diff options
authorakpm@osdl.org <akpm@osdl.org>2005-04-16 15:26:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:26:36 -0700
commitd13df84ff7f3f3e26a9643c1d3cbf94cef9b5b59 (patch)
parent19272d4385126c2ac369c9f6137a27a08aee50d1 (diff)
[PATCH] jbd dirty buffer leak fix
This fixes the lots-of-fsx-linux-instances-cause-a-slow-leak bug. It's been there since 2.6.6, caused by: ftp://ftp.kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.5/2.6.5-mm4/broken-out/jbd-move-locked-buffers.patch That patch moves under-writeout ordered-data buffers onto a separate journal list during commit. It took out the old code which was based on a single list. The old code (necessarily) had logic which would restart I/O against buffers which had been redirtied while they were on the committing transaction's t_sync_datalist list. The new code only writes buffers once, ignoring redirtyings by a later transaction, which is good. But over on the truncate side of things, in journal_unmap_buffer(), we're treating buffers on the t_locked_list as inviolable things which belong to the committing transaction, and we just leave them alone during concurrent truncate-vs-commit. The net effect is that when truncate tries to invalidate a page whose buffers are on t_locked_list and have been redirtied, journal_unmap_buffer() just leaves those buffers alone. truncate will remove the page from its mapping and we end up with an anonymous clean page with dirty buffers, which is an illegal state for a page. The JBD commit will not clean those buffers as they are removed from t_locked_list. The VM (try_to_free_buffers) cannot reclaim these pages. The patch teaches journal_unmap_buffer() about buffers which are on the committing transaction's t_locked_list. These buffers have been written and I/O has completed. We can take them off the transaction and undirty them within the context of journal_invalidatepage()->journal_unmap_buffer(). Acked-by: "Stephen C. Tweedie" <sct@redhat.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
1 files changed, 11 insertions, 2 deletions
diff --git a/fs/jbd/transaction.c b/fs/jbd/transaction.c
index 932e7c1ef4a..77b7662b840 100644
--- a/fs/jbd/transaction.c
+++ b/fs/jbd/transaction.c
@@ -1812,7 +1812,17 @@ static int journal_unmap_buffer(journal_t *journal, struct buffer_head *bh)
} else if (transaction == journal->j_committing_transaction) {
- /* If it is committing, we simply cannot touch it. We
+ if (jh->b_jlist == BJ_Locked) {
+ /*
+ * The buffer is on the committing transaction's locked
+ * list. We have the buffer locked, so I/O has
+ * completed. So we can nail the buffer now.
+ */
+ may_free = __dispose_buffer(jh, transaction);
+ goto zap_buffer;
+ }
+ /*
+ * If it is committing, we simply cannot touch it. We
* can remove it's next_transaction pointer from the
* running transaction if that is set, but nothing
* else. */
@@ -1887,7 +1897,6 @@ int journal_invalidatepage(journal_t *journal,
unsigned int next_off = curr_off + bh->b_size;
next = bh->b_this_page;
- /* AKPM: doing lock_buffer here may be overly paranoid */
if (offset <= curr_off) {
/* This block is wholly outside the truncation point */