From patchwork Fri May 14 00:29:45 2010
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Subject: [RFC] support discard in non-journal ext4
Date: Thu, 13 May 2010 14:29:45 -0000
From: Jiaying Zhang <jiayingz@google.com>
X-Patchwork-Id: 52529
Message-Id: <AANLkTinniD1Acxh8CmMd1oE72fzYvmA8aEVWEWB4TS1j@mail.gmail.com>
To: coly.li@suse.de
Cc: linux-ext4@vger.kernel.org

On Thu, May 13, 2010 at 2:08 AM, Coly Li <coly.li@suse.de> wrote:
>
>
> On 05/13/2010 01:00 PM, Jiaying Zhang Wrote:
> > This patch issues discard request for freed blocks in ext4_free_blocks()
> > if ext4 is mounted with discard option and without journal.
> >
> > Author: Jiaying Zhang <jiayingz@google.com>
> > Date:   Wed May 12 21:11:46 2010 -0700
> >
> >     Issue discard request in ext4_free_blocks() when ext4 has no journal and
> >     is mounted with discard option.
> >
> >     Signed-off-by: Jiaying Zhang <jiayingz@google.com>
> >
> > diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
> > index a291cc3..d51b79a 100644
> > --- a/fs/ext4/mballoc.c
> > +++ b/fs/ext4/mballoc.c
> > @@ -2513,6 +2513,22 @@ int ext4_mb_release(struct super_block *sb)
> >       return 0;
> >  }
> >
> > +static void ext4_issue_discard(struct super_block *sb, ext4_group_t block_group,
> > +             ext4_grpblk_t block, int count)
> > +{
> > +     int ret;
> > +     ext4_fsblk_t discard_block;
> > +
> > +     discard_block = block + ext4_group_first_block_no(sb, block_group);
> > +     trace_ext4_discard_blocks(sb,
> > +                     (unsigned long long) discard_block, count);
> > +     ret = sb_issue_discard(sb, discard_block, count);
> > +     if (ret == EOPNOTSUPP) {
> > +             ext4_warning(sb, "discard not supported, disabling");
> > +             clear_opt(EXT4_SB(sb)->s_mount_opt, DISCARD);
> > +     }
> > +}
> > +
>
> How about make it as an inline routine? Thanks.

Ok. I changed it to inline. The modified patch is attached.

Thanks!

Jiaying

>
> --
> Coly Li
> SuSE Labs
Acked-by: Coly Li <coly.li@suse.de>


commit 43e4186b502e13957544991c6a456447a6aa3aa9
Author: Jiaying Zhang <jiayingz@google.com>
Date:   Wed May 12 21:11:46 2010 -0700

    Issue discard request in ext4_free_blocks() when ext4 has no journal and
    is mounted with discard option.
    
    Signed-off-by: Jiaying Zhang <jiayingz@google.com>

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index a291cc3..ecaf7e7 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -2513,6 +2513,22 @@ int ext4_mb_release(struct super_block *sb)
 	return 0;
 }
 
+static inline void ext4_issue_discard(struct super_block *sb,
+		ext4_group_t block_group, ext4_grpblk_t block, int count)
+{
+	int ret;
+	ext4_fsblk_t discard_block;
+
+	discard_block = block + ext4_group_first_block_no(sb, block_group);
+	trace_ext4_discard_blocks(sb,
+			(unsigned long long) discard_block, count);
+	ret = sb_issue_discard(sb, discard_block, count);
+	if (ret == EOPNOTSUPP) {
+		ext4_warning(sb, "discard not supported, disabling");
+		clear_opt(EXT4_SB(sb)->s_mount_opt, DISCARD);
+	}
+}
+
 /*
  * This function is called by the jbd2 layer once the commit has finished,
  * so we know we can free the blocks that were released with that commit.
@@ -2532,22 +2548,9 @@ static void release_blocks_on_commit(journal_t *journal, transaction_t *txn)
 		mb_debug(1, "gonna free %u blocks in group %u (0x%p):",
 			 entry->count, entry->group, entry);
 
-		if (test_opt(sb, DISCARD)) {
-			int ret;
-			ext4_fsblk_t discard_block;
-
-			discard_block = entry->start_blk +
-				ext4_group_first_block_no(sb, entry->group);
-			trace_ext4_discard_blocks(sb,
-					(unsigned long long)discard_block,
-					entry->count);
-			ret = sb_issue_discard(sb, discard_block, entry->count);
-			if (ret == EOPNOTSUPP) {
-				ext4_warning(sb,
-					"discard not supported, disabling");
-				clear_opt(EXT4_SB(sb)->s_mount_opt, DISCARD);
-			}
-		}
+		if (test_opt(sb, DISCARD))
+			ext4_issue_discard(sb, entry->group,
+					entry->start_blk, entry->count);
 
 		err = ext4_mb_load_buddy(sb, entry->group, &e4b);
 		/* we expect to find existing buddy because it's pinned */
@@ -4600,6 +4603,8 @@ do_more:
 		mb_clear_bits(bitmap_bh->b_data, bit, count);
 		mb_free_blocks(inode, &e4b, bit, count);
 		ext4_mb_return_to_preallocation(inode, &e4b, block, count);
+		if (test_opt(sb, DISCARD))
+			ext4_issue_discard(sb, block_group, bit, count);
 	}
 
 	ret = ext4_free_blks_count(sb, gdp) + count;