xfs: use iomap_dio_rw
Straight switch over to using iomap for direct I/O - we already have the
non-COW dio path in write_begin for DAX and files with extent size hints,
so nothing to add there. The COW path is ported over from the old
get_blocks version and a bit of a mess, but I have some work in progress
to make it look more like the buffered I/O COW path.
This gets rid of xfs_get_blocks_direct and the last caller of
xfs_get_blocks with the create flag set, so all that code can be removed.
Last but not least I've removed a comment in xfs_filemap_fault that
refers to xfs_get_blocks entirely instead of updating it - while the
reference is correct, the whole DAX fault path looks different than
the non-DAX one, so it seems rather pointless.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Jens Axboe <axboe@fb.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
index 15a83813..0d14742 100644
--- a/fs/xfs/xfs_iomap.c
+++ b/fs/xfs/xfs_iomap.c
@@ -950,6 +950,19 @@ static inline bool imap_needs_alloc(struct inode *inode,
(IS_DAX(inode) && ISUNWRITTEN(imap));
}
+static inline bool need_excl_ilock(struct xfs_inode *ip, unsigned flags)
+{
+ /*
+ * COW writes will allocate delalloc space, so we need to make sure
+ * to take the lock exclusively here.
+ */
+ if (xfs_is_reflink_inode(ip) && (flags & (IOMAP_WRITE | IOMAP_ZERO)))
+ return true;
+ if ((flags & IOMAP_DIRECT) && (flags & IOMAP_WRITE))
+ return true;
+ return false;
+}
+
static int
xfs_file_iomap_begin(
struct inode *inode,
@@ -969,18 +982,14 @@ xfs_file_iomap_begin(
if (XFS_FORCED_SHUTDOWN(mp))
return -EIO;
- if ((flags & IOMAP_WRITE) && !IS_DAX(inode) &&
- !xfs_get_extsz_hint(ip)) {
+ if (((flags & (IOMAP_WRITE | IOMAP_DIRECT)) == IOMAP_WRITE) &&
+ !IS_DAX(inode) && !xfs_get_extsz_hint(ip)) {
/* Reserve delalloc blocks for regular writeback. */
return xfs_file_iomap_begin_delay(inode, offset, length, flags,
iomap);
}
- /*
- * COW writes will allocate delalloc space, so we need to make sure
- * to take the lock exclusively here.
- */
- if ((flags & (IOMAP_WRITE | IOMAP_ZERO)) && xfs_is_reflink_inode(ip)) {
+ if (need_excl_ilock(ip, flags)) {
lockmode = XFS_ILOCK_EXCL;
xfs_ilock(ip, XFS_ILOCK_EXCL);
} else {
@@ -993,17 +1002,41 @@ xfs_file_iomap_begin(
offset_fsb = XFS_B_TO_FSBT(mp, offset);
end_fsb = XFS_B_TO_FSB(mp, offset + length);
+ if (xfs_is_reflink_inode(ip) &&
+ (flags & IOMAP_WRITE) && (flags & IOMAP_DIRECT)) {
+ shared = xfs_reflink_find_cow_mapping(ip, offset, &imap);
+ if (shared) {
+ xfs_iunlock(ip, lockmode);
+ goto alloc_done;
+ }
+ ASSERT(!isnullstartblock(imap.br_startblock));
+ }
+
error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb, &imap,
&nimaps, 0);
if (error)
goto out_unlock;
- if (flags & IOMAP_REPORT) {
+ if ((flags & IOMAP_REPORT) ||
+ (xfs_is_reflink_inode(ip) &&
+ (flags & IOMAP_WRITE) && (flags & IOMAP_DIRECT))) {
/* Trim the mapping to the nearest shared extent boundary. */
error = xfs_reflink_trim_around_shared(ip, &imap, &shared,
&trimmed);
if (error)
goto out_unlock;
+
+ /*
+ * We're here because we're trying to do a directio write to a
+ * region that isn't aligned to a filesystem block. If the
+ * extent is shared, fall back to buffered mode to handle the
+ * RMW.
+ */
+ if (!(flags & IOMAP_REPORT) && shared) {
+ trace_xfs_reflink_bounce_dio_write(ip, &imap);
+ error = -EREMCHG;
+ goto out_unlock;
+ }
}
if ((flags & (IOMAP_WRITE | IOMAP_ZERO)) && xfs_is_reflink_inode(ip)) {
@@ -1038,6 +1071,7 @@ xfs_file_iomap_begin(
if (error)
return error;
+alloc_done:
iomap->flags = IOMAP_F_NEW;
trace_xfs_iomap_alloc(ip, offset, length, 0, &imap);
} else {