forked from Minki/linux
5faaf4fa0a
There is no clear division of responsibility between those functions, so just merge them into one to keep the code simple. Also move xfs_file_wait_for_io to xfs_reflink.c together with its only caller. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
1772 lines
45 KiB
C
1772 lines
45 KiB
C
/*
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* Copyright (C) 2016 Oracle. All Rights Reserved.
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*
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* Author: Darrick J. Wong <darrick.wong@oracle.com>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it would be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
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*/
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#include "xfs.h"
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#include "xfs_fs.h"
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#include "xfs_shared.h"
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#include "xfs_format.h"
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#include "xfs_log_format.h"
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#include "xfs_trans_resv.h"
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#include "xfs_mount.h"
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#include "xfs_defer.h"
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#include "xfs_da_format.h"
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#include "xfs_da_btree.h"
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#include "xfs_inode.h"
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#include "xfs_trans.h"
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#include "xfs_inode_item.h"
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#include "xfs_bmap.h"
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#include "xfs_bmap_util.h"
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#include "xfs_error.h"
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#include "xfs_dir2.h"
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#include "xfs_dir2_priv.h"
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#include "xfs_ioctl.h"
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#include "xfs_trace.h"
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#include "xfs_log.h"
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#include "xfs_icache.h"
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#include "xfs_pnfs.h"
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#include "xfs_btree.h"
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#include "xfs_refcount_btree.h"
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#include "xfs_refcount.h"
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#include "xfs_bmap_btree.h"
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#include "xfs_trans_space.h"
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#include "xfs_bit.h"
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#include "xfs_alloc.h"
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#include "xfs_quota_defs.h"
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#include "xfs_quota.h"
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#include "xfs_btree.h"
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#include "xfs_bmap_btree.h"
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#include "xfs_reflink.h"
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#include "xfs_iomap.h"
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#include "xfs_rmap_btree.h"
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#include "xfs_sb.h"
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#include "xfs_ag_resv.h"
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/*
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* Copy on Write of Shared Blocks
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*
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* XFS must preserve "the usual" file semantics even when two files share
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* the same physical blocks. This means that a write to one file must not
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* alter the blocks in a different file; the way that we'll do that is
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* through the use of a copy-on-write mechanism. At a high level, that
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* means that when we want to write to a shared block, we allocate a new
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* block, write the data to the new block, and if that succeeds we map the
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* new block into the file.
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*
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* XFS provides a "delayed allocation" mechanism that defers the allocation
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* of disk blocks to dirty-but-not-yet-mapped file blocks as long as
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* possible. This reduces fragmentation by enabling the filesystem to ask
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* for bigger chunks less often, which is exactly what we want for CoW.
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*
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* The delalloc mechanism begins when the kernel wants to make a block
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* writable (write_begin or page_mkwrite). If the offset is not mapped, we
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* create a delalloc mapping, which is a regular in-core extent, but without
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* a real startblock. (For delalloc mappings, the startblock encodes both
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* a flag that this is a delalloc mapping, and a worst-case estimate of how
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* many blocks might be required to put the mapping into the BMBT.) delalloc
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* mappings are a reservation against the free space in the filesystem;
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* adjacent mappings can also be combined into fewer larger mappings.
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*
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* When dirty pages are being written out (typically in writepage), the
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* delalloc reservations are converted into real mappings by allocating
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* blocks and replacing the delalloc mapping with real ones. A delalloc
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* mapping can be replaced by several real ones if the free space is
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* fragmented.
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*
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* We want to adapt the delalloc mechanism for copy-on-write, since the
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* write paths are similar. The first two steps (creating the reservation
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* and allocating the blocks) are exactly the same as delalloc except that
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* the mappings must be stored in a separate CoW fork because we do not want
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* to disturb the mapping in the data fork until we're sure that the write
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* succeeded. IO completion in this case is the process of removing the old
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* mapping from the data fork and moving the new mapping from the CoW fork to
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* the data fork. This will be discussed shortly.
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*
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* For now, unaligned directio writes will be bounced back to the page cache.
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* Block-aligned directio writes will use the same mechanism as buffered
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* writes.
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*
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* CoW remapping must be done after the data block write completes,
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* because we don't want to destroy the old data fork map until we're sure
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* the new block has been written. Since the new mappings are kept in a
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* separate fork, we can simply iterate these mappings to find the ones
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* that cover the file blocks that we just CoW'd. For each extent, simply
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* unmap the corresponding range in the data fork, map the new range into
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* the data fork, and remove the extent from the CoW fork.
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*
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* Since the remapping operation can be applied to an arbitrary file
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* range, we record the need for the remap step as a flag in the ioend
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* instead of declaring a new IO type. This is required for direct io
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* because we only have ioend for the whole dio, and we have to be able to
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* remember the presence of unwritten blocks and CoW blocks with a single
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* ioend structure. Better yet, the more ground we can cover with one
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* ioend, the better.
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*/
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/*
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* Given an AG extent, find the lowest-numbered run of shared blocks
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* within that range and return the range in fbno/flen. If
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* find_end_of_shared is true, return the longest contiguous extent of
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* shared blocks. If there are no shared extents, fbno and flen will
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* be set to NULLAGBLOCK and 0, respectively.
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*/
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int
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xfs_reflink_find_shared(
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struct xfs_mount *mp,
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xfs_agnumber_t agno,
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xfs_agblock_t agbno,
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xfs_extlen_t aglen,
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xfs_agblock_t *fbno,
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xfs_extlen_t *flen,
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bool find_end_of_shared)
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{
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struct xfs_buf *agbp;
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struct xfs_btree_cur *cur;
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int error;
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error = xfs_alloc_read_agf(mp, NULL, agno, 0, &agbp);
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if (error)
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return error;
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cur = xfs_refcountbt_init_cursor(mp, NULL, agbp, agno, NULL);
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error = xfs_refcount_find_shared(cur, agbno, aglen, fbno, flen,
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find_end_of_shared);
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xfs_btree_del_cursor(cur, error ? XFS_BTREE_ERROR : XFS_BTREE_NOERROR);
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xfs_buf_relse(agbp);
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return error;
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}
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/*
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* Trim the mapping to the next block where there's a change in the
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* shared/unshared status. More specifically, this means that we
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* find the lowest-numbered extent of shared blocks that coincides with
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* the given block mapping. If the shared extent overlaps the start of
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* the mapping, trim the mapping to the end of the shared extent. If
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* the shared region intersects the mapping, trim the mapping to the
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* start of the shared extent. If there are no shared regions that
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* overlap, just return the original extent.
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*/
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int
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xfs_reflink_trim_around_shared(
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struct xfs_inode *ip,
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struct xfs_bmbt_irec *irec,
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bool *shared,
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bool *trimmed)
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{
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xfs_agnumber_t agno;
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xfs_agblock_t agbno;
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xfs_extlen_t aglen;
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xfs_agblock_t fbno;
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xfs_extlen_t flen;
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int error = 0;
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/* Holes, unwritten, and delalloc extents cannot be shared */
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if (!xfs_is_reflink_inode(ip) ||
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ISUNWRITTEN(irec) ||
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irec->br_startblock == HOLESTARTBLOCK ||
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irec->br_startblock == DELAYSTARTBLOCK) {
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*shared = false;
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return 0;
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}
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trace_xfs_reflink_trim_around_shared(ip, irec);
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agno = XFS_FSB_TO_AGNO(ip->i_mount, irec->br_startblock);
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agbno = XFS_FSB_TO_AGBNO(ip->i_mount, irec->br_startblock);
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aglen = irec->br_blockcount;
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error = xfs_reflink_find_shared(ip->i_mount, agno, agbno,
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aglen, &fbno, &flen, true);
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if (error)
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return error;
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*shared = *trimmed = false;
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if (fbno == NULLAGBLOCK) {
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/* No shared blocks at all. */
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return 0;
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} else if (fbno == agbno) {
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/*
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* The start of this extent is shared. Truncate the
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* mapping at the end of the shared region so that a
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* subsequent iteration starts at the start of the
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* unshared region.
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*/
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irec->br_blockcount = flen;
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*shared = true;
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if (flen != aglen)
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*trimmed = true;
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return 0;
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} else {
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/*
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* There's a shared extent midway through this extent.
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* Truncate the mapping at the start of the shared
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* extent so that a subsequent iteration starts at the
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* start of the shared region.
