Report shared extents through the iomap interface so that FIEMAP
reports shared blocks accurately.
Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
---
fs/xfs/xfs_iomap.c | 19 ++++++++++++---
fs/xfs/xfs_iomap.h | 2 +-
fs/xfs/xfs_pnfs.c | 2 +-
fs/xfs/xfs_reflink.c | 62 ++++++++++++++++++++++++++++++++++++++++++++++++++
fs/xfs/xfs_reflink.h | 3 ++
5 files changed, 82 insertions(+), 6 deletions(-)
diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
index 6065bde..130010a 100644
--- a/fs/xfs/xfs_iomap.c
+++ b/fs/xfs/xfs_iomap.c
@@ -987,10 +987,13 @@ void
xfs_bmbt_to_iomap(
struct xfs_inode *ip,
struct iomap *iomap,
- struct xfs_bmbt_irec *imap)
+ struct xfs_bmbt_irec *imap,
+ bool is_shared)
{
struct xfs_mount *mp = ip->i_mount;
+ if (is_shared)
+ iomap->flags |= IOMAP_F_SHARED;
if (imap->br_startblock == HOLESTARTBLOCK) {
iomap->blkno = IOMAP_NULL_BLOCK;
iomap->type = IOMAP_HOLE;
@@ -1028,6 +1031,7 @@ xfs_file_iomap_begin(
struct xfs_mount *mp = ip->i_mount;
struct xfs_bmbt_irec imap;
xfs_fileoff_t offset_fsb, end_fsb;
+ bool shared, trimmed;
int nimaps = 1, error = 0;
if (XFS_FORCED_SHUTDOWN(mp))
@@ -1053,7 +1057,14 @@ xfs_file_iomap_begin(
}
error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb, &imap,
- &nimaps, XFS_BMAPI_ENTIRE);
+ &nimaps, 0);
+ if (error) {
+ xfs_iunlock(ip, XFS_ILOCK_EXCL);
+ return error;
+ }
+
+ /* Trim the mapping to the nearest shared extent boundary. */
+ error = xfs_reflink_trim_around_shared(ip, &imap, &shared, &trimmed);
if (error) {
xfs_iunlock(ip, XFS_ILOCK_EXCL);
return error;
@@ -1095,7 +1106,7 @@ xfs_file_iomap_begin(
trace_xfs_iomap_found(ip, offset, length, 0, &imap);
}
- xfs_bmbt_to_iomap(ip, iomap, &imap);
+ xfs_bmbt_to_iomap(ip, iomap, &imap, shared);
return 0;
}
@@ -1193,7 +1204,7 @@ out_unlock:
if (!error) {
ASSERT(nimaps);
- xfs_bmbt_to_iomap(ip, iomap, &imap);
+ xfs_bmbt_to_iomap(ip, iomap, &imap, false);
}
return error;
diff --git a/fs/xfs/xfs_iomap.h b/fs/xfs/xfs_iomap.h
index 52f9c99..c04bf99 100644
--- a/fs/xfs/xfs_iomap.h
+++ b/fs/xfs/xfs_iomap.h
@@ -34,7 +34,7 @@ int xfs_iomap_cow_delay(struct xfs_inode *, xfs_off_t, size_t,
struct xfs_bmbt_irec *);
void xfs_bmbt_to_iomap(struct xfs_inode *, struct iomap *,
- struct xfs_bmbt_irec *);
+ struct xfs_bmbt_irec *, bool);
extern struct iomap_ops xfs_iomap_ops;
extern struct iomap_ops xfs_xattr_iomap_ops;
diff --git a/fs/xfs/xfs_pnfs.c b/fs/xfs/xfs_pnfs.c
index 93a7aaf..5519e4b 100644
--- a/fs/xfs/xfs_pnfs.c
+++ b/fs/xfs/xfs_pnfs.c
@@ -188,7 +188,7 @@ xfs_fs_map_blocks(
}
xfs_iunlock(ip, XFS_IOLOCK_EXCL);
- xfs_bmbt_to_iomap(ip, iomap, &imap);
+ xfs_bmbt_to_iomap(ip, iomap, &imap, false);
*device_generation = mp->m_generation;
return error;
out_unlock:
diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c
index 82d66a4..885ec61 100644
--- a/fs/xfs/xfs_reflink.c
+++ b/fs/xfs/xfs_reflink.c
@@ -179,6 +179,68 @@ xfs_reflink_find_shared(
return error;
}
+/*
+ * Trim the mapping to the next block where there's a change in the
+ * shared/unshared status. More specifically, this means that we
+ * find the lowest-numbered extent of shared blocks that coincides with
+ * the given block mapping. If the shared extent overlaps the start of
+ * the mapping, trim the mapping to the end of the shared extent. If
+ * the shared region intersects the mapping, trim the mapping to the
+ * start of the shared extent. If there are no shared regions that
+ * overlap, just return the original extent.
