[PATCH 36/36] xfs: convert trim to use for_each_perag_range

Dave Chinner
2021-12-03T00:01:23Z

To convert it to using active perag references and hence make it
shrink safe.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
fs/xfs/xfs_discard.c | 50 ++++++++++++++++++++------------------------
1 file changed, 23 insertions(+), 27 deletions(-)

diff --git a/fs/xfs/xfs_discard.c b/fs/xfs/xfs_discard.c
index ccec28c914cd..310d760376a5 100644
--- a/fs/xfs/xfs_discard.c
+++ b/fs/xfs/xfs_discard.c
@@ -21,23 +21,20 @@

STATIC int
xfs_trim_extents(
- struct xfs_mount *mp,
- xfs_agnumber_t agno,
+ struct xfs_perag *pag,
xfs_daddr_t start,
xfs_daddr_t end,
xfs_daddr_t minlen,
uint64_t *blocks_trimmed)
{
+ struct xfs_mount *mp = pag->pag_mount;
struct block_device *bdev = mp->m_ddev_targp->bt_bdev;
struct xfs_btree_cur *cur;
struct xfs_buf *agbp;
struct xfs_agf *agf;
- struct xfs_perag *pag;
int error;
int i;

- pag = xfs_perag_get(mp, agno);
-
/*
* Force out the log. This means any transactions that might have freed
* space before we take the AGF buffer lock are now on disk, and the
@@ -47,7 +44,7 @@ xfs_trim_extents(

error = xfs_alloc_read_agf(pag, NULL, 0, &agbp);
if (error)
- goto out_put_perag;
+ return error;
agf = agbp->b_addr;

cur = xfs_allocbt_init_cursor(mp, NULL, agbp, pag, XFS_BTNUM_CNT);
@@ -71,10 +68,10 @@ xfs_trim_extents(

error = xfs_alloc_get_rec(cur, &fbno, &flen, &i);
if (error)
- goto out_del_cursor;
+ break;
if (XFS_IS_CORRUPT(mp, i != 1)) {
error = -EFSCORRUPTED;
- goto out_del_cursor;
+ break;
}
ASSERT(flen <= be32_to_cpu(agf->agf_longest));

@@ -83,15 +80,15 @@ xfs_trim_extents(
* the format the range/len variables are supplied in by
* userspace.
*/
- dbno = XFS_AGB_TO_DADDR(mp, agno, fbno);
+ dbno = XFS_AGB_TO_DADDR(mp, pag->pag_agno, fbno);
dlen = XFS_FSB_TO_BB(mp, flen);

/*
* Too small? Give up.
*/
if (dlen < minlen) {
- trace_xfs_discard_toosmall(mp, agno, fbno, flen);
- goto out_del_cursor;
+ trace_xfs_discard_toosmall(mp, pag->pag_agno, fbno, flen);
+ break;
}

/*
@@ -100,7 +97,7 @@ xfs_trim_extents(
* down partially overlapping ranges for now.
*/
if (dbno + dlen < start || dbno > end) {
- trace_xfs_discard_exclude(mp, agno, fbno, flen);
+ trace_xfs_discard_exclude(mp, pag->pag_agno, fbno, flen);
goto next_extent;
}

@@ -109,32 +106,30 @@ xfs_trim_extents(
* discard and try again the next time.
*/
if (xfs_extent_busy_search(mp, pag, fbno, flen)) {
- trace_xfs_discard_busy(mp, agno, fbno, flen);
+ trace_xfs_discard_busy(mp, pag->pag_agno, fbno, flen);
goto next_extent;
}

- trace_xfs_discard_extent(mp, agno, fbno, flen);
+ trace_xfs_discard_extent(mp, pag->pag_agno, fbno, flen);
error = blkdev_issue_discard(bdev, dbno, dlen, GFP_NOFS, 0);
if (error)
- goto out_del_cursor;
+ break;
*blocks_trimmed += flen;

next_extent:
error = xfs_btree_decrement(cur, 0, &i);
if (error)
- goto out_del_cursor;
+ break;

if (fatal_signal_pending(current)) {
error = -ERESTARTSYS;
- goto out_del_cursor;
+ break;
}
}

out_del_cursor:
xfs_btree_del_cursor(cur, error);
xfs_buf_relse(agbp);
-out_put_perag:
- xfs_perag_put(pag);
return error;
}

@@ -152,11 +147,12 @@ xfs_ioc_trim(
struct xfs_mount *mp,
struct fstrim_range __user *urange)
{
+ struct xfs_perag *pag;
struct request_queue *q = bdev_get_queue(mp->m_ddev_targp->bt_bdev);
unsigned int granularity = q->limits.discard_granularity;
struct fstrim_range range;
xfs_daddr_t start, end, minlen;
- xfs_agnumber_t start_agno, end_agno, agno;
+ xfs_agnumber_t agno;
uint64_t blocks_trimmed = 0;
int error, last_error = 0;

@@ -193,18 +189,18 @@ xfs_ioc_trim(
end = start + BTOBBT(range.len) - 1;

if (end > XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks) - 1)
- end = XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks)- 1;
-
- start_agno = xfs_daddr_to_agno(mp, start);
- end_agno = xfs_daddr_to_agno(mp, end);
+ end = XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks) - 1;

- for (agno = start_agno; agno <= end_agno; agno++) {
- error = xfs_trim_extents(mp, agno, start, end, minlen,
+ agno = xfs_daddr_to_agno(mp, start);
+ for_each_perag_range(mp, agno, xfs_daddr_to_agno(mp, end), pag) {
+ error = xfs_trim_extents(pag, start, end, minlen,
&blocks_trimmed);
if (error) {
last_error = error;
- if (error == -ERESTARTSYS)
+ if (error == -ERESTARTSYS) {
+ xfs_perag_rele(pag);
break;
+ }
}
}

--
2.33.0