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*/
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irec->br_blockcount = fbno - agbno;
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*trimmed = true;
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return 0;
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}
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}
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/* Create a CoW reservation for a range of blocks within a file. */
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static int
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__xfs_reflink_reserve_cow(
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struct xfs_inode *ip,
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xfs_fileoff_t *offset_fsb,
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xfs_fileoff_t end_fsb,
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bool *skipped)
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{
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struct xfs_bmbt_irec got, prev, imap;
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xfs_fileoff_t orig_end_fsb;
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int nimaps, eof = 0, error = 0;
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bool shared = false, trimmed = false;
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xfs_extnum_t idx;
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xfs_extlen_t align;
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/* Already reserved? Skip the refcount btree access. */
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xfs_bmap_search_extents(ip, *offset_fsb, XFS_COW_FORK, &eof, &idx,
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&got, &prev);
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if (!eof && got.br_startoff <= *offset_fsb) {
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end_fsb = orig_end_fsb = got.br_startoff + got.br_blockcount;
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trace_xfs_reflink_cow_found(ip, &got);
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goto done;
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}
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/* Read extent from the source file. */
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nimaps = 1;
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error = xfs_bmapi_read(ip, *offset_fsb, end_fsb - *offset_fsb,
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&imap, &nimaps, 0);
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if (error)
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goto out_unlock;
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ASSERT(nimaps == 1);
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/* Trim the mapping to the nearest shared extent boundary. */
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error = xfs_reflink_trim_around_shared(ip, &imap, &shared, &trimmed);
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if (error)
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goto out_unlock;
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end_fsb = orig_end_fsb = imap.br_startoff + imap.br_blockcount;
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/* Not shared? Just report the (potentially capped) extent. */
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if (!shared) {
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*skipped = true;
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goto done;
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}
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/*
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* Fork all the shared blocks from our write offset until the end of
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* the extent.
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*/
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error = xfs_qm_dqattach_locked(ip, 0);
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if (error)
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goto out_unlock;
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align = xfs_eof_alignment(ip, xfs_get_cowextsz_hint(ip));
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if (align)
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end_fsb = roundup_64(end_fsb, align);
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retry:
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error = xfs_bmapi_reserve_delalloc(ip, XFS_COW_FORK, *offset_fsb,
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end_fsb - *offset_fsb, &got,
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&prev, &idx, eof);
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switch (error) {
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case 0:
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break;
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case -ENOSPC:
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case -EDQUOT:
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/* retry without any preallocation */
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trace_xfs_reflink_cow_enospc(ip, &imap);
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if (end_fsb != orig_end_fsb) {
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end_fsb = orig_end_fsb;
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goto retry;
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}
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/*FALLTHRU*/
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default:
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goto out_unlock;
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}
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if (end_fsb != orig_end_fsb)
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xfs_inode_set_cowblocks_tag(ip);
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trace_xfs_reflink_cow_alloc(ip, &got);
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done:
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*offset_fsb = end_fsb;
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out_unlock:
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return error;
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}
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|
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/* Create a CoW reservation for part of a file. */
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int
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xfs_reflink_reserve_cow_range(
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struct xfs_inode *ip,
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xfs_off_t offset,
|
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xfs_off_t count)
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{
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struct xfs_mount *mp = ip->i_mount;
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xfs_fileoff_t offset_fsb, end_fsb;
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bool skipped = false;
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int error = 0;
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trace_xfs_reflink_reserve_cow_range(ip, offset, count);
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offset_fsb = XFS_B_TO_FSBT(mp, offset);
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end_fsb = XFS_B_TO_FSB(mp, offset + count);
|
|
|
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xfs_ilock(ip, XFS_ILOCK_EXCL);
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while (offset_fsb < end_fsb) {
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error = __xfs_reflink_reserve_cow(ip, &offset_fsb, end_fsb,
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&skipped);
|
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if (error) {
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trace_xfs_reflink_reserve_cow_range_error(ip, error,
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_RET_IP_);
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break;
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}
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}
|
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xfs_iunlock(ip, XFS_ILOCK_EXCL);
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|
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return error;
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}
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|
|
|
/* Allocate all CoW reservations covering a range of blocks in a file. */
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|
static int
|
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__xfs_reflink_allocate_cow(
|
|
struct xfs_inode *ip,
|
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xfs_fileoff_t *offset_fsb,
|
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xfs_fileoff_t end_fsb)
|
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{
|
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struct xfs_mount *mp = ip->i_mount;
|
|
struct xfs_bmbt_irec imap;
|
|
struct xfs_defer_ops dfops;
|
|
struct xfs_trans *tp;
|
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xfs_fsblock_t first_block;
|
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xfs_fileoff_t next_fsb;
|
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int nimaps = 1, error;
|
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bool skipped = false;
|
|
|
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xfs_defer_init(&dfops, &first_block);
|
|
|
|
error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, 0, 0,
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XFS_TRANS_RESERVE, &tp);
|
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if (error)
|
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return error;
|
|
|
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xfs_ilock(ip, XFS_ILOCK_EXCL);
|
|
|
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next_fsb = *offset_fsb;
|
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error = __xfs_reflink_reserve_cow(ip, &next_fsb, end_fsb, &skipped);
|
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if (error)
|
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goto out_trans_cancel;
|
|
|
|
if (skipped) {
|
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*offset_fsb = next_fsb;
|
|
goto out_trans_cancel;
|
|
}
|
|
|
|
xfs_trans_ijoin(tp, ip, 0);
|
|
error = xfs_bmapi_write(tp, ip, *offset_fsb, next_fsb - *offset_fsb,
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|
XFS_BMAPI_COWFORK, &first_block,
|
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XFS_EXTENTADD_SPACE_RES(mp, XFS_DATA_FORK),
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&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);
|
|
|
|
out_unlock:
|
|
xfs_iunlock(ip, XFS_ILOCK_EXCL);
|
|
return error;
|
|
out_trans_cancel:
|
|
xfs_defer_cancel(&dfops);
|
|
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_);
|
|
break;
|
|
}
|
|
}
|
|
|
|
return error;
|
|
}
|
|
|
|
/*
|
|
* Find the CoW reservation (and whether or not it needs block allocation)
|
|
* for a given byte offset of a file.
|
|
*/
|
|
bool
|
|
xfs_reflink_find_cow_mapping(
|
|
struct xfs_inode *ip,
|
|
xfs_off_t offset,
|
|
struct xfs_bmbt_irec *imap,
|
|
bool *need_alloc)
|
|
{
|
|
struct xfs_bmbt_irec irec;
|
|
struct xfs_ifork *ifp;
|
|
struct xfs_bmbt_rec_host *gotp;
|
|
xfs_fileoff_t bno;
|
|
xfs_extnum_t idx;
|
|
|
|
ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL | XFS_ILOCK_SHARED));
|
|
ASSERT(xfs_is_reflink_inode(ip));
|
|
|
|
/* Find the extent in the CoW fork. */
|
|
ifp = XFS_IFORK_PTR(ip, XFS_COW_FORK);
|
|
bno = XFS_B_TO_FSBT(ip->i_mount, offset);
|
|
gotp = xfs_iext_bno_to_ext(ifp, bno, &idx);
|
|
if (!gotp)
|
|
return false;
|
|
|
|
xfs_bmbt_get_all(gotp, &irec);
|
|
if (bno >= irec.br_startoff + irec.br_blockcount ||
|
|
bno < irec.br_startoff)
|
|
return false;
|
|
|
|
trace_xfs_reflink_find_cow_mapping(ip, offset, 1, XFS_IO_OVERWRITE,
|
|
&irec);
|
|
|
|
/* If it's still delalloc, we must allocate later. */
|
|
*imap = irec;
|
|
*need_alloc = !!(isnullstartblock(irec.br_startblock));
|
|
|
|
return true;
|
|
}
|
|
|
|
/*
|
|
* Trim an extent to end at the next CoW reservation past offset_fsb.
|
|
*/
|
|
int
|
|
xfs_reflink_trim_irec_to_next_cow(
|
|
struct xfs_inode *ip,
|
|
xfs_fileoff_t offset_fsb,
|
|
struct xfs_bmbt_irec *imap)
|
|
{
|
|
struct xfs_bmbt_irec irec;
|
|
struct xfs_ifork *ifp;
|
|
struct xfs_bmbt_rec_host *gotp;
|
|
xfs_extnum_t idx;
|
|
|
|
if (!xfs_is_reflink_inode(ip))
|
|
return 0;
|
|
|
|
/* Find the extent in the CoW fork. */
|
|
ifp = XFS_IFORK_PTR(ip, XFS_COW_FORK);
|
|
gotp = xfs_iext_bno_to_ext(ifp, offset_fsb, &idx);
|
|
if (!gotp)
|
|
return 0;
|
|
xfs_bmbt_get_all(gotp, &irec);
|
|
|
|
/* This is the extent before; try sliding up one. */
|
|
if (irec.br_startoff < offset_fsb) {
|
|
idx++;
|
|
if (idx >= ifp->if_bytes / sizeof(xfs_bmbt_rec_t))
|
|
return 0;
|
|
gotp = xfs_iext_get_ext(ifp, idx);
|
|
xfs_bmbt_get_all(gotp, &irec);
|
|
}
|
|
|
|
if (irec.br_startoff >= imap->br_startoff + imap->br_blockcount)
|
|
return 0;
|
|
|
|
imap->br_blockcount = irec.br_startoff - imap->br_startoff;
|
|
trace_xfs_reflink_trim_irec(ip, imap);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Cancel all pending CoW reservations for some block range of an inode.
