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ext4: Fix buffer head reference leak in no-journal mode

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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>
This commit is contained in:
Curt Wohlgemuth
2009-07-13 09:07:20 -04:00
committed by Theodore Ts'o
parent 62e086be5d
commit e6b5d30104
3 changed files with 8 additions and 4 deletions
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2
fs/ext4/ext4_jbd2.h
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@@ -131,9 +131,11 @@ int __ext4_journal_get_undo_access(const char *where, handle_t *handle,
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);