diff mbox

[v3] xfs: use iomap new flag for newly allocated delalloc blocks

Message ID 20170307223319.GA1626@infradead.org (mailing list archive)
State Superseded, archived
Headers show

Commit Message

Christoph Hellwig March 7, 2017, 10:33 p.m. UTC 
I still really hate that new xfs_bmapi_reserve_delalloc parameter,
as there shouldn't be any need for it in the caller.   I also don't
think the existing asserts there are very helpful, so I'd suggest
to just remove them.

Below is my quick hack of your patch with that edited in, but be aware
that it's completely untested.

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Comments

Brian Foster March 8, 2017, 12:30 p.m. UTC | #1 
On Tue, Mar 07, 2017 at 02:33:19PM -0800, Christoph Hellwig wrote:
> I still really hate that new xfs_bmapi_reserve_delalloc parameter,
> as there shouldn't be any need for it in the caller.   I also don't
> think the existing asserts there are very helpful, so I'd suggest
> to just remove them.
> 

Ok, fair enough.. v4 it is. I'll just warn about the not up-to-date got
in the comment.

Brian

> Below is my quick hack of your patch with that edited in, but be aware
> that it's completely untested.
> 
> diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
> index a9c66d47757a..f32d12cfa42a 100644
> --- a/fs/xfs/libxfs/xfs_bmap.c
> +++ b/fs/xfs/libxfs/xfs_bmap.c
> @@ -4150,6 +4150,19 @@ xfs_bmapi_read(
>  	return 0;
>  }
>  
> +/*
> + * Add a delayed allocation extent to an inode. Blocks are reserved from the
> + * global pool and the extent inserted into the inode in-core extent tree.
> + *
> + * On entry, got refers to the first extent beyond the offset of the extent to
> + * allocate or eof is specified if no such extent exists. On return, got refers
> + * to the newly allocated portion of the extent, which may be a subset of actual
> + * entry in the inodes extent list if it has been merged.
> + * 
> + * This difference is useful for callers that must distinguish newly allocated
> + * blocks from preexisting delalloc blocks within the range of the allocation
> + * request (in order to properly handle buffered write failure, for example).
> + */
>  int
>  xfs_bmapi_reserve_delalloc(
>  	struct xfs_inode	*ip,
> @@ -4236,13 +4249,8 @@ xfs_bmapi_reserve_delalloc(
>  	got->br_startblock = nullstartblock(indlen);
>  	got->br_blockcount = alen;
>  	got->br_state = XFS_EXT_NORM;
> -	xfs_bmap_add_extent_hole_delay(ip, whichfork, lastx, got);
>  
> -	/*
> -	 * Update our extent pointer, given that xfs_bmap_add_extent_hole_delay
> -	 * might have merged it into one of the neighbouring ones.
> -	 */
> -	xfs_bmbt_get_all(xfs_iext_get_ext(ifp, *lastx), got);
> +	xfs_bmap_add_extent_hole_delay(ip, whichfork, lastx, got);
>  
>  	/*
>  	 * Tag the inode if blocks were preallocated. Note that COW fork
> @@ -4254,10 +4262,6 @@ xfs_bmapi_reserve_delalloc(
>  	if (whichfork == XFS_COW_FORK && (prealloc || aoff < off || alen > len))
>  		xfs_inode_set_cowblocks_tag(ip);
>  
> -	ASSERT(got->br_startoff <= aoff);
> -	ASSERT(got->br_startoff + got->br_blockcount >= aoff + alen);
> -	ASSERT(isnullstartblock(got->br_startblock));
> -	ASSERT(got->br_state == XFS_EXT_NORM);
>  	return 0;
>  
>  out_unreserve_blocks:
> diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
> index 41662fb14e87..ce39d0143567 100644
> --- a/fs/xfs/xfs_iomap.c
> +++ b/fs/xfs/xfs_iomap.c
> @@ -613,7 +613,8 @@ xfs_file_iomap_begin_delay(
>  
>  retry:
>  	error = xfs_bmapi_reserve_delalloc(ip, XFS_DATA_FORK, offset_fsb,
> -			end_fsb - offset_fsb, prealloc_blocks, &got, &idx, eof);
> +			end_fsb - offset_fsb, prealloc_blocks, &got, &idx,
> +			eof);
>  	switch (error) {
>  	case 0:
>  		break;
> @@ -630,6 +631,12 @@ xfs_file_iomap_begin_delay(
>  		goto out_unlock;
>  	}
>  
> +	/*
> +	 * IOMAP_F_NEW controls whether we punch out delalloc blocks if the
> +	 * write happens to fail, which means we can't combine newly allocated
> +	 * blocks with preexisting delalloc blocks in the same iomap.
> +	 */
> +	iomap->flags = IOMAP_F_NEW;
>  	trace_xfs_iomap_alloc(ip, offset, count, 0, &got);
>  done:
>  	if (isnullstartblock(got.br_startblock))
> @@ -1071,16 +1078,22 @@ xfs_file_iomap_end_delalloc(
>  	struct xfs_inode	*ip,
>  	loff_t			offset,
>  	loff_t			length,
> -	ssize_t			written)
> +	ssize_t			written,
> +	struct iomap		*iomap)
>  {
>  	struct xfs_mount	*mp = ip->i_mount;
>  	xfs_fileoff_t		start_fsb;
>  	xfs_fileoff_t		end_fsb;
>  	int			error = 0;
>  
> -	/* behave as if the write failed if drop writes is enabled */
> -	if (xfs_mp_drop_writes(mp))
> +	/*
> +	 * Behave as if the write failed if drop writes is enabled. Set the NEW
> +	 * flag to force delalloc cleanup.
> +	 */
> +	if (xfs_mp_drop_writes(mp)) {
> +		iomap->flags |= IOMAP_F_NEW;
>  		written = 0;
> +	}
>  
>  	/*
>  	 * start_fsb refers to the first unused block after a short write. If
> @@ -1094,14 +1107,14 @@ xfs_file_iomap_end_delalloc(
>  	end_fsb = XFS_B_TO_FSB(mp, offset + length);
>  
>  	/*
> -	 * Trim back delalloc blocks if we didn't manage to write the whole
> -	 * range reserved.
> +	 * Trim delalloc blocks if they were allocated by this write and we
> +	 * didn't manage to write the whole range.
>  	 *
>  	 * We don't need to care about racing delalloc as we hold i_mutex
>  	 * across the reserve/allocate/unreserve calls. If there are delalloc
>  	 * blocks in the range, they are ours.
>  	 */
> -	if (start_fsb < end_fsb) {
> +	if ((iomap->flags & IOMAP_F_NEW) && start_fsb < end_fsb) {
>  		truncate_pagecache_range(VFS_I(ip), XFS_FSB_TO_B(mp, start_fsb),
>  					 XFS_FSB_TO_B(mp, end_fsb) - 1);
>  
> @@ -1131,7 +1144,7 @@ xfs_file_iomap_end(
>  {
>  	if ((flags & IOMAP_WRITE) && iomap->type == IOMAP_DELALLOC)
>  		return xfs_file_iomap_end_delalloc(XFS_I(inode), offset,
> -				length, written);
> +				length, written, iomap);
>  	return 0;
>  }
>  
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diff mbox