|
|
*/
|
|
int
|
|
xfs_reflink_cancel_cow_blocks(
|
|
struct xfs_inode *ip,
|
|
struct xfs_trans **tpp,
|
|
xfs_fileoff_t offset_fsb,
|
|
xfs_fileoff_t end_fsb)
|
|
{
|
|
struct xfs_bmbt_irec irec;
|
|
xfs_filblks_t count_fsb;
|
|
xfs_fsblock_t firstfsb;
|
|
struct xfs_defer_ops dfops;
|
|
int error = 0;
|
|
int nimaps;
|
|
|
|
if (!xfs_is_reflink_inode(ip))
|
|
return 0;
|
|
|
|
/* Go find the old extent in the CoW fork. */
|
|
while (offset_fsb < end_fsb) {
|
|
nimaps = 1;
|
|
count_fsb = (xfs_filblks_t)(end_fsb - offset_fsb);
|
|
error = xfs_bmapi_read(ip, offset_fsb, count_fsb, &irec,
|
|
&nimaps, XFS_BMAPI_COWFORK);
|
|
if (error)
|
|
break;
|
|
ASSERT(nimaps == 1);
|
|
|
|
trace_xfs_reflink_cancel_cow(ip, &irec);
|
|
|
|
if (irec.br_startblock == DELAYSTARTBLOCK) {
|
|
/* Free a delayed allocation. */
|
|
xfs_mod_fdblocks(ip->i_mount, irec.br_blockcount,
|
|
false);
|
|
ip->i_delayed_blks -= irec.br_blockcount;
|
|
|
|
/* Remove the mapping from the CoW fork. */
|
|
error = xfs_bunmapi_cow(ip, &irec);
|
|
if (error)
|
|
break;
|
|
} else if (irec.br_startblock == HOLESTARTBLOCK) {
|
|
/* empty */
|
|
} else {
|
|
xfs_trans_ijoin(*tpp, ip, 0);
|
|
xfs_defer_init(&dfops, &firstfsb);
|
|
|
|
/* Free the CoW orphan record. */
|
|
error = xfs_refcount_free_cow_extent(ip->i_mount,
|
|
&dfops, irec.br_startblock,
|
|
irec.br_blockcount);
|
|
if (error)
|
|
break;
|
|
|
|
xfs_bmap_add_free(ip->i_mount, &dfops,
|
|
irec.br_startblock, irec.br_blockcount,
|
|
NULL);
|
|
|
|
/* Update quota accounting */
|
|
xfs_trans_mod_dquot_byino(*tpp, ip, XFS_TRANS_DQ_BCOUNT,
|
|
-(long)irec.br_blockcount);
|
|
|
|
/* Roll the transaction */
|
|
error = xfs_defer_finish(tpp, &dfops, ip);
|
|
if (error) {
|
|
xfs_defer_cancel(&dfops);
|
|
break;
|
|
}
|
|
|
|
/* Remove the mapping from the CoW fork. */
|
|
error = xfs_bunmapi_cow(ip, &irec);
|
|
if (error)
|
|
break;
|
|
}
|
|
|
|
/* Roll on... */
|
|
offset_fsb = irec.br_startoff + irec.br_blockcount;
|
|
}
|
|
|
|
return error;
|
|
}
|
|
|
|
/*
|
|
* Cancel all pending CoW reservations for some byte range of an inode.
|
|
*/
|
|
int
|
|
xfs_reflink_cancel_cow_range(
|
|
struct xfs_inode *ip,
|
|
xfs_off_t offset,
|
|
xfs_off_t count)
|
|
{
|
|
struct xfs_trans *tp;
|
|
xfs_fileoff_t offset_fsb;
|
|
xfs_fileoff_t end_fsb;
|
|
int error;
|
|
|
|
trace_xfs_reflink_cancel_cow_range(ip, offset, count);
|
|
ASSERT(xfs_is_reflink_inode(ip));
|
|
|
|
offset_fsb = XFS_B_TO_FSBT(ip->i_mount, offset);
|
|
if (count == NULLFILEOFF)
|
|
end_fsb = NULLFILEOFF;
|
|
else
|
|
end_fsb = XFS_B_TO_FSB(ip->i_mount, offset + count);
|
|
|
|
/* Start a rolling transaction to remove the mappings */
|
|
error = xfs_trans_alloc(ip->i_mount, &M_RES(ip->i_mount)->tr_write,
|
|
0, 0, 0, &tp);
|
|
if (error)
|
|
goto out;
|
|
|
|
xfs_ilock(ip, XFS_ILOCK_EXCL);
|
|
xfs_trans_ijoin(tp, ip, 0);
|
|
|
|
/* Scrape out the old CoW reservations */
|
|
error = xfs_reflink_cancel_cow_blocks(ip, &tp, offset_fsb, end_fsb);
|
|
if (error)
|
|
goto out_cancel;
|
|
|
|
error = xfs_trans_commit(tp);
|
|
|
|
xfs_iunlock(ip, XFS_ILOCK_EXCL);
|
|
return error;
|
|
|
|
out_cancel:
|
|
xfs_trans_cancel(tp);
|
|
xfs_iunlock(ip, XFS_ILOCK_EXCL);
|
|
out:
|
|
trace_xfs_reflink_cancel_cow_range_error(ip, error, _RET_IP_);
|
|
return error;
|
|
}
|
|
|
|
/*
|
|
* Remap parts of a file's data fork after a successful CoW.
|
|
*/
|
|
int
|
|
xfs_reflink_end_cow(
|
|
struct xfs_inode *ip,
|
|
xfs_off_t offset,
|
|
xfs_off_t count)
|
|
{
|
|
struct xfs_bmbt_irec irec;
|
|
struct xfs_bmbt_irec uirec;
|
|
struct xfs_trans *tp;
|
|
xfs_fileoff_t offset_fsb;
|
|
xfs_fileoff_t end_fsb;
|
|
xfs_filblks_t count_fsb;
|
|
xfs_fsblock_t firstfsb;
|
|
struct xfs_defer_ops dfops;
|
|
int error;
|
|
unsigned int resblks;
|
|
xfs_filblks_t ilen;
|
|
xfs_filblks_t rlen;
|
|
int nimaps;
|
|
|
|
trace_xfs_reflink_end_cow(ip, offset, count);
|
|
|
|
offset_fsb = XFS_B_TO_FSBT(ip->i_mount, offset);
|
|
end_fsb = XFS_B_TO_FSB(ip->i_mount, offset + count);
|
|
count_fsb = (xfs_filblks_t)(end_fsb - offset_fsb);
|
|
|
|
/* Start a rolling transaction to switch the mappings */
|
|
resblks = XFS_EXTENTADD_SPACE_RES(ip->i_mount, XFS_DATA_FORK);
|
|
error = xfs_trans_alloc(ip->i_mount, &M_RES(ip->i_mount)->tr_write,
|
|
resblks, 0, 0, &tp);
|
|
if (error)
|
|
goto out;
|
|
|
|
xfs_ilock(ip, XFS_ILOCK_EXCL);
|
|
xfs_trans_ijoin(tp, ip, 0);
|
|
|
|
/* Go find the old extent in the CoW fork. */
|
|
while (offset_fsb < end_fsb) {
|
|
/* Read extent from the source file */
|
|
nimaps = 1;
|
|
count_fsb = (xfs_filblks_t)(end_fsb - offset_fsb);
|
|
error = xfs_bmapi_read(ip, offset_fsb, count_fsb, &irec,
|
|
&nimaps, XFS_BMAPI_COWFORK);
|
|
if (error)
|
|
goto out_cancel;
|
|
ASSERT(nimaps == 1);
|
|
|
|
ASSERT(irec.br_startblock != DELAYSTARTBLOCK);
|
|
trace_xfs_reflink_cow_remap(ip, &irec);
|
|
|
|
/*
|
|
* We can have a hole in the CoW fork if part of a directio
|
|
* write is CoW but part of it isn't.
