[PATCH 6/9] xfs: simplify the xfs_iomap_write_direct calling conventions

Christoph Hellwig
2019-10-30T18:05:00Z

Move the EOF alignment and checking for the next allocated extent into
the callers to avoid the need to pass the byte based offset and count
as well as looking at the incoming imap. The added benefit is that
the caller can unlock the incoming ilock and the function doesn't have
funny unbalanced locking contexts.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
---
fs/xfs/xfs_iomap.c | 82 ++++++++++++++++------------------------------
fs/xfs/xfs_iomap.h | 6 ++--
fs/xfs/xfs_pnfs.c | 25 +++++++-------
3 files changed, 46 insertions(+), 67 deletions(-)

diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
index c21c4f7a7389..217eb44c1159 100644
--- a/fs/xfs/xfs_iomap.c
+++ b/fs/xfs/xfs_iomap.c
@@ -148,7 +148,7 @@ xfs_eof_alignment(
* Check if last_fsb is outside the last extent, and if so grow it to the next
* stripe unit boundary.
*/
-static xfs_fileoff_t
+xfs_fileoff_t
xfs_iomap_eof_align_last_fsb(
struct xfs_inode *ip,
xfs_fileoff_t end_fsb)
@@ -185,61 +185,36 @@ xfs_iomap_eof_align_last_fsb(

int
xfs_iomap_write_direct(
- xfs_inode_t *ip,
- xfs_off_t offset,
- size_t count,
- xfs_bmbt_irec_t *imap,
- int nmaps)
+ struct xfs_inode *ip,
+ xfs_fileoff_t offset_fsb,
+ xfs_fileoff_t count_fsb,
+ struct xfs_bmbt_irec *imap)
{
- xfs_mount_t *mp = ip->i_mount;
- xfs_fileoff_t offset_fsb = XFS_B_TO_FSBT(mp, offset);
- xfs_fileoff_t last_fsb = xfs_iomap_end_fsb(mp, offset, count);
- xfs_filblks_t count_fsb, resaligned;
- xfs_extlen_t extsz;
- int nimaps;
- int quota_flag;
- int rt;
- xfs_trans_t *tp;
- uint qblocks, resblks, resrtextents;
- int error;
- int lockmode;
- int bmapi_flags = XFS_BMAPI_PREALLOC;
- uint tflags = 0;
-
- rt = XFS_IS_REALTIME_INODE(ip);
- extsz = xfs_get_extsz_hint(ip);
- lockmode = XFS_ILOCK_SHARED; /* locked by caller */
-
- ASSERT(xfs_isilocked(ip, lockmode));
+ struct xfs_mount *mp = ip->i_mount;
+ struct xfs_trans *tp;
+ xfs_filblks_t resaligned;
+ int nimaps;
+ int quota_flag;
+ uint qblocks, resblks;
+ unsigned int resrtextents = 0;
+ int error;
+ int bmapi_flags = XFS_BMAPI_PREALLOC;
+ uint tflags = 0;

- if (offset + count > XFS_ISIZE(ip)) {
- last_fsb = xfs_iomap_eof_align_last_fsb(ip, last_fsb);
- } else {
- if (nmaps && (imap->br_startblock == HOLESTARTBLOCK))
- last_fsb = min(last_fsb, (xfs_fileoff_t)
- imap->br_blockcount +
- imap->br_startoff);
- }
- count_fsb = last_fsb - offset_fsb;
ASSERT(count_fsb > 0);
- resaligned = xfs_aligned_fsb_count(offset_fsb, count_fsb, extsz);

- if (unlikely(rt)) {
+ resaligned = xfs_aligned_fsb_count(offset_fsb, count_fsb,
+ xfs_get_extsz_hint(ip));
+ if (unlikely(XFS_IS_REALTIME_INODE(ip))) {
resrtextents = qblocks = resaligned;
resrtextents /= mp->m_sb.sb_rextsize;
resblks = XFS_DIOSTRAT_SPACE_RES(mp, 0);
quota_flag = XFS_QMOPT_RES_RTBLKS;
} else {
- resrtextents = 0;
resblks = qblocks = XFS_DIOSTRAT_SPACE_RES(mp, resaligned);
quota_flag = XFS_QMOPT_RES_REGBLKS;
}

- /*
- * Drop the shared lock acquired by the caller, attach the dquot if
- * necessary and move on to transaction setup.
- */
- xfs_iunlock(ip, lockmode);
error = xfs_qm_dqattach(ip);
if (error)
return error;
@@ -269,8 +244,7 @@ xfs_iomap_write_direct(
if (error)
return error;

