![Darrick J. Wong](/assets/img/avatar_default.png)
Rework the data flow in xfs_file_iomap_begin where we decide if we have to break shared extents. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Brian Foster <bfoster@redhat.com>
1273 lines
35 KiB
C
1273 lines
35 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (c) 2000-2006 Silicon Graphics, Inc.
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* Copyright (c) 2016-2018 Christoph Hellwig.
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* All Rights Reserved.
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*/
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#include <linux/iomap.h>
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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_inode.h"
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#include "xfs_btree.h"
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#include "xfs_bmap_btree.h"
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#include "xfs_bmap.h"
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#include "xfs_bmap_util.h"
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#include "xfs_errortag.h"
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#include "xfs_error.h"
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#include "xfs_trans.h"
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#include "xfs_trans_space.h"
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#include "xfs_inode_item.h"
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#include "xfs_iomap.h"
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#include "xfs_trace.h"
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#include "xfs_icache.h"
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#include "xfs_quota.h"
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#include "xfs_dquot_item.h"
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#include "xfs_dquot.h"
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#include "xfs_reflink.h"
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#define XFS_WRITEIO_ALIGN(mp,off) (((off) >> mp->m_writeio_log) \
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<< mp->m_writeio_log)
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static int
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xfs_alert_fsblock_zero(
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xfs_inode_t *ip,
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xfs_bmbt_irec_t *imap)
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{
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xfs_alert_tag(ip->i_mount, XFS_PTAG_FSBLOCK_ZERO,
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"Access to block zero in inode %llu "
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"start_block: %llx start_off: %llx "
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"blkcnt: %llx extent-state: %x",
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(unsigned long long)ip->i_ino,
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(unsigned long long)imap->br_startblock,
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(unsigned long long)imap->br_startoff,
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(unsigned long long)imap->br_blockcount,
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imap->br_state);
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return -EFSCORRUPTED;
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}
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int
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xfs_bmbt_to_iomap(
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struct xfs_inode *ip,
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struct iomap *iomap,
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struct xfs_bmbt_irec *imap,
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bool shared)
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{
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struct xfs_mount *mp = ip->i_mount;
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if (unlikely(!imap->br_startblock && !XFS_IS_REALTIME_INODE(ip)))
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return xfs_alert_fsblock_zero(ip, imap);
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if (imap->br_startblock == HOLESTARTBLOCK) {
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iomap->addr = IOMAP_NULL_ADDR;
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iomap->type = IOMAP_HOLE;
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} else if (imap->br_startblock == DELAYSTARTBLOCK ||
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isnullstartblock(imap->br_startblock)) {
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iomap->addr = IOMAP_NULL_ADDR;
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iomap->type = IOMAP_DELALLOC;
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} else {
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iomap->addr = BBTOB(xfs_fsb_to_db(ip, imap->br_startblock));
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if (imap->br_state == XFS_EXT_UNWRITTEN)
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iomap->type = IOMAP_UNWRITTEN;
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else
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iomap->type = IOMAP_MAPPED;
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}
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iomap->offset = XFS_FSB_TO_B(mp, imap->br_startoff);
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iomap->length = XFS_FSB_TO_B(mp, imap->br_blockcount);
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iomap->bdev = xfs_find_bdev_for_inode(VFS_I(ip));
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iomap->dax_dev = xfs_find_daxdev_for_inode(VFS_I(ip));
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if (xfs_ipincount(ip) &&
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(ip->i_itemp->ili_fsync_fields & ~XFS_ILOG_TIMESTAMP))
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iomap->flags |= IOMAP_F_DIRTY;
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if (shared)
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iomap->flags |= IOMAP_F_SHARED;
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return 0;
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}
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static void
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xfs_hole_to_iomap(
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struct xfs_inode *ip,
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struct iomap *iomap,
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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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iomap->addr = IOMAP_NULL_ADDR;
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iomap->type = IOMAP_HOLE;
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iomap->offset = XFS_FSB_TO_B(ip->i_mount, offset_fsb);
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iomap->length = XFS_FSB_TO_B(ip->i_mount, end_fsb - offset_fsb);
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iomap->bdev = xfs_find_bdev_for_inode(VFS_I(ip));
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iomap->dax_dev = xfs_find_daxdev_for_inode(VFS_I(ip));
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}
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xfs_extlen_t
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xfs_eof_alignment(
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struct xfs_inode *ip,
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xfs_extlen_t extsize)
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{
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struct xfs_mount *mp = ip->i_mount;
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xfs_extlen_t align = 0;
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if (!XFS_IS_REALTIME_INODE(ip)) {
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/*
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* Round up the allocation request to a stripe unit
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* (m_dalign) boundary if the file size is >= stripe unit
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* size, and we are allocating past the allocation eof.