|
|
*/
|
|
rlen = ilen = irec.br_blockcount;
|
|
if (irec.br_startblock == HOLESTARTBLOCK)
|
|
goto next_extent;
|
|
|
|
/* Unmap the old blocks in the data fork. */
|
|
while (rlen) {
|
|
xfs_defer_init(&dfops, &firstfsb);
|
|
error = __xfs_bunmapi(tp, ip, irec.br_startoff,
|
|
&rlen, 0, 1, &firstfsb, &dfops);
|
|
if (error)
|
|
goto out_defer;
|
|
|
|
/*
|
|
* Trim the extent to whatever got unmapped.
|
|
* Remember, bunmapi works backwards.
|
|
*/
|
|
uirec.br_startblock = irec.br_startblock + rlen;
|
|
uirec.br_startoff = irec.br_startoff + rlen;
|
|
uirec.br_blockcount = irec.br_blockcount - rlen;
|
|
irec.br_blockcount = rlen;
|
|
trace_xfs_reflink_cow_remap_piece(ip, &uirec);
|
|
|
|
/* Free the CoW orphan record. */
|
|
error = xfs_refcount_free_cow_extent(tp->t_mountp,
|
|
&dfops, uirec.br_startblock,
|
|
uirec.br_blockcount);
|
|
if (error)
|
|
goto out_defer;
|
|
|
|
/* Map the new blocks into the data fork. */
|
|
error = xfs_bmap_map_extent(tp->t_mountp, &dfops,
|
|
ip, &uirec);
|
|
if (error)
|
|
goto out_defer;
|
|
|
|
/* Remove the mapping from the CoW fork. */
|
|
error = xfs_bunmapi_cow(ip, &uirec);
|
|
if (error)
|
|
goto out_defer;
|
|
|
|
error = xfs_defer_finish(&tp, &dfops, ip);
|
|
if (error)
|
|
goto out_defer;
|
|
}
|
|
|
|
next_extent:
|
|
/* Roll on... */
|
|
offset_fsb = irec.br_startoff + ilen;
|
|
}
|
|
|
|
error = xfs_trans_commit(tp);
|
|
xfs_iunlock(ip, XFS_ILOCK_EXCL);
|
|
if (error)
|
|
goto out;
|
|
return 0;
|
|
|
|
out_defer:
|
|
xfs_defer_cancel(&dfops);
|
|
out_cancel:
|
|
xfs_trans_cancel(tp);
|
|
xfs_iunlock(ip, XFS_ILOCK_EXCL);
|
|
out:
|
|
trace_xfs_reflink_end_cow_error(ip, error, _RET_IP_);
|
|
return error;
|
|
}
|
|
|
|
/*
|
|
* Free leftover CoW reservations that didn't get cleaned out.
|
|
*/
|
|
int
|
|
xfs_reflink_recover_cow(
|
|
struct xfs_mount *mp)
|
|
{
|
|
xfs_agnumber_t agno;
|
|
int error = 0;
|
|
|
|
if (!xfs_sb_version_hasreflink(&mp->m_sb))
|
|
return 0;
|
|
|
|
for (agno = 0; agno < mp->m_sb.sb_agcount; agno++) {
|
|
error = xfs_refcount_recover_cow_leftovers(mp, agno);
|
|
if (error)
|
|
break;
|
|
}
|
|
|
|
return error;
|
|
}
|
|
|
|
/*
|
|
* Reflinking (Block) Ranges of Two Files Together
|
|
*
|
|
* First, ensure that the reflink flag is set on both inodes. The flag is an
|
|
* optimization to avoid unnecessary refcount btree lookups in the write path.
|
|
*
|
|
* Now we can iteratively remap the range of extents (and holes) in src to the
|
|
* corresponding ranges in dest. Let drange and srange denote the ranges of
|
|
* logical blocks in dest and src touched by the reflink operation.
|
|
*
|
|
* While the length of drange is greater than zero,
|
|
* - Read src's bmbt at the start of srange ("imap")
|
|
* - If imap doesn't exist, make imap appear to start at the end of srange
|
|
* with zero length.
|
|
* - If imap starts before srange, advance imap to start at srange.
|
|
* - If imap goes beyond srange, truncate imap to end at the end of srange.
|
|
* - Punch (imap start - srange start + imap len) blocks from dest at
|
|
* offset (drange start).
|
|
* - If imap points to a real range of pblks,
|
|
* > Increase the refcount of the imap's pblks
|
|
* > Map imap's pblks into dest at the offset
|
|
* (drange start + imap start - srange start)
|
|
* - Advance drange and srange by (imap start - srange start + imap len)
|
|
*
|
|
* Finally, if the reflink made dest longer, update both the in-core and
|
|
* on-disk file sizes.
|
|
*
|
|
* ASCII Art Demonstration:
|
|
*
|
|
* Let's say we want to reflink this source file:
|
|
*
|
|
* ----SSSSSSS-SSSSS----SSSSSS (src file)
|
|
* <-------------------->
|
|
*
|
|
* into this destination file:
|
|
*
|
|
* --DDDDDDDDDDDDDDDDDDD--DDD (dest file)
|
|
* <-------------------->
|
|
* '-' means a hole, and 'S' and 'D' are written blocks in the src and dest.
|
|
* Observe that the range has different logical offsets in either file.
|
|
*
|
|
* Consider that the first extent in the source file doesn't line up with our
|
|
* reflink range. Unmapping and remapping are separate operations, so we can
|
|
* unmap more blocks from the destination file than we remap.
|
|
*
|
|
* ----SSSSSSS-SSSSS----SSSSSS
|
|
* <------->
|
|
* --DDDDD---------DDDDD--DDD
|
|
* <------->
|
|
*
|
|
* Now remap the source extent into the destination file:
|
|
*
|
|
* ----SSSSSSS-SSSSS----SSSSSS
|
|
* <------->
|
|
* --DDDDD--SSSSSSSDDDDD--DDD
|
|
* <------->
|
|
*
|
|
* Do likewise with the second hole and extent in our range. Holes in the
|
|
* unmap range don't affect our operation.
|
|
*
|
|
* ----SSSSSSS-SSSSS----SSSSSS
|
|
* <---->
|
|
* --DDDDD--SSSSSSS-SSSSS-DDD
|
|
* <---->
|
|
*
|
|
* Finally, unmap and remap part of the third extent. This will increase the
|
|
* size of the destination file.
|
|
*
|
|
* ----SSSSSSS-SSSSS----SSSSSS
|
|
* <----->
|
|
* --DDDDD--SSSSSSS-SSSSS----SSS
|
|
* <----->
|
|
*
|
|
* Once we update the destination file's i_size, we're done.
|
|
*/
|
|
|
|
/*
|
|
* Ensure the reflink bit is set in both inodes.
|
|
*/
|
|
STATIC int
|
|
xfs_reflink_set_inode_flag(
|
|
struct xfs_inode *src,
|
|
struct xfs_inode *dest)
|
|
{
|
|
struct xfs_mount *mp = src->i_mount;
|
|
int error;
|
|
struct xfs_trans *tp;
|
|
|
|
if (xfs_is_reflink_inode(src) && xfs_is_reflink_inode(dest))
|
|
return 0;
|
|
|
|
error = xfs_trans_alloc(mp, &M_RES(mp)->tr_ichange, 0, 0, 0, &tp);
|
|
if (error)
|
|
goto out_error;
|
|
|
|
/* Lock both files against IO */
|
|
if (src->i_ino == dest->i_ino)
|
|
xfs_ilock(src, XFS_ILOCK_EXCL);
|
|
else
|
|
xfs_lock_two_inodes(src, dest, XFS_ILOCK_EXCL);
|
|
|
|
if (!xfs_is_reflink_inode(src)) {
|
|
trace_xfs_reflink_set_inode_flag(src);
|
|
xfs_trans_ijoin(tp, src, XFS_ILOCK_EXCL);
|
|
src->i_d.di_flags2 |= XFS_DIFLAG2_REFLINK;
|
|
xfs_trans_log_inode(tp, src, XFS_ILOG_CORE);
|
|
xfs_ifork_init_cow(src);
|
|
} else
|
|
xfs_iunlock(src, XFS_ILOCK_EXCL);
|
|
|
|
if (src->i_ino == dest->i_ino)
|
|
goto commit_flags;
|
|
|
|
if (!xfs_is_reflink_inode(dest)) {
|
|
trace_xfs_reflink_set_inode_flag(dest);
|
|
xfs_trans_ijoin(tp, dest, XFS_ILOCK_EXCL);
|
|
dest->i_d.di_flags2 |= XFS_DIFLAG2_REFLINK;
|
|
xfs_trans_log_inode(tp, dest, XFS_ILOG_CORE);
|
|
xfs_ifork_init_cow(dest);
|
|
} else
|
|
xfs_iunlock(dest, XFS_ILOCK_EXCL);
|
|
|
|
commit_flags:
|
|
error = xfs_trans_commit(tp);
|
|
if (error)
|
|
goto out_error;
|
|
return error;
|
|
|
|
out_error:
|
|
trace_xfs_reflink_set_inode_flag_error(dest, error, _RET_IP_);
|
|
return error;
|
|
}
|
|
|
|
/*
|
|
* Update destination inode size & cowextsize hint, if necessary.