Patch

diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
index a9c66d47757a..f32d12cfa42a 100644
--- a/fs/xfs/libxfs/xfs_bmap.c
+++ b/fs/xfs/libxfs/xfs_bmap.c
@@ -4150,6 +4150,19 @@  xfs_bmapi_read(
 	return 0;
 }
 
+/*
+ * Add a delayed allocation extent to an inode. Blocks are reserved from the
+ * global pool and the extent inserted into the inode in-core extent tree.
+ *
+ * On entry, got refers to the first extent beyond the offset of the extent to
+ * allocate or eof is specified if no such extent exists. On return, got refers
+ * to the newly allocated portion of the extent, which may be a subset of actual
+ * entry in the inodes extent list if it has been merged.
+ * 
+ * This difference is useful for callers that must distinguish newly allocated
+ * blocks from preexisting delalloc blocks within the range of the allocation
+ * request (in order to properly handle buffered write failure, for example).
+ */
 int
 xfs_bmapi_reserve_delalloc(
 	struct xfs_inode	*ip,
@@ -4236,13 +4249,8 @@  xfs_bmapi_reserve_delalloc(
 	got->br_startblock = nullstartblock(indlen);
 	got->br_blockcount = alen;
 	got->br_state = XFS_EXT_NORM;
-	xfs_bmap_add_extent_hole_delay(ip, whichfork, lastx, got);
 