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*
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* If mounted with the "-o swalloc" option the alignment is
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* increased from the strip unit size to the stripe width.
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*/
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if (mp->m_swidth && (mp->m_flags & XFS_MOUNT_SWALLOC))
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align = mp->m_swidth;
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else if (mp->m_dalign)
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align = mp->m_dalign;
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if (align && XFS_ISIZE(ip) < XFS_FSB_TO_B(mp, align))
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align = 0;
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}
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/*
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* Always round up the allocation request to an extent boundary
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* (when file on a real-time subvolume or has di_extsize hint).
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*/
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if (extsize) {
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if (align)
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align = roundup_64(align, extsize);
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else
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align = extsize;
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}
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return align;
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}
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STATIC int
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xfs_iomap_eof_align_last_fsb(
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struct xfs_inode *ip,
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xfs_extlen_t extsize,
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xfs_fileoff_t *last_fsb)
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{
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xfs_extlen_t align = xfs_eof_alignment(ip, extsize);
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if (align) {
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xfs_fileoff_t new_last_fsb = roundup_64(*last_fsb, align);
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int eof, error;
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error = xfs_bmap_eof(ip, new_last_fsb, XFS_DATA_FORK, &eof);
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if (error)
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return error;
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if (eof)
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*last_fsb = new_last_fsb;
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}
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return 0;
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}
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int
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xfs_iomap_write_direct(
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xfs_inode_t *ip,
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xfs_off_t offset,
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size_t count,
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xfs_bmbt_irec_t *imap,
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int nmaps)
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{
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xfs_mount_t *mp = ip->i_mount;
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xfs_fileoff_t offset_fsb;
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xfs_fileoff_t last_fsb;
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xfs_filblks_t count_fsb, resaligned;
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xfs_extlen_t extsz;
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int nimaps;
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int quota_flag;
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int rt;
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xfs_trans_t *tp;
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uint qblocks, resblks, resrtextents;
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int error;
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int lockmode;
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int bmapi_flags = XFS_BMAPI_PREALLOC;
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uint tflags = 0;
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rt = XFS_IS_REALTIME_INODE(ip);
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extsz = xfs_get_extsz_hint(ip);
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lockmode = XFS_ILOCK_SHARED; /* locked by caller */
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ASSERT(xfs_isilocked(ip, lockmode));
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offset_fsb = XFS_B_TO_FSBT(mp, offset);
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last_fsb = XFS_B_TO_FSB(mp, ((xfs_ufsize_t)(offset + count)));
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if ((offset + count) > XFS_ISIZE(ip)) {
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/*
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* Assert that the in-core extent list is present since this can
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* call xfs_iread_extents() and we only have the ilock shared.
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* This should be safe because the lock was held around a bmapi
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* call in the caller and we only need it to access the in-core
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* list.