- lockmode = XFS_ILOCK_EXCL;
- xfs_ilock(ip, lockmode);
+ xfs_ilock(ip, XFS_ILOCK_EXCL);

error = xfs_trans_reserve_quota_nblks(tp, ip, qblocks, 0, quota_flag);
if (error)
@@ -307,7 +281,7 @@ xfs_iomap_write_direct(
error = xfs_alert_fsblock_zero(ip, imap);

out_unlock:
- xfs_iunlock(ip, lockmode);
+ xfs_iunlock(ip, XFS_ILOCK_EXCL);
return error;

out_res_cancel:
@@ -807,14 +781,16 @@ xfs_direct_write_iomap_begin(
* lower level functions are updated.
*/
length = min_t(loff_t, length, 1024 * PAGE_SIZE);
+ end_fsb = xfs_iomap_end_fsb(mp, offset, length);

- /*
- * xfs_iomap_write_direct() expects the shared lock. It is unlocked on
- * return.
- */
- if (lockmode == XFS_ILOCK_EXCL)
- xfs_ilock_demote(ip, lockmode);
- error = xfs_iomap_write_direct(ip, offset, length, &imap, nimaps);
+ if (offset + length > XFS_ISIZE(ip))
+ end_fsb = xfs_iomap_eof_align_last_fsb(ip, end_fsb);
+ else if (nimaps && imap.br_startblock == HOLESTARTBLOCK)
+ end_fsb = min(end_fsb, imap.br_startoff + imap.br_blockcount);
+ xfs_iunlock(ip, lockmode);
+
+ error = xfs_iomap_write_direct(ip, offset_fsb, end_fsb - offset_fsb,
+ &imap);
if (error)
return error;

diff --git a/fs/xfs/xfs_iomap.h b/fs/xfs/xfs_iomap.h
index d5b292bdaf82..7d3703556d0e 100644
--- a/fs/xfs/xfs_iomap.h
+++ b/fs/xfs/xfs_iomap.h
@@ -11,9 +11,11 @@
struct xfs_inode;
struct xfs_bmbt_irec;

-int xfs_iomap_write_direct(struct xfs_inode *, xfs_off_t, size_t,
- struct xfs_bmbt_irec *, int);
+int xfs_iomap_write_direct(struct xfs_inode *ip, xfs_fileoff_t offset_fsb,
+ xfs_fileoff_t count_fsb, struct xfs_bmbt_irec *imap);
int xfs_iomap_write_unwritten(struct xfs_inode *, xfs_off_t, xfs_off_t, bool);
+xfs_fileoff_t xfs_iomap_eof_align_last_fsb(struct xfs_inode *ip,
+ xfs_fileoff_t end_fsb);

int xfs_bmbt_to_iomap(struct xfs_inode *, struct iomap *,
struct xfs_bmbt_irec *, u16);
diff --git a/fs/xfs/xfs_pnfs.c b/fs/xfs/xfs_pnfs.c
index ada46e9f5ff1..ae3f00cb6a43 100644
--- a/fs/xfs/xfs_pnfs.c
+++ b/fs/xfs/xfs_pnfs.c
@@ -143,21 +143,20 @@ xfs_fs_map_blocks(
lock_flags = xfs_ilock_data_map_shared(ip);
error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb,
&imap, &nimaps, bmapi_flags);
- xfs_iunlock(ip, lock_flags);
-
- if (error)
- goto out_unlock;

ASSERT(!nimaps || imap.br_startblock != DELAYSTARTBLOCK);

- if (write && (!nimaps || imap.br_startblock == HOLESTARTBLOCK)) {
- /*
- * xfs_iomap_write_direct() expects to take ownership of the
- * shared ilock.
- */
- xfs_ilock(ip, XFS_ILOCK_SHARED);
- error = xfs_iomap_write_direct(ip, offset, length, &imap,
- nimaps);
+ if (!error && write &&
+ (!nimaps || imap.br_startblock == HOLESTARTBLOCK)) {
+ if (offset + length > XFS_ISIZE(ip))
+ end_fsb = xfs_iomap_eof_align_last_fsb(ip, end_fsb);
+ else if (nimaps && imap.br_startblock == HOLESTARTBLOCK)
+ end_fsb = min(end_fsb, imap.br_startoff +
+ imap.br_blockcount);
+ xfs_iunlock(ip, lock_flags);
+
+ error = xfs_iomap_write_direct(ip, offset_fsb,
+ end_fsb - offset_fsb, &imap);
if (error)
goto out_unlock;

@@ -170,6 +169,8 @@ xfs_fs_map_blocks(
XFS_PREALLOC_SET | XFS_PREALLOC_SYNC);
if (error)
goto out_unlock;
+ } else {
+ xfs_iunlock(ip, lock_flags);
}
xfs_iunlock(ip, XFS_IOLOCK_EXCL);

--
2.20.1