[PATCH 19/43] xfs: enable CoW for realtime data

Darrick J. Wong
2024-12-13T01:15:12Z

From: Darrick J. Wong <djwong@kernel.org>

Update our write paths to support copy on write on the rt volume. This
works in more or less the same way as it does on the data device, with
the major exception that we never do delalloc on the rt volume.

Because we consider unwritten CoW fork staging extents to be incore
quota reservation, we update xfs_quota_reserve_blkres to support this
case. Though xfs doesn't allow rt and quota together, the change is
trivial and we shouldn't leave a logic bomb here.

Signed-off-by: "Darrick J. Wong" <djwong@kernel.org>
---
fs/xfs/xfs_reflink.c | 36 ++++++++++++++++++++++++++++--------
1 file changed, 28 insertions(+), 8 deletions(-)

diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c
index 29574b015fddc0..24f545687b8730 100644
--- a/fs/xfs/xfs_reflink.c
+++ b/fs/xfs/xfs_reflink.c
@@ -439,20 +439,26 @@ xfs_reflink_fill_cow_hole(
struct xfs_mount *mp = ip->i_mount;
struct xfs_trans *tp;
xfs_filblks_t resaligned;
- xfs_extlen_t resblks;
+ unsigned int dblocks = 0, rblocks = 0;
int nimaps;
int error;
bool found;

resaligned = xfs_aligned_fsb_count(imap->br_startoff,
imap->br_blockcount, xfs_get_cowextsz_hint(ip));
- resblks = XFS_DIOSTRAT_SPACE_RES(mp, resaligned);
+ if (XFS_IS_REALTIME_INODE(ip)) {
+ dblocks = XFS_DIOSTRAT_SPACE_RES(mp, 0);
+ rblocks = resaligned;
+ } else {
+ dblocks = XFS_DIOSTRAT_SPACE_RES(mp, resaligned);
+ rblocks = 0;
+ }

xfs_iunlock(ip, *lockmode);
*lockmode = 0;

- error = xfs_trans_alloc_inode(ip, &M_RES(mp)->tr_write, resblks, 0,
- false, &tp);
+ error = xfs_trans_alloc_inode(ip, &M_RES(mp)->tr_write, dblocks,
+ rblocks, false, &tp);
if (error)
return error;

@@ -1212,7 +1218,7 @@ xfs_reflink_remap_extent(
struct xfs_trans *tp;
xfs_off_t newlen;
int64_t qdelta = 0;
- unsigned int resblks;
+ unsigned int dblocks, rblocks, resblks;
bool quota_reserved = true;
bool smap_real;
bool dmap_written = xfs_bmap_is_written_extent(dmap);
@@ -1243,8 +1249,15 @@ xfs_reflink_remap_extent(
* we're remapping.
*/
resblks = XFS_EXTENTADD_SPACE_RES(mp, XFS_DATA_FORK);
+ if (XFS_IS_REALTIME_INODE(ip)) {
+ dblocks = resblks;
+ rblocks = dmap->br_blockcount;
+ } else {
+ dblocks = resblks + dmap->br_blockcount;
+ rblocks = 0;
+ }
error = xfs_trans_alloc_inode(ip, &M_RES(mp)->tr_write,
- resblks + dmap->br_blockcount, 0, false, &tp);
+ dblocks, rblocks, false, &tp);
if (error == -EDQUOT || error == -ENOSPC) {
quota_reserved = false;
error = xfs_trans_alloc_inode(ip, &M_RES(mp)->tr_write,
@@ -1324,8 +1337,15 @@ xfs_reflink_remap_extent(
* done.
*/
if (!quota_reserved && !smap_real && dmap_written) {
- error = xfs_trans_reserve_quota_nblks(tp, ip,
- dmap->br_blockcount, 0, false);
+ if (XFS_IS_REALTIME_INODE(ip)) {
+ dblocks = 0;
+ rblocks = dmap->br_blockcount;
+ } else {
+ dblocks = dmap->br_blockcount;
+ rblocks = 0;
+ }
+ error = xfs_trans_reserve_quota_nblks(tp, ip, dblocks, rblocks,
+ false);
if (error)
goto out_cancel;
}