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xfs: allocate direct I/O COW blocks in iomap_begin
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Instead of preallocating all the required COW blocks in the high-level
write code do it inside the iomap code, like we do for all other I/O.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
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Christoph Hellwig authored and Darrick J. Wong committed Feb 7, 2017
1 parent a14234c commit 3c68d44
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Showing 5 changed files with 68 additions and 123 deletions.
8 changes: 0 additions & 8 deletions fs/xfs/xfs_file.c
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Original file line number Diff line number Diff line change
Expand Up @@ -561,14 +561,6 @@ xfs_file_dio_aio_write(
}

trace_xfs_file_direct_write(ip, count, iocb->ki_pos);

/* If this is a block-aligned directio CoW, remap immediately. */
if (xfs_is_reflink_inode(ip) && !unaligned_io) {
ret = xfs_reflink_allocate_cow_range(ip, iocb->ki_pos, count);
if (ret)
goto out;
}

ret = iomap_dio_rw(iocb, from, &xfs_iomap_ops, xfs_dio_write_end_io);
out:
xfs_iunlock(ip, iolock);
Expand Down
31 changes: 12 additions & 19 deletions fs/xfs/xfs_iomap.c
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Original file line number Diff line number Diff line change
Expand Up @@ -995,37 +995,31 @@ 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) ||
(xfs_is_reflink_inode(ip) &&
(flags & IOMAP_WRITE) && (flags & IOMAP_DIRECT))) {
if (flags & IOMAP_REPORT) {
/* Trim the mapping to the nearest shared extent boundary. */
error = xfs_reflink_trim_around_shared(ip, &imap, &shared,
&trimmed);
if (error)
goto out_unlock;

ASSERT((flags & IOMAP_REPORT) || !shared);
}

if ((flags & (IOMAP_WRITE | IOMAP_ZERO)) && xfs_is_reflink_inode(ip)) {
error = xfs_reflink_reserve_cow(ip, &imap, &shared);
if (error)
goto out_unlock;
if (flags & IOMAP_DIRECT) {
/* may drop and re-acquire the ilock */
error = xfs_reflink_allocate_cow(ip, &imap, &shared,
&lockmode);
if (error)
goto out_unlock;
} else {
error = xfs_reflink_reserve_cow(ip, &imap, &shared);
if (error)
goto out_unlock;
}

end_fsb = imap.br_startoff + imap.br_blockcount;
length = XFS_FSB_TO_B(mp, end_fsb) - offset;
Expand Down Expand Up @@ -1054,7 +1048,6 @@ 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 {
Expand Down
146 changes: 54 additions & 92 deletions fs/xfs/xfs_reflink.c
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Original file line number Diff line number Diff line change
Expand Up @@ -382,84 +382,85 @@ xfs_reflink_convert_cow(
}

/* Allocate all CoW reservations covering a range of blocks in a file. */
static int
__xfs_reflink_allocate_cow(
int
xfs_reflink_allocate_cow(
struct xfs_inode *ip,
xfs_fileoff_t *offset_fsb,
xfs_fileoff_t end_fsb)
struct xfs_bmbt_irec *imap,
bool *shared,
uint *lockmode)
{
struct xfs_mount *mp = ip->i_mount;
struct xfs_bmbt_irec imap, got;
xfs_fileoff_t offset_fsb = imap->br_startoff;
xfs_filblks_t count_fsb = imap->br_blockcount;
struct xfs_bmbt_irec got;
struct xfs_defer_ops dfops;
struct xfs_trans *tp;
struct xfs_trans *tp = NULL;
xfs_fsblock_t first_block;
int nimaps, error, lockmode;
bool shared, trimmed;
int nimaps, error = 0;
bool trimmed;
xfs_filblks_t resaligned;
xfs_extlen_t resblks;
xfs_extlen_t resblks = 0;
xfs_extnum_t idx;

resaligned = xfs_aligned_fsb_count(*offset_fsb, end_fsb - *offset_fsb,
xfs_get_cowextsz_hint(ip));
resblks = XFS_DIOSTRAT_SPACE_RES(mp, resaligned);

error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, resblks, 0, 0, &tp);
if (error)
return error;

lockmode = XFS_ILOCK_EXCL;
xfs_ilock(ip, lockmode);
retry:
ASSERT(xfs_is_reflink_inode(ip));
ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL | XFS_ILOCK_SHARED));