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*/
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ASSERT(XFS_IFORK_PTR(ip, XFS_DATA_FORK)->if_flags &
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XFS_IFEXTENTS);
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error = xfs_iomap_eof_align_last_fsb(ip, extsz, &last_fsb);
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if (error)
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goto out_unlock;
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} else {
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if (nmaps && (imap->br_startblock == HOLESTARTBLOCK))
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last_fsb = min(last_fsb, (xfs_fileoff_t)
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imap->br_blockcount +
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imap->br_startoff);
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}
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count_fsb = last_fsb - offset_fsb;
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ASSERT(count_fsb > 0);
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resaligned = xfs_aligned_fsb_count(offset_fsb, count_fsb, extsz);
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if (unlikely(rt)) {
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resrtextents = qblocks = resaligned;
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resrtextents /= mp->m_sb.sb_rextsize;
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resblks = XFS_DIOSTRAT_SPACE_RES(mp, 0);
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quota_flag = XFS_QMOPT_RES_RTBLKS;
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} else {
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resrtextents = 0;
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resblks = qblocks = XFS_DIOSTRAT_SPACE_RES(mp, resaligned);
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quota_flag = XFS_QMOPT_RES_REGBLKS;
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}
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/*
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* Drop the shared lock acquired by the caller, attach the dquot if
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* necessary and move on to transaction setup.
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*/
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xfs_iunlock(ip, lockmode);
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error = xfs_qm_dqattach(ip);
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if (error)
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return error;
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/*
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* For DAX, we do not allocate unwritten extents, but instead we zero
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* the block before we commit the transaction. Ideally we'd like to do
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* this outside the transaction context, but if we commit and then crash
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* we may not have zeroed the blocks and this will be exposed on
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* recovery of the allocation. Hence we must zero before commit.
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*
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* Further, if we are mapping unwritten extents here, we need to zero
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* and convert them to written so that we don't need an unwritten extent
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* callback for DAX. This also means that we need to be able to dip into
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* the reserve block pool for bmbt block allocation if there is no space
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* left but we need to do unwritten extent conversion.
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*/
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if (IS_DAX(VFS_I(ip))) {
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bmapi_flags = XFS_BMAPI_CONVERT | XFS_BMAPI_ZERO;
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if (imap->br_state == XFS_EXT_UNWRITTEN) {
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tflags |= XFS_TRANS_RESERVE;
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resblks = XFS_DIOSTRAT_SPACE_RES(mp, 0) << 1;
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}
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}
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error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, resblks, resrtextents,
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tflags, &tp);
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if (error)
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return error;
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lockmode = XFS_ILOCK_EXCL;
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xfs_ilock(ip, lockmode);
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error = xfs_trans_reserve_quota_nblks(tp, ip, qblocks, 0, quota_flag);
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if (error)
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goto out_trans_cancel;
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xfs_trans_ijoin(tp, ip, 0);
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/*
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* From this point onwards we overwrite the imap pointer that the
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* caller gave to us.
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*/
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nimaps = 1;
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error = xfs_bmapi_write(tp, ip, offset_fsb, count_fsb,
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bmapi_flags, resblks, imap, &nimaps);
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if (error)
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goto out_res_cancel;
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/*
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* Complete the transaction
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*/
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error = xfs_trans_commit(tp);
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if (error)
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goto out_unlock;
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/*
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* Copy any maps to caller's array and return any error.
