpen(struct super_block *sb)
                goto shutdown;
 
 journal_found:
+       LOG_LOCK(log);
        list_add(&sbi->log_list, &log->sb_list);
        sbi->log = log;
+       LOG_UNLOCK(log);
 
        up(&jfs_log_sem);
        return 0;
@@ -1237,8 +1237,10 @@ static int open_dummy_log(struct super_block *sb)
                }
        }
 
+       LOG_LOCK(dummy_log);
        list_add(&JFS_SBI(sb)->log_list, &dummy_log->sb_list);
        JFS_SBI(sb)->log = dummy_log;
+       LOG_UNLOCK(dummy_log);
        up(&jfs_log_sem);
 
        return 0;
@@ -1469,7 +1471,9 @@ int lmLogClose(struct super_block *sb)
        jfs_info("lmLogClose: log:0x%p", log);
 
        down(&jfs_log_sem);
+       LOG_LOCK(log);
        list_del(&sbi->log_list);
+       LOG_UNLOCK(log);
        sbi->log = NULL;
 
        /*