|
|
*/
|
|
STATIC int
|
|
xfs_reflink_update_dest(
|
|
struct xfs_inode *dest,
|
|
xfs_off_t newlen,
|
|
xfs_extlen_t cowextsize)
|
|
{
|
|
struct xfs_mount *mp = dest->i_mount;
|
|
struct xfs_trans *tp;
|
|
int error;
|
|
|
|
if (newlen <= i_size_read(VFS_I(dest)) && cowextsize == 0)
|
|
return 0;
|
|
|
|
error = xfs_trans_alloc(mp, &M_RES(mp)->tr_ichange, 0, 0, 0, &tp);
|
|
if (error)
|
|
goto out_error;
|
|
|
|
xfs_ilock(dest, XFS_ILOCK_EXCL);
|
|
xfs_trans_ijoin(tp, dest, XFS_ILOCK_EXCL);
|
|
|
|
if (newlen > i_size_read(VFS_I(dest))) {
|
|
trace_xfs_reflink_update_inode_size(dest, newlen);
|
|
i_size_write(VFS_I(dest), newlen);
|
|
dest->i_d.di_size = newlen;
|
|
}
|
|
|
|
if (cowextsize) {
|
|
dest->i_d.di_cowextsize = cowextsize;
|
|
dest->i_d.di_flags2 |= XFS_DIFLAG2_COWEXTSIZE;
|
|
}
|
|
|
|
xfs_trans_log_inode(tp, dest, XFS_ILOG_CORE);
|
|
|
|
error = xfs_trans_commit(tp);
|
|
if (error)
|
|
goto out_error;
|
|
return error;
|
|
|
|
out_error:
|
|
trace_xfs_reflink_update_inode_size_error(dest, error, _RET_IP_);
|
|
return error;
|
|
}
|
|
|
|
/*
|
|
* Do we have enough reserve in this AG to handle a reflink? The refcount
|
|
* btree already reserved all the space it needs, but the rmap btree can grow
|
|
* infinitely, so we won't allow more reflinks when the AG is down to the
|
|
* btree reserves.
|
|
*/
|
|
static int
|
|
xfs_reflink_ag_has_free_space(
|
|
struct xfs_mount *mp,
|
|
xfs_agnumber_t agno)
|
|
{
|
|
struct xfs_perag *pag;
|
|
int error = 0;
|
|
|
|
if (!xfs_sb_version_hasrmapbt(&mp->m_sb))
|
|
return 0;
|
|
|
|
pag = xfs_perag_get(mp, agno);
|
|
if (xfs_ag_resv_critical(pag, XFS_AG_RESV_AGFL) ||
|
|
xfs_ag_resv_critical(pag, XFS_AG_RESV_METADATA))
|
|
error = -ENOSPC;
|
|
xfs_perag_put(pag);
|
|
return error;
|
|
}
|
|
|
|
/*
|
|
* Unmap a range of blocks from a file, then map other blocks into the hole.
|
|
* The range to unmap is (destoff : destoff + srcioff + irec->br_blockcount).
|
|
* The extent irec is mapped into dest at irec->br_startoff.
|
|
*/
|
|
STATIC int
|
|
xfs_reflink_remap_extent(
|
|
struct xfs_inode *ip,
|
|
struct xfs_bmbt_irec *irec,
|
|
xfs_fileoff_t destoff,
|
|
xfs_off_t new_isize)
|
|
{
|
|
struct xfs_mount *mp = ip->i_mount;
|
|
struct xfs_trans *tp;
|
|
xfs_fsblock_t firstfsb;
|
|
unsigned int resblks;
|
|
struct xfs_defer_ops dfops;
|
|
struct xfs_bmbt_irec uirec;
|
|
bool real_extent;
|
|
xfs_filblks_t rlen;
|
|
xfs_filblks_t unmap_len;
|
|
xfs_off_t newlen;
|
|
int error;
|
|
|
|
unmap_len = irec->br_startoff + irec->br_blockcount - destoff;
|
|
trace_xfs_reflink_punch_range(ip, destoff, unmap_len);
|
|
|
|
/* Only remap normal extents. */
|
|
real_extent = (irec->br_startblock != HOLESTARTBLOCK &&
|
|
irec->br_startblock != DELAYSTARTBLOCK &&
|
|
!ISUNWRITTEN(irec));
|
|
|
|
/* No reflinking if we're low on space */
|
|
if (real_extent) {
|
|
error = xfs_reflink_ag_has_free_space(mp,
|
|
XFS_FSB_TO_AGNO(mp, irec->br_startblock));
|
|
if (error)
|
|
goto out;
|
|
}
|
|
|
|
/* Start a rolling transaction to switch the mappings */
|
|
resblks = XFS_EXTENTADD_SPACE_RES(ip->i_mount, XFS_DATA_FORK);
|
|
error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, resblks, 0, 0, &tp);
|
|
if (error)
|
|
goto out;
|
|
|
|
xfs_ilock(ip, XFS_ILOCK_EXCL);
|
|
xfs_trans_ijoin(tp, ip, 0);
|
|
|
|
/* If we're not just clearing space, then do we have enough quota? */
|
|
if (real_extent) {
|
|
error = xfs_trans_reserve_quota_nblks(tp, ip,
|
|
irec->br_blockcount, 0, XFS_QMOPT_RES_REGBLKS);
|
|
if (error)
|
|
goto out_cancel;
|
|
}
|
|
|
|
trace_xfs_reflink_remap(ip, irec->br_startoff,
|
|
irec->br_blockcount, irec->br_startblock);
|
|
|
|
/* Unmap the old blocks in the data fork. */
|
|
rlen = unmap_len;
|
|
while (rlen) {
|
|
xfs_defer_init(&dfops, &firstfsb);
|
|
error = __xfs_bunmapi(tp, ip, destoff, &rlen, 0, 1,
|
|
&firstfsb, &dfops);
|
|
if (error)
|
|
goto out_defer;
|
|
|
|
/*
|
|
* Trim the extent to whatever got unmapped.
|
|
* Remember, bunmapi works backwards.
|
|
*/
|
|
uirec.br_startblock = irec->br_startblock + rlen;
|
|
uirec.br_startoff = irec->br_startoff + rlen;
|
|
uirec.br_blockcount = unmap_len - rlen;
|
|
unmap_len = rlen;
|
|
|
|
/* If this isn't a real mapping, we're done. */
|
|
if (!real_extent || uirec.br_blockcount == 0)
|
|
goto next_extent;
|
|
|
|
trace_xfs_reflink_remap(ip, uirec.br_startoff,
|
|
uirec.br_blockcount, uirec.br_startblock);
|
|
|
|
/* Update the refcount tree */
|
|
error = xfs_refcount_increase_extent(mp, &dfops, &uirec);
|
|
if (error)
|
|
goto out_defer;
|
|
|
|
/* Map the new blocks into the data fork. */
|
|
error = xfs_bmap_map_extent(mp, &dfops, ip, &uirec);
|
|
if (error)
|
|
goto out_defer;
|
|
|
|
/* Update quota accounting. */
|
|
xfs_trans_mod_dquot_byino(tp, ip, XFS_TRANS_DQ_BCOUNT,
|
|
uirec.br_blockcount);
|
|
|
|
/* Update dest isize if needed. */
|
|
newlen = XFS_FSB_TO_B(mp,
|
|
uirec.br_startoff + uirec.br_blockcount);
|
|
newlen = min_t(xfs_off_t, newlen, new_isize);
|
|
if (newlen > i_size_read(VFS_I(ip))) {
|
|
trace_xfs_reflink_update_inode_size(ip, newlen);
|
|
i_size_write(VFS_I(ip), newlen);
|
|
ip->i_d.di_size = newlen;
|
|
xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
|
|
}
|
|
|
|
next_extent:
|
|
/* Process all the deferred stuff. */
|
|
error = xfs_defer_finish(&tp, &dfops, ip);
|
|
if (error)
|
|
goto out_defer;
|
|
}
|
|
|
|
error = xfs_trans_commit(tp);
|
|
xfs_iunlock(ip, XFS_ILOCK_EXCL);
|
|
if (error)
|
|
goto out;
|
|
return 0;
|
|
|
|
out_defer:
|
|
xfs_defer_cancel(&dfops);
|
|
out_cancel:
|
|
xfs_trans_cancel(tp);
|
|
xfs_iunlock(ip, XFS_ILOCK_EXCL);
|
|
out:
|
|
trace_xfs_reflink_remap_extent_error(ip, error, _RET_IP_);
|
|
return error;
|
|
}
|
|
|
|
/*
|
|
* Iteratively remap one file's extents (and holes) to another's.