/*
* Even if the extent is not shared we might have a preallocation for
* it in the COW fork. If so use it.
*/
if (xfs_iext_lookup_extent(ip, ip->i_cowfp, *offset_fsb, &idx, &got) &&
got.br_startoff <= *offset_fsb) {
if (xfs_iext_lookup_extent(ip, ip->i_cowfp, offset_fsb, &idx, &got) &&
got.br_startoff <= offset_fsb) {
*shared = true;

/* If we have a real allocation in the COW fork we're done. */
if (!isnullstartblock(got.br_startblock)) {
xfs_trim_extent(&got, *offset_fsb,
end_fsb - *offset_fsb);
*offset_fsb = got.br_startoff + got.br_blockcount;
goto out_trans_cancel;
xfs_trim_extent(&got, offset_fsb, count_fsb);
*imap = got;
goto convert;
}

xfs_trim_extent(imap, got.br_startoff, got.br_blockcount);
} else {
nimaps = 1;
error = xfs_bmapi_read(ip, *offset_fsb, end_fsb - *offset_fsb,
&imap, &nimaps, 0);
if (error)
goto out_trans_cancel;
ASSERT(nimaps == 1);
error = xfs_reflink_trim_around_shared(ip, imap, shared, &trimmed);
if (error || !*shared)
goto out;
}

/* Trim the mapping to the nearest shared extent boundary. */
error = xfs_reflink_trim_around_shared(ip, &imap, &shared,
&trimmed);
if (error)
goto out_trans_cancel;
if (!tp) {
resaligned = xfs_aligned_fsb_count(imap->br_startoff,
imap->br_blockcount, xfs_get_cowextsz_hint(ip));
resblks = XFS_DIOSTRAT_SPACE_RES(mp, resaligned);

if (!shared) {
*offset_fsb = imap.br_startoff + imap.br_blockcount;
goto out_trans_cancel;
}
xfs_iunlock(ip, *lockmode);
error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, resblks, 0, 0, &tp);
*lockmode = XFS_ILOCK_EXCL;
xfs_ilock(ip, *lockmode);

*offset_fsb = imap.br_startoff;
end_fsb = imap.br_startoff + imap.br_blockcount;
if (error)
return error;

error = xfs_qm_dqattach_locked(ip, 0);
if (error)
goto out;
goto retry;
}

error = xfs_trans_reserve_quota_nblks(tp, ip, resblks, 0,
XFS_QMOPT_RES_REGBLKS);
if (error)
goto out_trans_cancel;
goto out;

xfs_trans_ijoin(tp, ip, 0);

xfs_defer_init(&dfops, &first_block);
nimaps = 1;

/* Allocate the entire reservation as unwritten blocks. */
error = xfs_bmapi_write(tp, ip, *offset_fsb, end_fsb - *offset_fsb,
error = xfs_bmapi_write(tp, ip, imap->br_startoff, imap->br_blockcount,
XFS_BMAPI_COWFORK | XFS_BMAPI_PREALLOC, &first_block,
resblks, &imap, &nimaps, &dfops);
resblks, imap, &nimaps, &dfops);
if (error)
goto out_bmap_cancel;

Expand All @@ -470,57 +471,18 @@ __xfs_reflink_allocate_cow(

error = xfs_trans_commit(tp);
if (error)
goto out_unlock;