+ */
+int
+xfs_reflink_trim_around_shared(
+ struct xfs_inode *ip,
+ struct xfs_bmbt_irec *irec,
+ bool *shared,
+ bool *trimmed)
+{
+ xfs_agnumber_t agno;
+ xfs_agblock_t agbno;
+ xfs_extlen_t aglen;
+ xfs_agblock_t fbno;
+ xfs_extlen_t flen;
+ int error = 0;
+
+ /* Holes, unwritten, and delalloc extents cannot be shared */
+ if (!xfs_is_reflink_inode(ip) ||
+ ISUNWRITTEN(irec) ||
+ irec->br_startblock == HOLESTARTBLOCK ||
+ irec->br_startblock == DELAYSTARTBLOCK) {
+ *shared = false;
+ return 0;
+ }
+
+ trace_xfs_reflink_trim_around_shared(ip, irec);
+
+ agno = XFS_FSB_TO_AGNO(ip->i_mount, irec->br_startblock);
+ agbno = XFS_FSB_TO_AGBNO(ip->i_mount, irec->br_startblock);
+ aglen = irec->br_blockcount;
+
+ error = xfs_reflink_find_shared(ip->i_mount, agno, agbno,
+ aglen, &fbno, &flen, true);
+ if (error)
+ return error;
+
+ *shared = *trimmed = false;
+ if (flen == 0) {
+ /* No shared blocks at all. */
+ return 0;
+ } else if (fbno == agbno) {
+ /* The start of this extent is shared. */
+ irec->br_blockcount = flen;
+ *shared = true;
+ *trimmed = true;
+ return 0;
+ } else {
+ /* There's a shared extent midway through this extent. */
+ irec->br_blockcount = fbno - agbno;
+ *trimmed = true;
+ return 0;
+ }
+}
+
/* Find the shared ranges under an irec, and set up delalloc extents. */
static int
xfs_reflink_reserve_cow_extent(
diff --git a/fs/xfs/xfs_reflink.h b/fs/xfs/xfs_reflink.h
index 0ffabfb..e0bad68 100644
--- a/fs/xfs/xfs_reflink.h
+++ b/fs/xfs/xfs_reflink.h
@@ -23,6 +23,9 @@
extern int xfs_reflink_find_shared(struct xfs_mount *mp, xfs_agnumber_t agno,
xfs_agblock_t agbno, xfs_extlen_t aglen, xfs_agblock_t *fbno,
xfs_extlen_t *flen, bool find_maximal);
+extern int xfs_reflink_trim_around_shared(struct xfs_inode *ip,
+ struct xfs_bmbt_irec *irec, bool *shared, bool *trimmed);
+
extern int xfs_reflink_reserve_cow_range(struct xfs_inode *ip,
xfs_fileoff_t offset_fsb, xfs_fileoff_t end_fsb);
extern bool xfs_reflink_is_cow_pending(struct xfs_inode *ip, xfs_off_t offset);
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