[PATCH 3/4] ext4: convert extent zeroout to generic function

[PATCH 3/4] ext4: convert extent zeroout to generic function

[Dmitry Monakhov]

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
---
 fs/ext4/extents.c |   70 +++-------------------------------------------------
 1 files changed, 4 insertions(+), 66 deletions(-)

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 765a482..ff4473a 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -2432,76 +2432,14 @@ void ext4_ext_release(struct super_block *sb)
 #endif
 }
 
-static void bi_complete(struct bio *bio, int error)
-{
-	complete((struct completion *)bio->bi_private);
-}
-
 /* FIXME!! we need to try to merge to left or right after zero-out  */
 static int ext4_ext_zeroout(struct inode *inode, struct ext4_extent *ex)
 {
-	int ret = -EIO;
-	struct bio *bio;
-	int blkbits, blocksize;
-	sector_t ee_pblock;
-	struct completion event;
-	unsigned int ee_len, len, done, offset;
-
-
-	blkbits   = inode->i_blkbits;
-	blocksize = inode->i_sb->s_blocksize;
-	ee_len    = ext4_ext_get_actual_len(ex);
-	ee_pblock = ext_pblock(ex);
+	sector_t nr_sects = ((sector_t)ext4_ext_get_actual_len(ex)) <<
+		inode->i_blkbits;
 
-	/* convert ee_pblock to 512 byte sectors */
-	ee_pblock = ee_pblock << (blkbits - 9);
-
-	while (ee_len > 0) {
-
-		if (ee_len > BIO_MAX_PAGES)
-			len = BIO_MAX_PAGES;
-		else
-			len = ee_len;
-
-		bio = bio_alloc(GFP_NOIO, len);
-		bio->bi_sector = ee_pblock;
-		bio->bi_bdev   = inode->i_sb->s_bdev;
-
-		done = 0;
-		offset = 0;
-		while (done < len) {
-			ret = bio_add_page(bio, ZERO_PAGE(0),
-							blocksize, offset);
-			if (ret != blocksize) {
-				/*
-				 * We can't add any more pages because of
-				 * hardware limitations.  Start a new bio.
-				 */
-				break;
-			}
-			done++;
-			offset += blocksize;
-			if (offset >= PAGE_CACHE_SIZE)
-				offset = 0;
-		}
-
-		init_completion(&event);
-		bio->bi_private = &event;
-		bio->bi_end_io = bi_complete;
-		submit_bio(WRITE, bio);
-		wait_for_completion(&event);

Re: [PATCH 2/4] block: support compat discard mode by default.

[Dmitry Monakhov]

Dmitry Monakhov <dmonakhov@openvz.org> writes:

> Currently there are many filesystems which has implemented
> discard support, but ssd discs not widely used yet.
> Let's allow user to use compat discard mode by default.
> After this feature is enabled by default for all devices which has
> no native discard support it will be possible to use this feature
> simply by passing appropriate mount option to fs (-odiscard in ext4)
BTW i've run tested ext4 with -odiscard option, and it survived more
24hour of stress tests test which consists of fsstress, compilation,
and etc
>
> This default option has many advantages:
> - Hope that this helps in real filesystem testing.
> - People who are crazy about data security whould be really happy.
> - Virtual machine developers also would like this feature.
>
> Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
> ---
>  include/linux/blkdev.h |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
> index c762c9f..d7d028c 100644
> --- a/include/linux/blkdev.h
> +++ b/include/linux/blkdev.h
> @@ -1010,7 +1010,7 @@ static inline int sb_issue_discard(struct super_block *sb,
>  	block <<= (sb->s_blocksize_bits - 9);
>  	nr_blocks <<= (sb->s_blocksize_bits - 9);
>  	return blkdev_issue_discard(sb->s_bdev, block, nr_blocks, GFP_KERNEL,
> -				    DISCARD_FL_BARRIER);
> +				    DISCARD_FL_BARRIER|DISCARD_FL_COMPAT);
>  }
>  
>  extern int blk_verify_command(unsigned char *cmd, fmode_t has_write_perm);