From e6b5d30104db5f34110678ecab14988f1f1eff63 Mon Sep 17 00:00:00 2001 From: Curt Wohlgemuth Date: Mon, 13 Jul 2009 09:07:20 -0400 Subject: [PATCH] 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 Signed-off-by: "Theodore Ts'o" --- fs/ext4/ext4_jbd2.c | 4 ++++ fs/ext4/ext4_jbd2.h | 2 ++ fs/ext4/inode.c | 6 ++---- 3 files changed, 8 insertions(+), 4 deletions(-) diff --git a/fs/ext4/ext4_jbd2.c b/fs/ext4/ext4_jbd2.c index ad13a84644e1..eb27fd0f2ee8 100644 --- a/fs/ext4/ext4_jbd2.c +++ b/fs/ext4/ext4_jbd2.c @@ -43,6 +43,8 @@ int __ext4_journal_forget(const char *where, handle_t *handle, ext4_journal_abort_handle(where, __func__, bh, handle, err); } + else + brelse(bh); return err; } @@ -57,6 +59,8 @@ int __ext4_journal_revoke(const char *where, handle_t *handle, ext4_journal_abort_handle(where, __func__, bh, handle, err); } + else + brelse(bh); return err; } diff --git a/fs/ext4/ext4_jbd2.h b/fs/ext4/ext4_jbd2.h index d574a85aca56..139fb8cb87e4 100644 --- a/fs/ext4/ext4_jbd2.h +++ b/fs/ext4/ext4_jbd2.h @@ -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); diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index c98e3afea30a..f9c642b22efa 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -78,16 +78,14 @@ static int ext4_inode_is_fast_symlink(struct inode *inode) * but there may still be a record of it in the journal, and that record * still needs to be revoked. * - * If the handle isn't valid we're not journaling so there's nothing to do. + * If the handle isn't valid we're not journaling, but we still need to + * call into ext4_journal_revoke() to put the buffer head. */ int ext4_forget(handle_t *handle, int is_metadata, struct inode *inode, struct buffer_head *bh, ext4_fsblk_t blocknr) { int err; - if (!ext4_handle_valid(handle)) - return 0; - might_sleep(); BUFFER_TRACE(bh, "enter"); -- GitLab