[PATCH v3 3/9] xfs: make xfs_bmapi_convert_delalloc() to allocate the target offset

From: Zhang Yi
Date: Mon Mar 18 2024 - 21:37:35 EST


From: Zhang Yi <yi.zhang@xxxxxxxxxx>

Since xfs_bmapi_convert_delalloc() only attempts to allocate the entire
delalloc extent and require multiple invocations to allocate the target
offset. So xfs_convert_blocks() add a loop to do this job and we call it
in the write back path, but xfs_convert_blocks() isn't a common helper.
Let's do it in xfs_bmapi_convert_delalloc() and drop
xfs_convert_blocks(), preparing for the post EOF delalloc blocks
converting in the buffered write begin path.

Signed-off-by: Zhang Yi <yi.zhang@xxxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
---
fs/xfs/libxfs/xfs_bmap.c | 34 +++++++++++++++++++++++--
fs/xfs/xfs_aops.c | 54 +++++++++++-----------------------------
2 files changed, 46 insertions(+), 42 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
index 07dc35de8ce5..042e8d3ab0ba 100644
--- a/fs/xfs/libxfs/xfs_bmap.c
+++ b/fs/xfs/libxfs/xfs_bmap.c
@@ -4516,8 +4516,8 @@ xfs_bmapi_write(
* invocations to allocate the target offset if a large enough physical extent
* is not available.
*/
-int
-xfs_bmapi_convert_delalloc(
+static int
+__xfs_bmapi_convert_delalloc(
struct xfs_inode *ip,
int whichfork,
xfs_off_t offset,
@@ -4648,6 +4648,36 @@ xfs_bmapi_convert_delalloc(
return error;
}

+/*
+ * Pass in a dellalloc extent and convert it to real extents, return the real
+ * extent that maps offset_fsb in iomap.
+ */
+int
+xfs_bmapi_convert_delalloc(
+ struct xfs_inode *ip,
+ int whichfork,
+ loff_t offset,
+ struct iomap *iomap,
+ unsigned int *seq)
+{
+ int error;
+
+ /*
+ * Attempt to allocate whatever delalloc extent currently backs offset
+ * and put the result into iomap. Allocate in a loop because it may
+ * take several attempts to allocate real blocks for a contiguous
+ * delalloc extent if free space is sufficiently fragmented.
+ */
+ do {
+ error = __xfs_bmapi_convert_delalloc(ip, whichfork, offset,
+ iomap, seq);
+ if (error)
+ return error;
+ } while (iomap->offset + iomap->length <= offset);
+
+ return 0;
+}
+
int
xfs_bmapi_remap(
struct xfs_trans *tp,
diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
index 813f85156b0c..6479e0dac69d 100644
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -233,45 +233,6 @@ xfs_imap_valid(
return true;
}

-/*
- * Pass in a dellalloc extent and convert it to real extents, return the real
- * extent that maps offset_fsb in wpc->iomap.
- *
- * The current page is held locked so nothing could have removed the block
- * backing offset_fsb, although it could have moved from the COW to the data
- * fork by another thread.
- */
-static int
-xfs_convert_blocks(
- struct iomap_writepage_ctx *wpc,
- struct xfs_inode *ip,
- int whichfork,
- loff_t offset)
-{
- int error;
- unsigned *seq;
-
- if (whichfork == XFS_COW_FORK)
- seq = &XFS_WPC(wpc)->cow_seq;
- else
- seq = &XFS_WPC(wpc)->data_seq;
-
- /*
- * Attempt to allocate whatever delalloc extent currently backs offset
- * and put the result into wpc->iomap. Allocate in a loop because it
- * may take several attempts to allocate real blocks for a contiguous
- * delalloc extent if free space is sufficiently fragmented.
- */
- do {
- error = xfs_bmapi_convert_delalloc(ip, whichfork, offset,
- &wpc->iomap, seq);
- if (error)
- return error;
- } while (wpc->iomap.offset + wpc->iomap.length <= offset);
-
- return 0;
-}
-
static int
xfs_map_blocks(
struct iomap_writepage_ctx *wpc,
@@ -289,6 +250,7 @@ xfs_map_blocks(
struct xfs_iext_cursor icur;
int retries = 0;
int error = 0;
+ unsigned int *seq;

if (xfs_is_shutdown(mp))
return -EIO;
@@ -386,7 +348,19 @@ xfs_map_blocks(
trace_xfs_map_blocks_found(ip, offset, count, whichfork, &imap);
return 0;
allocate_blocks:
- error = xfs_convert_blocks(wpc, ip, whichfork, offset);
+ /*
+ * Convert a dellalloc extent to a real one. The current page is held
+ * locked so nothing could have removed the block backing offset_fsb,
+ * although it could have moved from the COW to the data fork by another
+ * thread.
+ */
+ if (whichfork == XFS_COW_FORK)
+ seq = &XFS_WPC(wpc)->cow_seq;
+ else
+ seq = &XFS_WPC(wpc)->data_seq;
+
+ error = xfs_bmapi_convert_delalloc(ip, whichfork, offset,
+ &wpc->iomap, seq);
if (error) {
/*
* If we failed to find the extent in the COW fork we might have
--
2.39.2