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*/
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if (nimaps == 0) {
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error = -ENOSPC;
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goto out_unlock;
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}
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if (!(imap->br_startblock || XFS_IS_REALTIME_INODE(ip)))
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error = xfs_alert_fsblock_zero(ip, imap);
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out_unlock:
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xfs_iunlock(ip, lockmode);
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return error;
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out_res_cancel:
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xfs_trans_unreserve_quota_nblks(tp, ip, (long)qblocks, 0, quota_flag);
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out_trans_cancel:
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xfs_trans_cancel(tp);
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goto out_unlock;
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}
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STATIC bool
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xfs_quota_need_throttle(
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struct xfs_inode *ip,
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int type,
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xfs_fsblock_t alloc_blocks)
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{
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struct xfs_dquot *dq = xfs_inode_dquot(ip, type);
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if (!dq || !xfs_this_quota_on(ip->i_mount, type))
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return false;
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/* no hi watermark, no throttle */
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if (!dq->q_prealloc_hi_wmark)
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return false;
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/* under the lo watermark, no throttle */
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if (dq->q_res_bcount + alloc_blocks < dq->q_prealloc_lo_wmark)
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return false;
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return true;
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}
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STATIC void
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xfs_quota_calc_throttle(
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struct xfs_inode *ip,
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int type,
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xfs_fsblock_t *qblocks,
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int *qshift,
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int64_t *qfreesp)
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{
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int64_t freesp;
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int shift = 0;
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struct xfs_dquot *dq = xfs_inode_dquot(ip, type);
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/* no dq, or over hi wmark, squash the prealloc completely */
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if (!dq || dq->q_res_bcount >= dq->q_prealloc_hi_wmark) {
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*qblocks = 0;
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*qfreesp = 0;
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return;
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}
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freesp = dq->q_prealloc_hi_wmark - dq->q_res_bcount;
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if (freesp < dq->q_low_space[XFS_QLOWSP_5_PCNT]) {
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shift = 2;
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if (freesp < dq->q_low_space[XFS_QLOWSP_3_PCNT])
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shift += 2;
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if (freesp < dq->q_low_space[XFS_QLOWSP_1_PCNT])
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shift += 2;
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}
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if (freesp < *qfreesp)
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*qfreesp = freesp;
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/* only overwrite the throttle values if we are more aggressive */
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if ((freesp >> shift) < (*qblocks >> *qshift)) {
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*qblocks = freesp;
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*qshift = shift;
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}
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}
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/*
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* If we are doing a write at the end of the file and there are no allocations
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* past this one, then extend the allocation out to the file system's write
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* iosize.
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*
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* If we don't have a user specified preallocation size, dynamically increase
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* the preallocation size as the size of the file grows. Cap the maximum size
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* at a single extent or less if the filesystem is near full. The closer the
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* filesystem is to full, the smaller the maximum prealocation.
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*
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* As an exception we don't do any preallocation at all if the file is smaller
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* than the minimum preallocation and we are using the default dynamic
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* preallocation scheme, as it is likely this is the only write to the file that
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* is going to be done.
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*
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* We clean up any extra space left over when the file is closed in
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* xfs_inactive().
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*/
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STATIC xfs_fsblock_t
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xfs_iomap_prealloc_size(
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struct xfs_inode *ip,
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int whichfork,
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loff_t offset,
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loff_t count,
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struct xfs_iext_cursor *icur)
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{
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struct xfs_mount *mp = ip->i_mount;
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struct xfs_ifork *ifp = XFS_IFORK_PTR(ip, whichfork);
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xfs_fileoff_t offset_fsb = XFS_B_TO_FSBT(mp, offset);
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struct xfs_bmbt_irec prev;
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int shift = 0;
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int64_t freesp;
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xfs_fsblock_t qblocks;
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int qshift = 0;
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xfs_fsblock_t alloc_blocks = 0;
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if (offset + count <= XFS_ISIZE(ip))
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return 0;
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if (!(mp->m_flags & XFS_MOUNT_DFLT_IOSIZE) &&
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(XFS_ISIZE(ip) < XFS_FSB_TO_B(mp, mp->m_writeio_blocks)))
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return 0;
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/*
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* If an explicit allocsize is set, the file is small, or we
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* are writing behind a hole, then use the minimum prealloc:
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*/
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if ((mp->m_flags & XFS_MOUNT_DFLT_IOSIZE) ||
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XFS_ISIZE(ip) < XFS_FSB_TO_B(mp, mp->m_dalign) ||
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!xfs_iext_peek_prev_extent(ifp, icur, &prev) ||
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prev.br_startoff + prev.br_blockcount < offset_fsb)
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return mp->m_writeio_blocks;
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/*
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* Determine the initial size of the preallocation. We are beyond the
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* current EOF here, but we need to take into account whether this is
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* a sparse write or an extending write when determining the
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* preallocation size. Hence we need to look up the extent that ends
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* at the current write offset and use the result to determine the
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* preallocation size.
