[PATCH v7 04/12] ext4: extend ext4_mb_mark_context to support allocation under journal

Kemeng Shi posted 12 patches 5 months, 1 week ago
There is a newer version of this series
[PATCH v7 04/12] ext4: extend ext4_mb_mark_context to support allocation under journal
Posted by Kemeng Shi 5 months, 1 week ago
Previously, ext4_mb_mark_context is only called under fast commit
replay path, so there is no valid handle when we update block bitmap
and group descriptor. This patch try to extend ext4_mb_mark_context
to be used by code under journal. There are several improvement:
1. add "handle_t *handle" to struct ext4_mark_context to journal block
bitmap and group descriptor update inside ext4_mb_mark_context (the
added journal code is based on ext4_mb_mark_diskspace_used where
ext4_mb_mark_context is going to be used.)
2. add EXT4_MB_BITMAP_MARKED_CHECK flag to control check if bits in block
bitmap are already marked as allocation code under journal asserts that
all bits to be changed are not marked before.
3. add "ext4_grpblk_t changed" to struct ext4_mark_context to notify number
of bits in block bitmap has changed.

Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
---
 fs/ext4/mballoc.c | 64 ++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 49 insertions(+), 15 deletions(-)

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index cd2fd5dbfcdd..bdf07b2904ca 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -3953,26 +3953,47 @@ void ext4_exit_mballoc(void)
 	ext4_groupinfo_destroy_slabs();
 }
 
+#define EXT4_MB_BITMAP_MARKED_CHECK 0x0001
+#define EXT4_MB_SYNC_UPDATE 0x0002
 static int
-ext4_mb_mark_context(struct super_block *sb, bool state, ext4_group_t group,
-		     ext4_grpblk_t blkoff, ext4_grpblk_t len)
+ext4_mb_mark_context(handle_t *handle, struct super_block *sb, bool state,
+		     ext4_group_t group, ext4_grpblk_t blkoff,
+		     ext4_grpblk_t len, int flags, ext4_grpblk_t *ret_changed)
 {
 	struct ext4_sb_info *sbi = EXT4_SB(sb);
 	struct buffer_head *bitmap_bh = NULL;
 	struct ext4_group_desc *gdp;
 	struct buffer_head *gdp_bh;
 	int err;
-	unsigned int i, already, changed;
+	unsigned int i, already, changed = len;
 
+	if (ret_changed)
+		*ret_changed = 0;
 	bitmap_bh = ext4_read_block_bitmap(sb, group);
 	if (IS_ERR(bitmap_bh))
 		return PTR_ERR(bitmap_bh);
 
+	if (handle) {
+		BUFFER_TRACE(bitmap_bh, "getting write access");
+		err = ext4_journal_get_write_access(handle, sb, bitmap_bh,
+						    EXT4_JTR_NONE);
+		if (err)
+			goto out_err;
+	}
+
 	err = -EIO;
 	gdp = ext4_get_group_desc(sb, group, &gdp_bh);
 	if (!gdp)
 		goto out_err;
 
+	if (handle) {
+		BUFFER_TRACE(gdp_bh, "get_write_access");
+		err = ext4_journal_get_write_access(handle, sb, gdp_bh,
+						    EXT4_JTR_NONE);
+		if (err)
+			goto out_err;
+	}
+
 	ext4_lock_group(sb, group);
 	if (ext4_has_group_desc_csum(sb) &&
 	    (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT))) {
@@ -3981,12 +4002,14 @@ ext4_mb_mark_context(struct super_block *sb, bool state, ext4_group_t group,
 			ext4_free_clusters_after_init(sb, group, gdp));
 	}
 
-	already = 0;
-	for (i = 0; i < len; i++)
-		if (mb_test_bit(blkoff + i, bitmap_bh->b_data) ==
-				state)
-			already++;
-	changed = len - already;
+	if (flags & EXT4_MB_BITMAP_MARKED_CHECK) {
+		already = 0;
+		for (i = 0; i < len; i++)
+			if (mb_test_bit(blkoff + i, bitmap_bh->b_data) ==
+					state)
+				already++;
+		changed = len - already;
+	}
 
