ext4: Fix buffer head reference leak in no-journal mode
We found a problem with buffer head reference leaks when using an ext4
partition without a journal. In particular, calls to ext4_forget() would
not to a brelse() on the input buffer head, which will cause pages they
belong to to not be reclaimable.
Further investigation showed that all places where ext4_journal_forget() and
ext4_journal_revoke() are called are subject to the same problem. The patch
below changes __ext4_journal_forget/__ext4_journal_revoke to do an explicit
release of the buffer head when the journal handle isn't valid.
Signed-off-by: Curt Wohlgemuth <curtw@google.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
diff --git a/fs/ext4/ext4_jbd2.h b/fs/ext4/ext4_jbd2.h
index d574a85..139fb8c 100644
--- a/fs/ext4/ext4_jbd2.h
+++ b/fs/ext4/ext4_jbd2.h
@@ -131,9 +131,11 @@
int __ext4_journal_get_write_access(const char *where, handle_t *handle,
struct buffer_head *bh);
+/* When called with an invalid handle, this will still do a put on the BH */
int __ext4_journal_forget(const char *where, handle_t *handle,
struct buffer_head *bh);
+/* When called with an invalid handle, this will still do a put on the BH */
int __ext4_journal_revoke(const char *where, handle_t *handle,
ext4_fsblk_t blocknr, struct buffer_head *bh);