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authorJoel Becker <joel.becker@oracle.com>2008-09-12 02:35:47 +0400
committerMark Fasheh <mfasheh@suse.com>2009-01-05 19:40:30 +0300
commite06c8227fd94ec181849ba206bf032be31c4295c (patch)
tree67261cd94aa86dc6112d7de74304c2a1af5b64fb /fs/jbd2/commit.c
parent754938c142ae0c28360426c43f965ddc5164b21e (diff)
downloadlinux-e06c8227fd94ec181849ba206bf032be31c4295c.tar.xz
jbd2: Add buffer triggers
Filesystems often to do compute intensive operation on some metadata. If this operation is repeated many times, it can be very expensive. It would be much nicer if the operation could be performed once before a buffer goes to disk. This adds triggers to jbd2 buffer heads. Just before writing a metadata buffer to the journal, jbd2 will optionally call a commit trigger associated with the buffer. If the journal is aborted, an abort trigger will be called on any dirty buffers as they are dropped from pending transactions. ocfs2 will use this feature. Initially I tried to come up with a more generic trigger that could be used for non-buffer-related events like transaction completion. It doesn't tie nicely, because the information a buffer trigger needs (specific to a journal_head) isn't the same as what a transaction trigger needs (specific to a tranaction_t or perhaps journal_t). So I implemented a buffer set, with the understanding that journal/transaction wide triggers should be implemented separately. There is only one trigger set allowed per buffer. I can't think of any reason to attach more than one set. Contrast this with a journal or transaction in which multiple places may want to watch the entire transaction separately. The trigger sets are considered static allocation from the jbd2 perspective. ocfs2 will just have one trigger set per block type, setting the same set on every bh of the same type. Signed-off-by: Joel Becker <joel.becker@oracle.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: <linux-ext4@vger.kernel.org> Signed-off-by: Mark Fasheh <mfasheh@suse.com>
Diffstat (limited to 'fs/jbd2/commit.c')
-rw-r--r--fs/jbd2/commit.c9
1 files changed, 9 insertions, 0 deletions
diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c
index ebc667bc54a8..c8a1bace685a 100644
--- a/fs/jbd2/commit.c
+++ b/fs/jbd2/commit.c
@@ -509,6 +509,10 @@ void jbd2_journal_commit_transaction(journal_t *journal)
if (is_journal_aborted(journal)) {
clear_buffer_jbddirty(jh2bh(jh));
JBUFFER_TRACE(jh, "journal is aborting: refile");
+ jbd2_buffer_abort_trigger(jh,
+ jh->b_frozen_data ?
+ jh->b_frozen_triggers :
+ jh->b_triggers);
jbd2_journal_refile_buffer(journal, jh);
/* If that was the last one, we need to clean up
* any descriptor buffers which may have been
@@ -844,6 +848,9 @@ restart_loop:
* data.
*
* Otherwise, we can just throw away the frozen data now.
+ *
+ * We also know that the frozen data has already fired
+ * its triggers if they exist, so we can clear that too.
*/
if (jh->b_committed_data) {
jbd2_free(jh->b_committed_data, bh->b_size);
@@ -851,10 +858,12 @@ restart_loop:
if (jh->b_frozen_data) {
jh->b_committed_data = jh->b_frozen_data;
jh->b_frozen_data = NULL;
+ jh->b_frozen_triggers = NULL;
}
} else if (jh->b_frozen_data) {
jbd2_free(jh->b_frozen_data, bh->b_size);
jh->b_frozen_data = NULL;
+ jh->b_frozen_triggers = NULL;
}
spin_lock(&journal->j_list_lock);