 	if (state) {
 		mb_set_bits(bitmap_bh->b_data, blkoff, len);
@@ -4001,6 +4024,8 @@ ext4_mb_mark_context(struct super_block *sb, bool state, ext4_group_t group,
 	ext4_block_bitmap_csum_set(sb, gdp, bitmap_bh);
 	ext4_group_desc_csum_set(sb, group, gdp);
 	ext4_unlock_group(sb, group);
+	if (ret_changed)
+		*ret_changed = changed;
 
 	if (sbi->s_log_groups_per_flex) {
 		ext4_group_t flex_group = ext4_flex_group(sbi, group);
@@ -4013,15 +4038,17 @@ ext4_mb_mark_context(struct super_block *sb, bool state, ext4_group_t group,
 			atomic64_add(changed, &fg->free_clusters);
 	}
 
-	err = ext4_handle_dirty_metadata(NULL, NULL, bitmap_bh);
+	err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
 	if (err)
 		goto out_err;
-	err = ext4_handle_dirty_metadata(NULL, NULL, gdp_bh);
+	err = ext4_handle_dirty_metadata(handle, NULL, gdp_bh);
 	if (err)
 		goto out_err;
 
-	sync_dirty_buffer(bitmap_bh);
-	sync_dirty_buffer(gdp_bh);
+	if (flags & EXT4_MB_SYNC_UPDATE) {
+		sync_dirty_buffer(bitmap_bh);
+		sync_dirty_buffer(gdp_bh);
+	}
 
 out_err:
 	brelse(bitmap_bh);
@@ -4181,7 +4208,11 @@ void ext4_mb_mark_bb(struct super_block *sb, ext4_fsblk_t block,
 			break;
 		}
 
-		err = ext4_mb_mark_context(sb, state, group, blkoff, clen);
+		err = ext4_mb_mark_context(NULL, sb, state,
+					   group, blkoff, clen,
+					   EXT4_MB_BITMAP_MARKED_CHECK |
+					   EXT4_MB_SYNC_UPDATE,
+					   NULL);
 		if (err)
 			break;
 
@@ -6398,7 +6429,10 @@ static void ext4_free_blocks_simple(struct inode *inode, ext4_fsblk_t block,
 	ext4_grpblk_t blkoff;
 
 	ext4_get_group_no_and_offset(sb, block, &group, &blkoff);
-	ext4_mb_mark_context(sb, false, group, blkoff, count);
+	ext4_mb_mark_context(NULL, sb, false, group, blkoff, count,
+			     EXT4_MB_BITMAP_MARKED_CHECK |
+			     EXT4_MB_SYNC_UPDATE,
+			     NULL);
 }
 
 /**
-- 
2.30.0
Re: [PATCH v7 04/12] ext4: extend ext4_mb_mark_context to support allocation under journal
Posted by Ritesh Harjani (IBM) 5 months ago
Kemeng Shi <shikemeng@huaweicloud.com> writes:

> Previously, ext4_mb_mark_context is only called under fast commit
> replay path, so there is no valid handle when we update block bitmap
> and group descriptor. This patch try to extend ext4_mb_mark_context
> to be used by code under journal. There are several improvement:
> 1. add "handle_t *handle" to struct ext4_mark_context to journal block
> bitmap and group descriptor update inside ext4_mb_mark_context (the
> added journal code is based on ext4_mb_mark_diskspace_used where
> ext4_mb_mark_context is going to be used.)

> 2. add EXT4_MB_BITMAP_MARKED_CHECK flag to control check if bits in block
> bitmap are already marked as allocation code under journal asserts that
> all bits to be changed are not marked before.

Maybe we can reword this to... 
Adds a flag argument to ext4_mb_mark_context() which controls
a. EXT4_MB_BITMAP_MARKED_CHECK - whether block bitmap checking is needed.
b. EXT4_MB_SYNC_UPDATE - whether dirty buffers (bitmap and group descriptor) needs sync.


> 3. add "ext4_grpblk_t changed" to struct ext4_mark_context to notify number
> of bits in block bitmap has changed.

We should remove above point 3 as there is no "struct ext4_mark_context"
in this v7 series.

>
> Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
> ---
>  fs/ext4/mballoc.c | 64 ++++++++++++++++++++++++++++++++++++-----------
>  1 file changed, 49 insertions(+), 15 deletions(-)


The changes looks good to me. With commit msg updated, feel free to add-

Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>