|
|
*/
|
|
STATIC int
|
|
xfs_reflink_remap_blocks(
|
|
struct xfs_inode *src,
|
|
xfs_fileoff_t srcoff,
|
|
struct xfs_inode *dest,
|
|
xfs_fileoff_t destoff,
|
|
xfs_filblks_t len,
|
|
xfs_off_t new_isize)
|
|
{
|
|
struct xfs_bmbt_irec imap;
|
|
int nimaps;
|
|
int error = 0;
|
|
xfs_filblks_t range_len;
|
|
|
|
/* drange = (destoff, destoff + len); srange = (srcoff, srcoff + len) */
|
|
while (len) {
|
|
trace_xfs_reflink_remap_blocks_loop(src, srcoff, len,
|
|
dest, destoff);
|
|
/* Read extent from the source file */
|
|
nimaps = 1;
|
|
xfs_ilock(src, XFS_ILOCK_EXCL);
|
|
error = xfs_bmapi_read(src, srcoff, len, &imap, &nimaps, 0);
|
|
xfs_iunlock(src, XFS_ILOCK_EXCL);
|
|
if (error)
|
|
goto err;
|
|
ASSERT(nimaps == 1);
|
|
|
|
trace_xfs_reflink_remap_imap(src, srcoff, len, XFS_IO_OVERWRITE,
|
|
&imap);
|
|
|
|
/* Translate imap into the destination file. */
|
|
range_len = imap.br_startoff + imap.br_blockcount - srcoff;
|
|
imap.br_startoff += destoff - srcoff;
|
|
|
|
/* Clear dest from destoff to the end of imap and map it in. */
|
|
error = xfs_reflink_remap_extent(dest, &imap, destoff,
|
|
new_isize);
|
|
if (error)
|
|
goto err;
|
|
|
|
if (fatal_signal_pending(current)) {
|
|
error = -EINTR;
|
|
goto err;
|
|
}
|
|
|
|
/* Advance drange/srange */
|
|
srcoff += range_len;
|
|
destoff += range_len;
|
|
len -= range_len;
|
|
}
|
|
|
|
return 0;
|
|
|
|
err:
|
|
trace_xfs_reflink_remap_blocks_error(dest, error, _RET_IP_);
|
|
return error;
|
|
}
|
|
|
|
/*
|
|
* Read a page's worth of file data into the page cache. Return the page
|
|
* locked.
|
|
*/
|
|
static struct page *
|
|
xfs_get_page(
|
|
struct inode *inode,
|
|
xfs_off_t offset)
|
|
{
|
|
struct address_space *mapping;
|
|
struct page *page;
|
|
pgoff_t n;
|
|
|
|
n = offset >> PAGE_SHIFT;
|
|
mapping = inode->i_mapping;
|
|
page = read_mapping_page(mapping, n, NULL);
|
|
if (IS_ERR(page))
|
|
return page;
|
|
if (!PageUptodate(page)) {
|
|
put_page(page);
|
|
return ERR_PTR(-EIO);
|
|
}
|
|
lock_page(page);
|
|
return page;
|
|
}
|
|
|
|
/*
|
|
* Compare extents of two files to see if they are the same.
|
|
*/
|
|
static int
|
|
xfs_compare_extents(
|
|
struct inode *src,
|
|
xfs_off_t srcoff,
|
|
struct inode *dest,
|
|
xfs_off_t destoff,
|
|
xfs_off_t len,
|
|
bool *is_same)
|
|
{
|
|
xfs_off_t src_poff;
|
|
xfs_off_t dest_poff;
|
|
void *src_addr;
|
|
void *dest_addr;
|
|
struct page *src_page;
|
|
struct page *dest_page;
|
|
xfs_off_t cmp_len;
|
|
bool same;
|
|
int error;
|
|
|
|
error = -EINVAL;
|
|
same = true;
|
|
while (len) {
|
|
src_poff = srcoff & (PAGE_SIZE - 1);
|
|
dest_poff = destoff & (PAGE_SIZE - 1);
|
|
cmp_len = min(PAGE_SIZE - src_poff,
|
|
PAGE_SIZE - dest_poff);
|
|
cmp_len = min(cmp_len, len);
|
|
ASSERT(cmp_len > 0);
|
|
|
|
trace_xfs_reflink_compare_extents(XFS_I(src), srcoff, cmp_len,
|
|
XFS_I(dest), destoff);
|
|
|
|
src_page = xfs_get_page(src, srcoff);
|
|
if (IS_ERR(src_page)) {
|
|
error = PTR_ERR(src_page);
|
|
goto out_error;
|
|
}
|
|
dest_page = xfs_get_page(dest, destoff);
|
|
if (IS_ERR(dest_page)) {
|
|
error = PTR_ERR(dest_page);
|
|
unlock_page(src_page);
|
|
put_page(src_page);
|
|
goto out_error;
|
|
}
|
|
src_addr = kmap_atomic(src_page);
|
|
dest_addr = kmap_atomic(dest_page);
|
|
|
|
flush_dcache_page(src_page);
|
|
flush_dcache_page(dest_page);
|
|
|
|
if (memcmp(src_addr + src_poff, dest_addr + dest_poff, cmp_len))
|
|
same = false;
|
|
|
|
kunmap_atomic(dest_addr);
|
|
kunmap_atomic(src_addr);
|
|
unlock_page(dest_page);
|
|
unlock_page(src_page);
|
|
put_page(dest_page);
|
|
put_page(src_page);
|
|
|
|
if (!same)
|
|
break;
|
|
|
|
srcoff += cmp_len;
|
|
destoff += cmp_len;
|
|
len -= cmp_len;
|
|
}
|
|
|
|
*is_same = same;
|
|
return 0;
|
|
|
|
out_error:
|
|
trace_xfs_reflink_compare_extents_error(XFS_I(dest), error, _RET_IP_);
|
|
return error;
|
|
}
|
|
|
|
/*
|
|
* Link a range of blocks from one file to another.
