}
}
-/* Create a CoW reservation for a range of blocks within a file. */
-static int
-__xfs_reflink_reserve_cow(
+/*
+ * Trim the passed in imap to the next shared/unshared extent boundary, and
+ * if imap->br_startoff points to a shared extent reserve space for it in the
+ * COW fork. In this case *shared is set to true, else to false.
+ *
+ * Note that imap will always contain the block numbers for the existing blocks
+ * in the data fork, as the upper layers need them for read-modify-write
+ * operations.
+ */
+int
+xfs_reflink_reserve_cow(
struct xfs_inode *ip,
- xfs_fileoff_t *offset_fsb,
- xfs_fileoff_t end_fsb,
- bool *skipped)
+ struct xfs_bmbt_irec *imap,
+ bool *shared)
{
- struct xfs_bmbt_irec got, prev, imap;
- xfs_fileoff_t orig_end_fsb;
- int nimaps, eof = 0, error = 0;
- bool shared = false, trimmed = false;
+ struct xfs_bmbt_irec got, prev;
+ xfs_fileoff_t end_fsb, orig_end_fsb;
+ int eof = 0, error = 0;
+ bool trimmed;
xfs_extnum_t idx;
xfs_extlen_t align;
- /* Already reserved? Skip the refcount btree access. */
- xfs_bmap_search_extents(ip, *offset_fsb, XFS_COW_FORK, &eof, &idx,
+ /*
+ * Search the COW fork extent list first. This serves two purposes:
+ * first this implement the speculative preallocation using cowextisze,
+ * so that we also unshared block adjacent to shared blocks instead
+ * of just the shared blocks themselves. Second the lookup in the
+ * extent list is generally faster than going out to the shared extent
+ * tree.
+ */
+ xfs_bmap_search_extents(ip, imap->br_startoff, XFS_COW_FORK, &eof, &idx,
&got, &prev);
- if (!eof && got.br_startoff <= *offset_fsb) {
- end_fsb = orig_end_fsb = got.br_startoff + got.br_blockcount;
- trace_xfs_reflink_cow_found(ip, &got);
- goto done;
- }
+ if (!eof && got.br_startoff <= imap->br_startoff) {
+ trace_xfs_reflink_cow_found(ip, imap);
+ xfs_trim_extent(imap, got.br_startoff, got.br_blockcount);
- /* Read extent from the source file. */
- nimaps = 1;
- error = xfs_bmapi_read(ip, *offset_fsb, end_fsb - *offset_fsb,
- &imap, &nimaps, 0);
- if (error)
- goto out_unlock;
- ASSERT(nimaps == 1);
+ *shared = true;
+ return 0;
+ }
/* Trim the mapping to the nearest shared extent boundary. */
- error = xfs_reflink_trim_around_shared(ip, &imap, &shared, &trimmed);
+ error = xfs_reflink_trim_around_shared(ip, imap, shared, &trimmed);
if (error)
- goto out_unlock;
-
- end_fsb = orig_end_fsb = imap.br_startoff + imap.br_blockcount;
+ return error;
/* Not shared? Just report the (potentially capped) extent. */
- if (!shared) {
- *skipped = true;
- goto done;
- }
+ if (!*shared)
+ return 0;
/*
* Fork all the shared blocks from our write offset until the end of
*/
error = xfs_qm_dqattach_locked(ip, 0);
if (error)
- goto out_unlock;
+ return error;
+
+ end_fsb = orig_end_fsb = imap->br_startoff + imap->br_blockcount;
align = xfs_eof_alignment(ip, xfs_get_cowextsz_hint(ip));
if (align)
end_fsb = roundup_64(end_fsb, align);
