Reject zero sized reads as soon as we know our I/O length, and don't borther with locks or allocations that might have to be cleaned up otherwise.
Signed-off-by: Christoph Hellwig <[email protected]> Index: linux-2.6/fs/direct-io.c =================================================================== --- linux-2.6.orig/fs/direct-io.c 2011-06-11 12:10:10.205165161 +0200 +++ linux-2.6/fs/direct-io.c 2011-06-11 12:12:49.161823781 +0200 @@ -1200,6 +1200,10 @@ __blockdev_direct_IO(int rw, struct kioc } } + /* watch out for a 0 len io from a tricksy fs */ + if (rw == READ && end == offset) + return 0; + dio = kmalloc(sizeof(*dio), GFP_KERNEL); retval = -ENOMEM; if (!dio) @@ -1213,8 +1217,7 @@ __blockdev_direct_IO(int rw, struct kioc dio->flags = flags; if (dio->flags & DIO_LOCKING) { - /* watch out for a 0 len io from a tricksy fs */ - if (rw == READ && end > offset) { + if (rw == READ) { struct address_space *mapping = iocb->ki_filp->f_mapping; -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
