From 9924a92a8c217576bd2a2b1bbbb854462f1a00ae Mon Sep 17 00:00:00 2001 From: Theodore Ts'o Date: Fri, 8 Feb 2013 21:59:22 -0500 Subject: ext4: pass context information to jbd2__journal_start() So we can better understand what bits of ext4 are responsible for long-running jbd2 handles, use jbd2__journal_start() so we can pass context information for logging purposes. The recommended way for finding the longer-running handles is: T=/sys/kernel/debug/tracing EVENT=$T/events/jbd2/jbd2_handle_stats echo "interval > 5" > $EVENT/filter echo 1 > $EVENT/enable ./run-my-fs-benchmark cat $T/trace > /tmp/problem-handles This will list handles that were active for longer than 20ms. Having longer-running handles is bad, because a commit started at the wrong time could stall for those 20+ milliseconds, which could delay an fsync() or an O_SYNC operation. Here is an example line from the trace file describing a handle which lived on for 311 jiffies, or over 1.2 seconds: postmark-2917 [000] .... 196.435786: jbd2_handle_stats: dev 254,32 tid 570 type 2 line_no 2541 interval 311 sync 0 requested_blocks 1 dirtied_blocks 0 Signed-off-by: "Theodore Ts'o" --- fs/ext4/acl.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'fs/ext4/acl.c') diff --git a/fs/ext4/acl.c b/fs/ext4/acl.c index e6e0d988439b..406cf8bb12d5 100644 --- a/fs/ext4/acl.c +++ b/fs/ext4/acl.c @@ -324,7 +324,7 @@ ext4_acl_chmod(struct inode *inode) if (error) return error; retry: - handle = ext4_journal_start(inode, + handle = ext4_journal_start(inode, EXT4_HT_XATTR, EXT4_DATA_TRANS_BLOCKS(inode->i_sb)); if (IS_ERR(handle)) { error = PTR_ERR(handle); @@ -422,7 +422,8 @@ ext4_xattr_set_acl(struct dentry *dentry, const char *name, const void *value, acl = NULL; retry: - handle = ext4_journal_start(inode, EXT4_DATA_TRANS_BLOCKS(inode->i_sb)); + handle = ext4_journal_start(inode, EXT4_HT_XATTR, + EXT4_DATA_TRANS_BLOCKS(inode->i_sb)); if (IS_ERR(handle)) { error = PTR_ERR(handle); goto release_and_out; -- cgit v1.2.3