retry:
- error = xfs_bmapi_reserve_delalloc(ip, XFS_COW_FORK, *offset_fsb,
- end_fsb - *offset_fsb, &got,
- &prev, &idx, eof);
+ error = xfs_bmapi_reserve_delalloc(ip, XFS_COW_FORK, imap->br_startoff,
+ end_fsb - imap->br_startoff, &got, &prev, &idx, eof);
switch (error) {
case 0:
break;
case -ENOSPC:
case -EDQUOT:
/* retry without any preallocation */
- trace_xfs_reflink_cow_enospc(ip, &imap);
+ trace_xfs_reflink_cow_enospc(ip, imap);
if (end_fsb != orig_end_fsb) {
end_fsb = orig_end_fsb;
goto retry;
}
/*FALLTHRU*/
default:
- goto out_unlock;
+ return error;
}
if (end_fsb != orig_end_fsb)
xfs_inode_set_cowblocks_tag(ip);
trace_xfs_reflink_cow_alloc(ip, &got);
-done:
- *offset_fsb = end_fsb;
-out_unlock:
- return error;
-}
-
-/* Create a CoW reservation for part of a file. */
-int
-xfs_reflink_reserve_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, end_fsb;
- bool skipped = false;
- int error = 0;
-
- trace_xfs_reflink_reserve_cow_range(ip, offset, count);
-
- offset_fsb = XFS_B_TO_FSBT(mp, offset);
- end_fsb = XFS_B_TO_FSB(mp, offset + count);
-
- xfs_ilock(ip, XFS_ILOCK_EXCL);
- while (offset_fsb < end_fsb) {
- error = __xfs_reflink_reserve_cow(ip, &offset_fsb, end_fsb,
- &skipped);
- if (error) {
- trace_xfs_reflink_reserve_cow_range_error(ip, error,
- _RET_IP_);
- break;
- }
- }
- xfs_iunlock(ip, XFS_ILOCK_EXCL);
-
- return error;
+ return 0;
}
/* Allocate all CoW reservations covering a range of blocks in a file. */
struct xfs_defer_ops dfops;
struct xfs_trans *tp;
xfs_fsblock_t first_block;
- xfs_fileoff_t next_fsb;
int nimaps = 1, error;
- bool skipped = false;
+ bool shared;
xfs_defer_init(&dfops, &first_block);
xfs_ilock(ip, XFS_ILOCK_EXCL);
- next_fsb = *offset_fsb;
- error = __xfs_reflink_reserve_cow(ip, &next_fsb, end_fsb, &skipped);
+ /* Read extent from the source file. */
+ nimaps = 1;
+ error = xfs_bmapi_read(ip, *offset_fsb, end_fsb - *offset_fsb,
+ &imap, &nimaps, 0);
+ if (error)
+ goto out_unlock;
+ ASSERT(nimaps == 1);
+
+ error = xfs_reflink_reserve_cow(ip, &imap, &shared);
if (error)
goto out_trans_cancel;
- if (skipped) {
- *offset_fsb = next_fsb;
+ if (!shared) {
+ *offset_fsb = imap.br_startoff + imap.br_blockcount;
goto out_trans_cancel;
}
xfs_trans_ijoin(tp, ip, 0);
- error = xfs_bmapi_write(tp, ip, *offset_fsb, next_fsb - *offset_fsb,
+ error = xfs_bmapi_write(tp, ip, imap.br_startoff, imap.br_blockcount,
XFS_BMAPI_COWFORK, &first_block,
XFS_EXTENTADD_SPACE_RES(mp, XFS_DATA_FORK),
&imap, &nimaps, &dfops);
if (error)
goto out_trans_cancel;
- /* We might not have been able to map the whole delalloc extent */
- *offset_fsb = min(*offset_fsb + imap.br_blockcount, next_fsb);
-
error = xfs_defer_finish(&tp, &dfops, NULL);
if (error)
goto out_trans_cancel;
error = xfs_trans_commit(tp);
+ *offset_fsb = imap.br_startoff + imap.br_blockcount;
out_unlock:
xfs_iunlock(ip, XFS_ILOCK_EXCL);
return error;
projects / cascardo / linux.git / blobdiff