*offset_fsb = imap.br_startoff + imap.br_blockcount;

out_unlock:
xfs_iunlock(ip, lockmode);
return error;

return error;
convert:
return xfs_reflink_convert_cow_extent(ip, imap, offset_fsb, count_fsb,
&dfops);
out_bmap_cancel:
xfs_defer_cancel(&dfops);
xfs_trans_unreserve_quota_nblks(tp, ip, (long)resblks, 0,
XFS_QMOPT_RES_REGBLKS);
out_trans_cancel:
xfs_trans_cancel(tp);
goto out_unlock;
}

/* Allocate all CoW reservations covering a part of a file. */
int
xfs_reflink_allocate_cow_range(
struct xfs_inode *ip,
xfs_off_t offset,
xfs_off_t count)
{
struct xfs_mount *mp = ip->i_mount;
xfs_fileoff_t offset_fsb = XFS_B_TO_FSBT(mp, offset);
xfs_fileoff_t end_fsb = XFS_B_TO_FSB(mp, offset + count);
int error;

ASSERT(xfs_is_reflink_inode(ip));

trace_xfs_reflink_allocate_cow_range(ip, offset, count);

/*
* Make sure that the dquots are there.
*/
error = xfs_qm_dqattach(ip, 0);
if (error)
return error;

while (offset_fsb < end_fsb) {
error = __xfs_reflink_allocate_cow(ip, &offset_fsb, end_fsb);
if (error) {
trace_xfs_reflink_allocate_cow_range_error(ip, error,
_RET_IP_);
return error;
}
}

/* Convert the CoW extents to regular. */
return xfs_reflink_convert_cow(ip, offset, count);
out:
if (tp)
xfs_trans_cancel(tp);
return error;
}

/*
Expand Down
4 changes: 2 additions & 2 deletions fs/xfs/xfs_reflink.h
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Original file line number Diff line number Diff line change
Expand Up @@ -28,8 +28,8 @@ extern int xfs_reflink_trim_around_shared(struct xfs_inode *ip,

extern int xfs_reflink_reserve_cow(struct xfs_inode *ip,
struct xfs_bmbt_irec *imap, bool *shared);
extern int xfs_reflink_allocate_cow_range(struct xfs_inode *ip,
xfs_off_t offset, xfs_off_t count);
extern int xfs_reflink_allocate_cow(struct xfs_inode *ip,
struct xfs_bmbt_irec *imap, bool *shared, uint *lockmode);
extern int xfs_reflink_convert_cow(struct xfs_inode *ip, xfs_off_t offset,
xfs_off_t count);
extern bool xfs_reflink_find_cow_mapping(struct xfs_inode *ip, xfs_off_t offset,
Expand Down
2 changes: 0 additions & 2 deletions fs/xfs/xfs_trace.h
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Original file line number Diff line number Diff line change
Expand Up @@ -3247,7 +3247,6 @@ DEFINE_INODE_IREC_EVENT(xfs_reflink_cow_enospc);
DEFINE_INODE_IREC_EVENT(xfs_reflink_convert_cow);

DEFINE_RW_EVENT(xfs_reflink_reserve_cow);
DEFINE_RW_EVENT(xfs_reflink_allocate_cow_range);

DEFINE_SIMPLE_IO_EVENT(xfs_reflink_bounce_dio_write);
DEFINE_IOMAP_EVENT(xfs_reflink_find_cow_mapping);
Expand All @@ -3257,7 +3256,6 @@ DEFINE_SIMPLE_IO_EVENT(xfs_reflink_cancel_cow_range);
DEFINE_SIMPLE_IO_EVENT(xfs_reflink_end_cow);
DEFINE_INODE_IREC_EVENT(xfs_reflink_cow_remap);

DEFINE_INODE_ERROR_EVENT(xfs_reflink_allocate_cow_range_error);
DEFINE_INODE_ERROR_EVENT(xfs_reflink_cancel_cow_range_error);
DEFINE_INODE_ERROR_EVENT(xfs_reflink_end_cow_error);

Expand Down

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