|
|
*/
|
|
int
|
|
xfs_reflink_remap_range(
|
|
struct file *file_in,
|
|
loff_t pos_in,
|
|
struct file *file_out,
|
|
loff_t pos_out,
|
|
u64 len,
|
|
bool is_dedupe)
|
|
{
|
|
struct inode *inode_in = file_inode(file_in);
|
|
struct xfs_inode *src = XFS_I(inode_in);
|
|
struct inode *inode_out = file_inode(file_out);
|
|
struct xfs_inode *dest = XFS_I(inode_out);
|
|
struct xfs_mount *mp = src->i_mount;
|
|
loff_t bs = inode_out->i_sb->s_blocksize;
|
|
bool same_inode = (inode_in == inode_out);
|
|
xfs_fileoff_t sfsbno, dfsbno;
|
|
xfs_filblks_t fsblen;
|
|
xfs_extlen_t cowextsize;
|
|
loff_t isize;
|
|
ssize_t ret;
|
|
loff_t blen;
|
|
|
|
if (!xfs_sb_version_hasreflink(&mp->m_sb))
|
|
return -EOPNOTSUPP;
|
|
|
|
if (XFS_FORCED_SHUTDOWN(mp))
|
|
return -EIO;
|
|
|
|
/* Lock both files against IO */
|
|
if (same_inode) {
|
|
xfs_ilock(src, XFS_IOLOCK_EXCL);
|
|
xfs_ilock(src, XFS_MMAPLOCK_EXCL);
|
|
} else {
|
|
xfs_lock_two_inodes(src, dest, XFS_IOLOCK_EXCL);
|
|
xfs_lock_two_inodes(src, dest, XFS_MMAPLOCK_EXCL);
|
|
}
|
|
|
|
/* Don't touch certain kinds of inodes */
|
|
ret = -EPERM;
|
|
if (IS_IMMUTABLE(inode_out))
|
|
goto out_unlock;
|
|
|
|
ret = -ETXTBSY;
|
|
if (IS_SWAPFILE(inode_in) || IS_SWAPFILE(inode_out))
|
|
goto out_unlock;
|
|
|
|
|
|
/* Don't reflink dirs, pipes, sockets... */
|
|
ret = -EISDIR;
|
|
if (S_ISDIR(inode_in->i_mode) || S_ISDIR(inode_out->i_mode))
|
|
goto out_unlock;
|
|
ret = -EINVAL;
|
|
if (S_ISFIFO(inode_in->i_mode) || S_ISFIFO(inode_out->i_mode))
|
|
goto out_unlock;
|
|
if (!S_ISREG(inode_in->i_mode) || !S_ISREG(inode_out->i_mode))
|
|
goto out_unlock;
|
|
|
|
/* Don't reflink realtime inodes */
|
|
if (XFS_IS_REALTIME_INODE(src) || XFS_IS_REALTIME_INODE(dest))
|
|
goto out_unlock;
|
|
|
|
/* Don't share DAX file data for now. */
|
|
if (IS_DAX(inode_in) || IS_DAX(inode_out))
|
|
goto out_unlock;
|
|
|
|
/* Are we going all the way to the end? */
|
|
isize = i_size_read(inode_in);
|
|
if (isize == 0) {
|
|
ret = 0;
|
|
goto out_unlock;
|
|
}
|
|
|
|
if (len == 0)
|
|
len = isize - pos_in;
|
|
|
|
/* Ensure offsets don't wrap and the input is inside i_size */
|
|
if (pos_in + len < pos_in || pos_out + len < pos_out ||
|
|
pos_in + len > isize)
|
|
goto out_unlock;
|
|
|
|
/* Don't allow dedupe past EOF in the dest file */
|
|
if (is_dedupe) {
|
|
loff_t disize;
|
|
|
|
disize = i_size_read(inode_out);
|
|
if (pos_out >= disize || pos_out + len > disize)
|
|
goto out_unlock;
|
|
}
|
|
|
|
/* If we're linking to EOF, continue to the block boundary. */
|
|
if (pos_in + len == isize)
|
|
blen = ALIGN(isize, bs) - pos_in;
|
|
else
|
|
blen = len;
|
|
|
|
/* Only reflink if we're aligned to block boundaries */
|
|
if (!IS_ALIGNED(pos_in, bs) || !IS_ALIGNED(pos_in + blen, bs) ||
|
|
!IS_ALIGNED(pos_out, bs) || !IS_ALIGNED(pos_out + blen, bs))
|
|
goto out_unlock;
|
|
|
|
/* Don't allow overlapped reflink within the same file */
|
|
if (same_inode) {
|
|
if (pos_out + blen > pos_in && pos_out < pos_in + blen)
|
|
goto out_unlock;
|
|
}
|
|
|
|
/* Wait for the completion of any pending IOs on both files */
|
|
inode_dio_wait(inode_in);
|
|
if (!same_inode)
|
|
inode_dio_wait(inode_out);
|
|
|
|
ret = filemap_write_and_wait_range(inode_in->i_mapping,
|
|
pos_in, pos_in + len - 1);
|
|
if (ret)
|
|
goto out_unlock;
|
|
|
|
ret = filemap_write_and_wait_range(inode_out->i_mapping,
|
|
pos_out, pos_out + len - 1);
|
|
if (ret)
|
|
goto out_unlock;
|
|
|
|
trace_xfs_reflink_remap_range(src, pos_in, len, dest, pos_out);
|
|
|
|
/*
|
|
* Check that the extents are the same.
|
|
*/
|
|
if (is_dedupe) {
|
|
bool is_same = false;
|
|
|
|
ret = xfs_compare_extents(inode_in, pos_in, inode_out, pos_out,
|
|
len, &is_same);
|
|
if (ret)
|
|
goto out_unlock;
|
|
if (!is_same) {
|
|
ret = -EBADE;
|
|
goto out_unlock;
|
|
}
|
|
}
|
|
|
|
ret = xfs_reflink_set_inode_flag(src, dest);
|
|
if (ret)
|
|
goto out_unlock;
|
|
|
|
/*
|
|
* Invalidate the page cache so that we can clear any CoW mappings
|
|
* in the destination file.
|
|
*/
|
|
truncate_inode_pages_range(&inode_out->i_data, pos_out,
|
|
PAGE_ALIGN(pos_out + len) - 1);
|
|
|
|
dfsbno = XFS_B_TO_FSBT(mp, pos_out);
|
|
sfsbno = XFS_B_TO_FSBT(mp, pos_in);
|
|
fsblen = XFS_B_TO_FSB(mp, len);
|
|
ret = xfs_reflink_remap_blocks(src, sfsbno, dest, dfsbno, fsblen,
|
|
pos_out + len);
|
|
if (ret)
|
|
goto out_unlock;
|
|
|
|
/*
|
|
* Carry the cowextsize hint from src to dest if we're sharing the
|
|
* entire source file to the entire destination file, the source file
|
|
* has a cowextsize hint, and the destination file does not.
|
|
*/
|
|
cowextsize = 0;
|
|
if (pos_in == 0 && len == i_size_read(inode_in) &&
|
|
(src->i_d.di_flags2 & XFS_DIFLAG2_COWEXTSIZE) &&
|
|
pos_out == 0 && len >= i_size_read(inode_out) &&
|
|
!(dest->i_d.di_flags2 & XFS_DIFLAG2_COWEXTSIZE))
|
|
cowextsize = src->i_d.di_cowextsize;
|
|
|
|
ret = xfs_reflink_update_dest(dest, pos_out + len, cowextsize);
|
|
|
|
out_unlock:
|
|
xfs_iunlock(src, XFS_MMAPLOCK_EXCL);
|
|
xfs_iunlock(src, XFS_IOLOCK_EXCL);
|
|
if (src->i_ino != dest->i_ino) {
|
|
xfs_iunlock(dest, XFS_MMAPLOCK_EXCL);
|
|
xfs_iunlock(dest, XFS_IOLOCK_EXCL);
|
|
}
|
|
if (ret)
|
|
trace_xfs_reflink_remap_range_error(dest, ret, _RET_IP_);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* The user wants to preemptively CoW all shared blocks in this file,
|
|
* which enables us to turn off the reflink flag. Iterate all
|
|
* extents which are not prealloc/delalloc to see which ranges are
|
|
* mentioned in the refcount tree, then read those blocks into the
|
|
* pagecache, dirty them, fsync them back out, and then we can update
|
|
* the inode flag. What happens if we run out of memory? :)
|
|
*/
|
|
STATIC int
|
|
xfs_reflink_dirty_extents(
|
|
struct xfs_inode *ip,
|
|
xfs_fileoff_t fbno,
|
|
xfs_filblks_t end,
|
|
xfs_off_t isize)
|
|
{
|
|
struct xfs_mount *mp = ip->i_mount;
|
|
xfs_agnumber_t agno;
|
|
xfs_agblock_t agbno;
|
|
xfs_extlen_t aglen;
|
|
xfs_agblock_t rbno;
|
|
xfs_extlen_t rlen;
|
|
xfs_off_t fpos;
|
|
xfs_off_t flen;
|
|
struct xfs_bmbt_irec map[2];
|
|
int nmaps;
|
|
int error = 0;
|
|
|
|
while (end - fbno > 0) {
|
|
nmaps = 1;
|
|
/*
|
|
* Look for extents in the file. Skip holes, delalloc, or
|
|
* unwritten extents; they can't be reflinked.