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*
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* If the extent is a hole, then preallocation is essentially disabled.
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* Otherwise we take the size of the preceding data extent as the basis
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* for the preallocation size. If the size of the extent is greater than
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* half the maximum extent length, then use the current offset as the
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* basis. This ensures that for large files the preallocation size
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* always extends to MAXEXTLEN rather than falling short due to things
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* like stripe unit/width alignment of real extents.
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*/
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if (prev.br_blockcount <= (MAXEXTLEN >> 1))
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alloc_blocks = prev.br_blockcount << 1;
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else
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alloc_blocks = XFS_B_TO_FSB(mp, offset);
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if (!alloc_blocks)
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goto check_writeio;
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qblocks = alloc_blocks;
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/*
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* MAXEXTLEN is not a power of two value but we round the prealloc down
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* to the nearest power of two value after throttling. To prevent the
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* round down from unconditionally reducing the maximum supported prealloc
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* size, we round up first, apply appropriate throttling, round down and
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* cap the value to MAXEXTLEN.
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*/
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alloc_blocks = XFS_FILEOFF_MIN(roundup_pow_of_two(MAXEXTLEN),
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alloc_blocks);
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|
|
freesp = percpu_counter_read_positive(&mp->m_fdblocks);
|
|
if (freesp < mp->m_low_space[XFS_LOWSP_5_PCNT]) {
|
|
shift = 2;
|
|
if (freesp < mp->m_low_space[XFS_LOWSP_4_PCNT])
|
|
shift++;
|
|
if (freesp < mp->m_low_space[XFS_LOWSP_3_PCNT])
|
|
shift++;
|
|
if (freesp < mp->m_low_space[XFS_LOWSP_2_PCNT])
|
|
shift++;
|
|
if (freesp < mp->m_low_space[XFS_LOWSP_1_PCNT])
|
|
shift++;
|
|
}
|
|
|
|
/*
|
|
* Check each quota to cap the prealloc size, provide a shift value to
|
|
* throttle with and adjust amount of available space.
|
|
*/
|
|
if (xfs_quota_need_throttle(ip, XFS_DQ_USER, alloc_blocks))
|
|
xfs_quota_calc_throttle(ip, XFS_DQ_USER, &qblocks, &qshift,
|
|
&freesp);
|
|
if (xfs_quota_need_throttle(ip, XFS_DQ_GROUP, alloc_blocks))
|
|
xfs_quota_calc_throttle(ip, XFS_DQ_GROUP, &qblocks, &qshift,
|
|
&freesp);
|
|
if (xfs_quota_need_throttle(ip, XFS_DQ_PROJ, alloc_blocks))
|
|
xfs_quota_calc_throttle(ip, XFS_DQ_PROJ, &qblocks, &qshift,
|
|
&freesp);
|
|
|
|
/*
|
|
* The final prealloc size is set to the minimum of free space available
|
|
* in each of the quotas and the overall filesystem.
|
|
*
|
|
* The shift throttle value is set to the maximum value as determined by
|
|
* the global low free space values and per-quota low free space values.
|
|
*/
|
|
alloc_blocks = min(alloc_blocks, qblocks);
|
|
shift = max(shift, qshift);
|
|
|
|
if (shift)
|
|
alloc_blocks >>= shift;
|
|
/*
|
|
* rounddown_pow_of_two() returns an undefined result if we pass in
|
|
* alloc_blocks = 0.
