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authorFrederic Weisbecker <fweisbec@gmail.com>2009-04-14 05:34:24 +0200
committerFrederic Weisbecker <fweisbec@gmail.com>2009-09-14 07:18:03 +0200
commit22c963addcf426bef97a43f6e601f985f8082ed5 (patch)
treef71ae95fd1eee899c446ebb03a3cc02fe24daf3c /fs/reiserfs
parentdaf88c898312a22b5385655bc6e0b064eaa2efba (diff)
kill-the-BKL/reiserfs: lock only once in reiserfs_truncate_file
Impact: fix a deadlock reiserfs_truncate_file() can be called from multiple context where the write lock can be already hold or not. This function also acquire (possibly recursively) the write lock. Subsequent releases before sleeping will not actually release the lock because we may be in more than one lock depth degree. A typical case is: reiserfs_file_release { acquire_the_lock() reiserfs_truncate_file() reacquire_the_lock() journal_begin() { do_journal_begin_r() { reiserfs_wait_on_write_block() { /* * Not released because still one * depth owned */ release_lock() wait_for_event() At this stage the event never happen because the one which provides it needs the write lock. We use reiserfs_write_lock_once() here to ensure that we don't acquire the write lock recursively. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Alessio Igor Bogani <abogani@texware.it> Cc: Jeff Mahoney <jeffm@suse.com> Cc: Alexander Beregalov <a.beregalov@gmail.com> Cc: Chris Mason <chris.mason@oracle.com> LKML-Reference: <1239680065-25013-3-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'fs/reiserfs')
-rw-r--r--fs/reiserfs/inode.c10
1 files changed, 7 insertions, 3 deletions
diff --git a/fs/reiserfs/inode.c b/fs/reiserfs/inode.c
index 1893c8198439..cc70b56bf6f2 100644
--- a/fs/reiserfs/inode.c
+++ b/fs/reiserfs/inode.c
@@ -2079,8 +2079,9 @@ int reiserfs_truncate_file(struct inode *inode, int update_timestamps)
int error;
struct buffer_head *bh = NULL;
int err2;
+ int lock_depth;
- reiserfs_write_lock(inode->i_sb);
+ lock_depth = reiserfs_write_lock_once(inode->i_sb);
if (inode->i_size > 0) {
error = grab_tail_page(inode, &page, &bh);
@@ -2149,14 +2150,17 @@ int reiserfs_truncate_file(struct inode *inode, int update_timestamps)
page_cache_release(page);
}
- reiserfs_write_unlock(inode->i_sb);
+ reiserfs_write_unlock_once(inode->i_sb, lock_depth);
+
return 0;
out:
if (page) {
unlock_page(page);
page_cache_release(page);
}
- reiserfs_write_unlock(inode->i_sb);
+
+ reiserfs_write_unlock_once(inode->i_sb, lock_depth);
+
return error;
}