|
|
*/
|
|
error = xfs_bmapi_read(ip, fbno, end - fbno, map, &nmaps, 0);
|
|
if (error)
|
|
goto out;
|
|
if (nmaps == 0)
|
|
break;
|
|
if (map[0].br_startblock == HOLESTARTBLOCK ||
|
|
map[0].br_startblock == DELAYSTARTBLOCK ||
|
|
ISUNWRITTEN(&map[0]))
|
|
goto next;
|
|
|
|
map[1] = map[0];
|
|
while (map[1].br_blockcount) {
|
|
agno = XFS_FSB_TO_AGNO(mp, map[1].br_startblock);
|
|
agbno = XFS_FSB_TO_AGBNO(mp, map[1].br_startblock);
|
|
aglen = map[1].br_blockcount;
|
|
|
|
error = xfs_reflink_find_shared(mp, agno, agbno, aglen,
|
|
&rbno, &rlen, true);
|
|
if (error)
|
|
goto out;
|
|
if (rbno == NULLAGBLOCK)
|
|
break;
|
|
|
|
/* Dirty the pages */
|
|
xfs_iunlock(ip, XFS_ILOCK_EXCL);
|
|
fpos = XFS_FSB_TO_B(mp, map[1].br_startoff +
|
|
(rbno - agbno));
|
|
flen = XFS_FSB_TO_B(mp, rlen);
|
|
if (fpos + flen > isize)
|
|
flen = isize - fpos;
|
|
error = iomap_file_dirty(VFS_I(ip), fpos, flen,
|
|
&xfs_iomap_ops);
|
|
xfs_ilock(ip, XFS_ILOCK_EXCL);
|
|
if (error)
|
|
goto out;
|
|
|
|
map[1].br_blockcount -= (rbno - agbno + rlen);
|
|
map[1].br_startoff += (rbno - agbno + rlen);
|
|
map[1].br_startblock += (rbno - agbno + rlen);
|
|
}
|
|
|
|
next:
|
|
fbno = map[0].br_startoff + map[0].br_blockcount;
|
|
}
|
|
out:
|
|
return error;
|
|
}
|
|
|
|
/* Clear the inode reflink flag if there are no shared extents. */
|
|
int
|
|
xfs_reflink_clear_inode_flag(
|
|
struct xfs_inode *ip,
|
|
struct xfs_trans **tpp)
|
|
{
|
|
struct xfs_mount *mp = ip->i_mount;
|
|
xfs_fileoff_t fbno;
|
|
xfs_filblks_t end;
|
|
xfs_agnumber_t agno;
|
|
xfs_agblock_t agbno;
|
|
xfs_extlen_t aglen;
|
|
xfs_agblock_t rbno;
|
|
xfs_extlen_t rlen;
|
|
struct xfs_bmbt_irec map;
|
|
int nmaps;
|
|
int error = 0;
|
|
|
|
ASSERT(xfs_is_reflink_inode(ip));
|
|
|
|
fbno = 0;
|
|
end = XFS_B_TO_FSB(mp, i_size_read(VFS_I(ip)));
|
|
while (end - fbno > 0) {
|
|
nmaps = 1;
|
|
/*
|
|
* Look for extents in the file. Skip holes, delalloc, or
|
|
* unwritten extents; they can't be reflinked.
|
|
*/
|
|
error = xfs_bmapi_read(ip, fbno, end - fbno, &map, &nmaps, 0);
|
|
if (error)
|
|
return error;
|
|
if (nmaps == 0)
|
|
break;
|
|
if (map.br_startblock == HOLESTARTBLOCK ||
|
|
map.br_startblock == DELAYSTARTBLOCK ||
|
|
ISUNWRITTEN(&map))
|
|
goto next;
|
|
|
|
agno = XFS_FSB_TO_AGNO(mp, map.br_startblock);
|
|
agbno = XFS_FSB_TO_AGBNO(mp, map.br_startblock);
|
|
aglen = map.br_blockcount;
|
|
|
|
error = xfs_reflink_find_shared(mp, agno, agbno, aglen,
|
|
&rbno, &rlen, false);
|
|
if (error)
|
|
return error;
|
|
/* Is there still a shared block here? */
|
|
if (rbno != NULLAGBLOCK)
|
|
return 0;
|
|
next:
|
|
fbno = map.br_startoff + map.br_blockcount;
|
|
}
|
|
|
|
/*
|
|
* We didn't find any shared blocks so turn off the reflink flag.
|
|
* First, get rid of any leftover CoW mappings.
|
|
*/
|
|
error = xfs_reflink_cancel_cow_blocks(ip, tpp, 0, NULLFILEOFF);
|
|
if (error)
|
|
return error;
|
|
|
|
/* Clear the inode flag. */
|
|
trace_xfs_reflink_unset_inode_flag(ip);
|
|
ip->i_d.di_flags2 &= ~XFS_DIFLAG2_REFLINK;
|
|
xfs_inode_clear_cowblocks_tag(ip);
|
|
xfs_trans_ijoin(*tpp, ip, 0);
|
|
xfs_trans_log_inode(*tpp, ip, XFS_ILOG_CORE);
|
|
|
|
return error;
|
|
}
|
|
|
|
/*
|
|
* Clear the inode reflink flag if there are no shared extents and the size
|
|
* hasn't changed.
|
|
*/
|
|
STATIC int
|
|
xfs_reflink_try_clear_inode_flag(
|
|
struct xfs_inode *ip)
|
|
{
|
|
struct xfs_mount *mp = ip->i_mount;
|
|
struct xfs_trans *tp;
|
|
int error = 0;
|
|
|
|
/* Start a rolling transaction to remove the mappings */
|
|
error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, 0, 0, 0, &tp);
|
|
if (error)
|
|
return error;
|
|
|
|
xfs_ilock(ip, XFS_ILOCK_EXCL);
|
|
xfs_trans_ijoin(tp, ip, 0);
|
|
|
|
error = xfs_reflink_clear_inode_flag(ip, &tp);
|
|
if (error)
|
|
goto cancel;
|
|
|
|
error = xfs_trans_commit(tp);
|
|
if (error)
|
|
goto out;
|
|
|
|
xfs_iunlock(ip, XFS_ILOCK_EXCL);
|
|
return 0;
|
|
cancel:
|
|
xfs_trans_cancel(tp);
|
|
out:
|
|
xfs_iunlock(ip, XFS_ILOCK_EXCL);
|
|
return error;
|
|
}
|
|
|
|
/*
|
|
* Pre-COW all shared blocks within a given byte range of a file and turn off
|
|
* the reflink flag if we unshare all of the file's blocks.
|
|
*/
|
|
int
|
|
xfs_reflink_unshare(
|
|
struct xfs_inode *ip,
|
|
xfs_off_t offset,
|
|
xfs_off_t len)
|
|
{
|
|
struct xfs_mount *mp = ip->i_mount;
|
|
xfs_fileoff_t fbno;
|
|
xfs_filblks_t end;
|
|
xfs_off_t isize;
|
|
int error;
|
|
|
|
if (!xfs_is_reflink_inode(ip))
|
|
return 0;
|
|
|
|
trace_xfs_reflink_unshare(ip, offset, len);
|
|
|
|
inode_dio_wait(VFS_I(ip));
|
|
|
|
/* Try to CoW the selected ranges */
|
|
xfs_ilock(ip, XFS_ILOCK_EXCL);
|
|
fbno = XFS_B_TO_FSBT(mp, offset);
|
|
isize = i_size_read(VFS_I(ip));
|
|
end = XFS_B_TO_FSB(mp, offset + len);
|
|
error = xfs_reflink_dirty_extents(ip, fbno, end, isize);
|
|
if (error)
|
|
goto out_unlock;
|
|
xfs_iunlock(ip, XFS_ILOCK_EXCL);
|
|
|
|
/* Wait for the IO to finish */
|
|
error = filemap_write_and_wait(VFS_I(ip)->i_mapping);
|
|
if (error)
|
|
goto out;
|
|
|
|
/* Turn off the reflink flag if possible. */
|
|
error = xfs_reflink_try_clear_inode_flag(ip);
|
|
if (error)
|
|
goto out;
|
|
|
|
return 0;
|
|
|
|
out_unlock:
|
|
xfs_iunlock(ip, XFS_ILOCK_EXCL);
|
|
out:
|
|
trace_xfs_reflink_unshare_error(ip, error, _RET_IP_);
|
|
return error;
|
|
}
|
|
|
|
/*
|
|
* Does this inode have any real CoW reservations?
|
|
*/
|
|
bool
|
|
xfs_reflink_has_real_cow_blocks(
|
|
struct xfs_inode *ip)
|
|
{
|
|
struct xfs_bmbt_irec irec;
|
|
struct xfs_ifork *ifp;
|
|
struct xfs_bmbt_rec_host *gotp;
|
|
xfs_extnum_t idx;
|
|
|
|
if (!xfs_is_reflink_inode(ip))
|
|
return false;
|
|
|
|
/* Go find the old extent in the CoW fork. */
|
|
ifp = XFS_IFORK_PTR(ip, XFS_COW_FORK);
|
|
gotp = xfs_iext_bno_to_ext(ifp, 0, &idx);
|
|
while (gotp) {
|
|
xfs_bmbt_get_all(gotp, &irec);
|
|
|
|
if (!isnullstartblock(irec.br_startblock))
|
|
return true;
|
|
|
|
/* Roll on... */
|
|
idx++;
|
|
if (idx >= ifp->if_bytes / sizeof(xfs_bmbt_rec_t))
|
|
break;
|
|
gotp = xfs_iext_get_ext(ifp, idx);
|
|
}
|
|
|
|
return false;
|
|
}
|