From e17fc0a1ccf88f6d4dcb363729f3141b0958c325 Mon Sep 17 00:00:00 2001 From: David Woodhouse Date: Sat, 9 Aug 2008 16:42:20 +0100 Subject: Allow elevators to sort/merge discard requests MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit But blkdev_issue_discard() still emits requests which are interpreted as soft barriers, because naïve callers might otherwise issue subsequent writes to those same sectors, which might cross on the queue (if they're reallocated quickly enough). Callers still _can_ issue non-barrier discard requests, but they have to take care of queue ordering for themselves. Signed-off-by: David Woodhouse Signed-off-by: Jens Axboe --- include/linux/fs.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'include/linux/fs.h') diff --git a/include/linux/fs.h b/include/linux/fs.h index 88358ca6af2..860689f541b 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -87,7 +87,8 @@ extern int dir_notify_enable; #define WRITE_SYNC (WRITE | (1 << BIO_RW_SYNC)) #define SWRITE_SYNC (SWRITE | (1 << BIO_RW_SYNC)) #define WRITE_BARRIER (WRITE | (1 << BIO_RW_BARRIER)) -#define WRITE_DISCARD (WRITE | (1 << BIO_RW_DISCARD)) +#define DISCARD_NOBARRIER (1 << BIO_RW_DISCARD) +#define DISCARD_BARRIER ((1 << BIO_RW_DISCARD) | (1 << BIO_RW_BARRIER)) #define SEL_IN 1 #define SEL_OUT 2 -- cgit