From ca572727dbb945e443564029a495157fd2e72995 Mon Sep 17 00:00:00 2001 From: jan Blunck Date: Wed, 26 May 2010 14:44:53 -0700 Subject: fs/: do not fallback to default_llseek() when readdir() uses BKL Do not use the fallback default_llseek() if the readdir operation of the filesystem still uses the big kernel lock. Since llseek() modifies file->f_pos of the directory directly it may need locking to not confuse readdir which usually uses file->f_pos directly as well Since the special characteristics of the BKL (unlocked on schedule) are not necessary in this case, the inode mutex can be used for locking as provided by generic_file_llseek(). This is only possible since all filesystems, except reiserfs, either use a directory as a flat file or with disk address offsets. Reiserfs on the other hand uses a 32bit hash off the filename as the offset so generic_file_llseek() can get used as well since the hash is always smaller than sb->s_maxbytes (= (512 << 32) - blocksize). Signed-off-by: Jan Blunck Acked-by: Jan Kara Acked-by: Anders Larsen Cc: Frederic Weisbecker Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/qnx4/dir.c | 1 + 1 file changed, 1 insertion(+) (limited to 'fs/qnx4') diff --git a/fs/qnx4/dir.c b/fs/qnx4/dir.c index 6f30c3d..3d3fd46 100644 --- a/fs/qnx4/dir.c +++ b/fs/qnx4/dir.c @@ -77,6 +77,7 @@ out: const struct file_operations qnx4_dir_operations = { + .llseek = generic_file_llseek, .read = generic_read_dir, .readdir = qnx4_readdir, .fsync = simple_fsync, -- cgit v1.1