-	/*
-	 * Update our extent pointer, given that xfs_bmap_add_extent_hole_delay
-	 * might have merged it into one of the neighbouring ones.
-	 */
-	xfs_bmbt_get_all(xfs_iext_get_ext(ifp, *lastx), got);
+	xfs_bmap_add_extent_hole_delay(ip, whichfork, lastx, got);
 
 	/*
 	 * Tag the inode if blocks were preallocated. Note that COW fork
@@ -4254,10 +4262,6 @@  xfs_bmapi_reserve_delalloc(
 	if (whichfork == XFS_COW_FORK && (prealloc || aoff < off || alen > len))
 		xfs_inode_set_cowblocks_tag(ip);
 
-	ASSERT(got->br_startoff <= aoff);
-	ASSERT(got->br_startoff + got->br_blockcount >= aoff + alen);
-	ASSERT(isnullstartblock(got->br_startblock));
-	ASSERT(got->br_state == XFS_EXT_NORM);
 	return 0;
 
 out_unreserve_blocks:
diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
index 41662fb14e87..ce39d0143567 100644
--- a/fs/xfs/xfs_iomap.c
+++ b/fs/xfs/xfs_iomap.c
@@ -613,7 +613,8 @@  xfs_file_iomap_begin_delay(
 
 retry:
 	error = xfs_bmapi_reserve_delalloc(ip, XFS_DATA_FORK, offset_fsb,
-			end_fsb - offset_fsb, prealloc_blocks, &got, &idx, eof);
+			end_fsb - offset_fsb, prealloc_blocks, &got, &idx,
+			eof);
 	switch (error) {
 	case 0:
 		break;
@@ -630,6 +631,12 @@  xfs_file_iomap_begin_delay(
 		goto out_unlock;
 	}
 
+	/*
+	 * IOMAP_F_NEW controls whether we punch out delalloc blocks if the
+	 * write happens to fail, which means we can't combine newly allocated
+	 * blocks with preexisting delalloc blocks in the same iomap.
+	 */
+	iomap->flags = IOMAP_F_NEW;
 	trace_xfs_iomap_alloc(ip, offset, count, 0, &got);
 done:
 	if (isnullstartblock(got.br_startblock))
@@ -1071,16 +1078,22 @@  xfs_file_iomap_end_delalloc(
 	struct xfs_inode	*ip,
 	loff_t			offset,
 	loff_t			length,
-	ssize_t			written)
+	ssize_t			written,
+	struct iomap		*iomap)
 {
 	struct xfs_mount	*mp = ip->i_mount;
 	xfs_fileoff_t		start_fsb;
 	xfs_fileoff_t		end_fsb;
 	int			error = 0;
 
-	/* behave as if the write failed if drop writes is enabled */
-	if (xfs_mp_drop_writes(mp))
+	/*
+	 * Behave as if the write failed if drop writes is enabled. Set the NEW
+	 * flag to force delalloc cleanup.
+	 */
+	if (xfs_mp_drop_writes(mp)) {
+		iomap->flags |= IOMAP_F_NEW;
 		written = 0;
+	}
 
 	/*
 	 * start_fsb refers to the first unused block after a short write. If
@@ -1094,14 +1107,14 @@  xfs_file_iomap_end_delalloc(
 	end_fsb = XFS_B_TO_FSB(mp, offset + length);
 
 	/*
-	 * Trim back delalloc blocks if we didn't manage to write the whole
-	 * range reserved.
+	 * Trim delalloc blocks if they were allocated by this write and we
+	 * didn't manage to write the whole range.
 	 *
 	 * We don't need to care about racing delalloc as we hold i_mutex
 	 * across the reserve/allocate/unreserve calls. If there are delalloc
 	 * blocks in the range, they are ours.
 	 */
-	if (start_fsb < end_fsb) {
+	if ((iomap->flags & IOMAP_F_NEW) && start_fsb < end_fsb) {
 		truncate_pagecache_range(VFS_I(ip), XFS_FSB_TO_B(mp, start_fsb),
 					 XFS_FSB_TO_B(mp, end_fsb) - 1);
 
@@ -1131,7 +1144,7 @@  xfs_file_iomap_end(
 {
 	if ((flags & IOMAP_WRITE) && iomap->type == IOMAP_DELALLOC)
 		return xfs_file_iomap_end_delalloc(XFS_I(inode), offset,
-				length, written);
+				length, written, iomap);
 	return 0;
 }