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authorFrederic Weisbecker <fweisbec@gmail.com>2009-04-14 05:34:25 +0200
committerFrederic Weisbecker <fweisbec@gmail.com>2009-09-14 07:18:04 +0200
commitdc8f6d8936eb244eea452af689df5ee19e635206 (patch)
treec93624678a2d2821c78048f6f7db19889eac5b3a /fs/reiserfs/super.c
parent22c963addcf426bef97a43f6e601f985f8082ed5 (diff)
kill-the-BKL/reiserfs: only acquire the write lock once in reiserfs_dirty_inode
Impact: fix a deadlock reiserfs_dirty_inode() is the super_operations::dirty_inode() callback of reiserfs. It can be called from different contexts where the write lock can be already held. But this function also grab the write lock (possibly recursively). Subsequent release of the lock before sleep will actually not release the lock if the caller of mark_inode_dirty() (which in turn calls reiserfs_dirty_inode()) already owns the lock. A typical case: reiserfs_write_end() { acquire_write_lock() mark_inode_dirty() { reiserfs_dirty_inode() { reacquire_write_lock() { journal_begin() { do_journal_begin_r() { /* * fail to release, still * one depth of lock */ release_write_lock() reiserfs_wait_on_write_block() { wait_event() The event is usually provided by something which needs the write lock but it hasn't been released. We use reiserfs_write_lock_once() here to ensure we only grab the write lock in one level. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Alessio Igor Bogani <abogani@texware.it> Cc: Jeff Mahoney <jeffm@suse.com> Cc: Chris Mason <chris.mason@oracle.com> LKML-Reference: <1239680065-25013-4-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'fs/reiserfs/super.c')
-rw-r--r--fs/reiserfs/super.c15
1 files changed, 9 insertions, 6 deletions
diff --git a/fs/reiserfs/super.c b/fs/reiserfs/super.c
index e1cfb80d0bf..58727b5b435 100644
--- a/fs/reiserfs/super.c
+++ b/fs/reiserfs/super.c
@@ -554,25 +554,28 @@ static void reiserfs_dirty_inode(struct inode *inode)
struct reiserfs_transaction_handle th;
int err = 0;
+ int lock_depth;
+
if (inode->i_sb->s_flags & MS_RDONLY) {
reiserfs_warning(inode->i_sb, "clm-6006",
"writing inode %lu on readonly FS",
inode->i_ino);
return;
}
- reiserfs_write_lock(inode->i_sb);
+ lock_depth = reiserfs_write_lock_once(inode->i_sb);
/* this is really only used for atime updates, so they don't have
** to be included in O_SYNC or fsync
*/
err = journal_begin(&th, inode->i_sb, 1);
- if (err) {
- reiserfs_write_unlock(inode->i_sb);
- return;
- }
+ if (err)
+ goto out;
+
reiserfs_update_sd(&th, inode);
journal_end(&th, inode->i_sb, 1);
- reiserfs_write_unlock(inode->i_sb);
+
+out:
+ reiserfs_write_unlock_once(inode->i_sb, lock_depth);
}
#ifdef CONFIG_QUOTA