From 4862cfe825c0087c14452b362e708a35da675f5e Mon Sep 17 00:00:00 2001 From: "Darrick J. Wong" Date: Mon, 3 Oct 2016 09:11:35 -0700 Subject: [PATCH] xfs: support removing extents from CoW fork Create a helper method to remove extents from the CoW fork without any of the side effects (rmapbt/bmbt updates) of the regular extent deletion routine. We'll eventually use this to clear out the CoW fork during ioend processing. Signed-off-by: Darrick J. Wong Reviewed-by: Christoph Hellwig --- fs/xfs/libxfs/xfs_bmap.c | 170 +++++++++++++++++++++++++++++++++++++++ fs/xfs/libxfs/xfs_bmap.h | 1 + 2 files changed, 171 insertions(+) diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c index e88cdb6c75e9..8758000d82d2 100644 --- a/fs/xfs/libxfs/xfs_bmap.c +++ b/fs/xfs/libxfs/xfs_bmap.c @@ -4908,6 +4908,7 @@ xfs_bmap_del_extent( /* * Matches the whole extent. Delete the entry. */ + trace_xfs_bmap_pre_update(ip, *idx, state, _THIS_IP_); xfs_iext_remove(ip, *idx, 1, whichfork == XFS_ATTR_FORK ? BMAP_ATTRFORK : 0); --*idx; @@ -5124,6 +5125,175 @@ done: return error; } +/* Remove an extent from the CoW fork. Similar to xfs_bmap_del_extent. */ +int +xfs_bunmapi_cow( + struct xfs_inode *ip, + struct xfs_bmbt_irec *del) +{ + xfs_filblks_t da_new; + xfs_filblks_t da_old; + xfs_fsblock_t del_endblock = 0; + xfs_fileoff_t del_endoff; + int delay; + struct xfs_bmbt_rec_host *ep; + int error; + struct xfs_bmbt_irec got; + xfs_fileoff_t got_endoff; + struct xfs_ifork *ifp; + struct xfs_mount *mp; + xfs_filblks_t nblks; + struct xfs_bmbt_irec new; + /* REFERENCED */ + uint qfield; + xfs_filblks_t temp; + xfs_filblks_t temp2; + int state = BMAP_COWFORK; + int eof; + xfs_extnum_t eidx; + + mp = ip->i_mount; + XFS_STATS_INC(mp, xs_del_exlist); + + ep = xfs_bmap_search_extents(ip, del->br_startoff, XFS_COW_FORK, &eof, + &eidx, &got, &new); + + ifp = XFS_IFORK_PTR(ip, XFS_COW_FORK); ifp = ifp; + ASSERT((eidx >= 0) && (eidx < ifp->if_bytes / + (uint)sizeof(xfs_bmbt_rec_t))); + ASSERT(del->br_blockcount > 0); + ASSERT(got.br_startoff <= del->br_startoff); + del_endoff = del->br_startoff + del->br_blockcount; + got_endoff = got.br_startoff + got.br_blockcount; + ASSERT(got_endoff >= del_endoff); + delay = isnullstartblock(got.br_startblock); + ASSERT(isnullstartblock(del->br_startblock) == delay); + qfield = 0; + error = 0; + /* + * If deleting a real allocation, must free up the disk space. + */ + if (!delay) { + nblks = del->br_blockcount; + qfield = XFS_TRANS_DQ_BCOUNT; + /* + * Set up del_endblock and cur for later. + */ + del_endblock = del->br_startblock + del->br_blockcount; + da_old = da_new = 0; + } else { + da_old = startblockval(got.br_startblock); + da_new = 0; + nblks = 0; + } + qfield = qfield; + nblks = nblks; + + /* + * Set flag value to use in switch statement. + * Left-contig is 2, right-contig is 1. + */ + switch (((got.br_startoff == del->br_startoff) << 1) | + (got_endoff == del_endoff)) { + case 3: + /* + * Matches the whole extent. Delete the entry. + */ + xfs_iext_remove(ip, eidx, 1, BMAP_COWFORK); + --eidx; + break; + + case 