Teach the bmap routine to know how to map a range of file blocks to a
specific range of physical blocks, instead of simply allocating fresh
blocks. This enables reflink to map a file to blocks that are already
in use.
Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
---
fs/xfs/libxfs/xfs_bmap.c | 21 +++++++++++++++++++++
fs/xfs/libxfs/xfs_bmap.h | 3 +++
2 files changed, 24 insertions(+)
diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
index dfdd9e6..1297b94 100644
--- a/fs/xfs/libxfs/xfs_bmap.c
+++ b/fs/xfs/libxfs/xfs_bmap.c
@@ -3897,6 +3897,15 @@ STATIC int
xfs_bmap_alloc(
struct xfs_bmalloca *ap) /* bmap alloc argument struct */
{
+ if (ap->flags & XFS_BMAPI_EXACT) {
+ trace_xfs_reflink_relink_blocks(ap->ip, *ap->firstblock,
+ ap->length);
+ ap->blkno = *ap->firstblock;
+ ap->ip->i_d.di_nblocks += ap->length;
+ xfs_trans_log_inode(ap->tp, ap->ip, XFS_ILOG_CORE);
+ return 0;
+ }
+
if (XFS_IS_REALTIME_INODE(ap->ip) && ap->userdata)
return xfs_bmap_rtalloc(ap);
return xfs_bmap_btalloc(ap);
@@ -4519,6 +4528,12 @@ xfs_bmapi_write(
ASSERT(len > 0);
ASSERT(XFS_IFORK_FORMAT(ip, whichfork) != XFS_DINODE_FMT_LOCAL);
ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
+ if (whichfork == XFS_ATTR_FORK)
+ ASSERT(!(flags & XFS_BMAPI_EXACT));
+ if (flags & XFS_BMAPI_EXACT) {
+ ASSERT(!(flags & XFS_BMAPI_PREALLOC));
+ ASSERT(!(flags & XFS_BMAPI_CONVERT));
+ }
if (unlikely(XFS_TEST_ERROR(
(XFS_IFORK_FORMAT(ip, whichfork) != XFS_DINODE_FMT_EXTENTS &&
@@ -4568,6 +4583,12 @@ xfs_bmapi_write(
wasdelay = !inhole && isnullstartblock(bma.got.br_startblock);
/*
+ * Make sure we only reflink into a hole.
+ */
+ if (flags & XFS_BMAPI_EXACT)
+ ASSERT(inhole);
+
+ /*
* First, deal with the hole before the allocated space
* that we found, if any.
*/
diff --git a/fs/xfs/libxfs/xfs_bmap.h b/fs/xfs/libxfs/xfs_bmap.h
index 674819f..34db107 100644
--- a/fs/xfs/libxfs/xfs_bmap.h
+++ b/fs/xfs/libxfs/xfs_bmap.h
@@ -110,6 +110,9 @@ typedef struct xfs_bmap_free
*/
#define XFS_BMAPI_CONVERT 0x040
+#define XFS_BMAPI_EXACT 0x080 /* Map the inode offset to the block */
+ /* ap->firstblock. Used for reflink. */
+
#define XFS_BMAPI_FLAGS \
{ XFS_BMAPI_ENTIRE, "ENTIRE" }, \
{ XFS_BMAPI_METADATA, "METADATA" }, \
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