Resend: [PATCH] blkdev: fix blkdev_issue_zeroout return value

[Dmitry Monakhov <dmonakhov@openvz.org>]

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Hi Jens,
Seems that my first mail was missed somewhere.  
I've found couple of trivial issues in blkdev_issue_zeroout()
implementation. Unfortunately I've miss during initial testing phase
because always called it with BARRIER|WAIT flags.


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>From 5eb4d762ad8fe146ee638fb1b2d7730db3e3ca4b Mon Sep 17 00:00:00 2001
From: Dmitry Monakhov <dmonakhov@openvz.org>
Date: Tue, 27 Jul 2010 17:12:27 +0400
Subject: [PATCH] blkdev: fix blkdev_issue_zeroout return value

- If function called without barrier option retvalue is incorrect
- Add io_schedule() between loops


 diff --git a/block/blk-lib.c b/block/blk-lib.c
index d0216b9..a8d6a21 100644

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
---
 block/blk-lib.c |   15 +++++++++++----
 1 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/block/blk-lib.c b/block/blk-lib.c
index d0216b9..a8d6a21 100644
--- a/block/blk-lib.c
+++ b/block/blk-lib.c
@@ -157,7 +157,7 @@ static void bio_batch_end_io(struct bio *bio, int err)
 int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
 			sector_t nr_sects, gfp_t gfp_mask, unsigned long flags)
 {
-	int ret = 0;
+	int ret;
 	struct bio *bio;
 	struct bio_batch bb;
 	unsigned int sz, issued = 0;
@@ -175,11 +175,14 @@ int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
 			return ret;
 	}
 submit:
+	ret = 0;
 	while (nr_sects != 0) {
 		bio = bio_alloc(gfp_mask,
 				min(nr_sects, (sector_t)BIO_MAX_PAGES));
-		if (!bio)
+		if (!bio) {
+			ret = -ENOMEM;
 			break;
+		}
 
 		bio->bi_sector = sector;
 		bio->bi_bdev   = bdev;
@@ -198,6 +201,7 @@ submit:
 			if (ret < (sz << 9))
 				break;
 		}
+		ret = 0;
 		issued++;
 		submit_bio(WRITE, bio);
 	}
@@ -218,15 +222,18 @@ submit:
 		/* One of bios in the batch was completed with error.*/
 		ret = -EIO;
 
-	if (ret)
+	if (ret && ret != -ENOMEM)
 		goto out;
 
 	if (test_bit(BIO_EOPNOTSUPP, &bb.flags)) {
 		ret = -EOPNOTSUPP;
 		goto out;
 	}
-	if (nr_sects != 0)
+	if (nr_sects != 0) {
+		if (ret == -ENOMEM)
+			io_schedule();
 		goto submit;
+	}
 out:
 	return ret;
 }
-- 
1.6.6.1