2: + /* + * Deleting the first part of the extent. + */ + trace_xfs_bmap_pre_update(ip, eidx, state, _THIS_IP_); + xfs_bmbt_set_startoff(ep, del_endoff); + temp = got.br_blockcount - del->br_blockcount; + xfs_bmbt_set_blockcount(ep, temp); + if (delay) { + temp = XFS_FILBLKS_MIN(xfs_bmap_worst_indlen(ip, temp), + da_old); + xfs_bmbt_set_startblock(ep, nullstartblock((int)temp)); + trace_xfs_bmap_post_update(ip, eidx, state, _THIS_IP_); + da_new = temp; + break; + } + xfs_bmbt_set_startblock(ep, del_endblock); + trace_xfs_bmap_post_update(ip, eidx, state, _THIS_IP_); + break; + + case 1: + /* + * Deleting the last part of the extent. + */ + temp = got.br_blockcount - del->br_blockcount; + trace_xfs_bmap_pre_update(ip, eidx, state, _THIS_IP_); + xfs_bmbt_set_blockcount(ep, temp); + if (delay) { + temp = XFS_FILBLKS_MIN(xfs_bmap_worst_indlen(ip, temp), + da_old); + xfs_bmbt_set_startblock(ep, nullstartblock((int)temp)); + trace_xfs_bmap_post_update(ip, eidx, state, _THIS_IP_); + da_new = temp; + break; + } + trace_xfs_bmap_post_update(ip, eidx, state, _THIS_IP_); + break; + + case 0: + /* + * Deleting the middle of the extent. + */ + temp = del->br_startoff - got.br_startoff; + trace_xfs_bmap_pre_update(ip, eidx, state, _THIS_IP_); + xfs_bmbt_set_blockcount(ep, temp); + new.br_startoff = del_endoff; + temp2 = got_endoff - del_endoff; + new.br_blockcount = temp2; + new.br_state = got.br_state; + if (!delay) { + new.br_startblock = del_endblock; + } else { + temp = xfs_bmap_worst_indlen(ip, temp); + xfs_bmbt_set_startblock(ep, nullstartblock((int)temp)); + temp2 = xfs_bmap_worst_indlen(ip, temp2); + new.br_startblock = nullstartblock((int)temp2); + da_new = temp + temp2; + while (da_new > da_old) { + if (temp) { + temp--; + da_new--; + xfs_bmbt_set_startblock(ep, + nullstartblock((int)temp)); + } + if (da_new == da_old) + break; + if (temp2) { + temp2--; + da_new--; + new.br_startblock = + nullstartblock((int)temp2); + } + } + } + trace_xfs_bmap_post_update(ip, eidx, state, _THIS_IP_); + xfs_iext_insert(ip, eidx + 1, 1, &new, state); + ++eidx; + break; + } + + /* + * Account for change in delayed indirect blocks. + * Nothing to do for disk quota accounting here. + */ + ASSERT(da_old >= da_new); + if (da_old > da_new) + xfs_mod_fdblocks(mp, (int64_t)(da_old - da_new), false); + + return error; +} + /* * Unmap (remove) blocks from a file. * If nexts is nonzero then the number of extents to remove is limited to diff --git a/fs/xfs/libxfs/xfs_bmap.h b/fs/xfs/libxfs/xfs_bmap.h index c6fd52f40855..f97db7132564 100644 --- a/fs/xfs/libxfs/xfs_bmap.h +++ b/fs/xfs/libxfs/xfs_bmap.h @@ -221,6 +221,7 @@ int xfs_bunmapi(struct xfs_trans *tp, struct xfs_inode *ip, xfs_fileoff_t bno, xfs_filblks_t len, int flags, xfs_extnum_t nexts, xfs_fsblock_t *firstblock, struct xfs_defer_ops *dfops, int *done); +int xfs_bunmapi_cow(struct xfs_inode *ip, struct xfs_bmbt_irec *del); int xfs_check_nostate_extents(struct xfs_ifork *ifp, xfs_extnum_t idx, xfs_extnum_t num); uint xfs_default_attroffset(struct xfs_inode *ip); -- 2.20.1