|
|
*/
|
|
if (alloc_blocks)
|
|
alloc_blocks = rounddown_pow_of_two(alloc_blocks);
|
|
if (alloc_blocks > MAXEXTLEN)
|
|
alloc_blocks = MAXEXTLEN;
|
|
|
|
/*
|
|
* If we are still trying to allocate more space than is
|
|
* available, squash the prealloc hard. This can happen if we
|
|
* have a large file on a small filesystem and the above
|
|
* lowspace thresholds are smaller than MAXEXTLEN.
|
|
*/
|
|
while (alloc_blocks && alloc_blocks >= freesp)
|
|
alloc_blocks >>= 4;
|
|
check_writeio:
|
|
if (alloc_blocks < mp->m_writeio_blocks)
|
|
alloc_blocks = mp->m_writeio_blocks;
|
|
trace_xfs_iomap_prealloc_size(ip, alloc_blocks, shift,
|
|
mp->m_writeio_blocks);
|
|
return alloc_blocks;
|
|
}
|
|
|
|
static int
|
|
xfs_file_iomap_begin_delay(
|
|
struct inode *inode,
|
|
loff_t offset,
|
|
loff_t count,
|
|
unsigned flags,
|
|
struct iomap *iomap)
|
|
{
|
|
struct xfs_inode *ip = XFS_I(inode);
|
|
struct xfs_mount *mp = ip->i_mount;
|
|
xfs_fileoff_t offset_fsb = XFS_B_TO_FSBT(mp, offset);
|
|
xfs_fileoff_t maxbytes_fsb =
|
|
XFS_B_TO_FSB(mp, mp->m_super->s_maxbytes);
|
|
xfs_fileoff_t end_fsb;
|
|
struct xfs_bmbt_irec imap, cmap;
|
|
struct xfs_iext_cursor icur, ccur;
|
|
xfs_fsblock_t prealloc_blocks = 0;
|
|
bool eof = false, cow_eof = false, shared = false;
|
|
int whichfork = XFS_DATA_FORK;
|
|
int error = 0;
|
|
|
|
ASSERT(!XFS_IS_REALTIME_INODE(ip));
|
|
ASSERT(!xfs_get_extsz_hint(ip));
|
|
|
|
xfs_ilock(ip, XFS_ILOCK_EXCL);
|
|
|
|
if (unlikely(XFS_TEST_ERROR(
|
|
(XFS_IFORK_FORMAT(ip, XFS_DATA_FORK) != XFS_DINODE_FMT_EXTENTS &&
|
|
XFS_IFORK_FORMAT(ip, XFS_DATA_FORK) != XFS_DINODE_FMT_BTREE),
|
|
mp, XFS_ERRTAG_BMAPIFORMAT))) {
|
|
XFS_ERROR_REPORT(__func__, XFS_ERRLEVEL_LOW, mp);
|
|
error = -EFSCORRUPTED;
|
|
goto out_unlock;
|
|
}
|
|
|
|
XFS_STATS_INC(mp, xs_blk_mapw);
|
|
|
|
if (!(ip->i_df.if_flags & XFS_IFEXTENTS)) {
|
|
error = xfs_iread_extents(NULL, ip, XFS_DATA_FORK);
|
|
if (error)
|
|
goto out_unlock;
|
|
}
|
|
|
|
end_fsb = min(XFS_B_TO_FSB(mp, offset + count), maxbytes_fsb);
|
|
|
|
/*
|
|
* Search the data fork fork first to look up our source mapping. We
|
|
* always need the data fork map, as we have to return it to the
|
|
* iomap code so that the higher level write code can read data in to
|
|
* perform read-modify-write cycles for unaligned writes.
|
|
*/
|
|
eof = !xfs_iext_lookup_extent(ip, &ip->i_df, offset_fsb, &icur, &imap);
|
|
if (eof)
|
|
imap.br_startoff = end_fsb; /* fake hole until the end */
|
|
|
|
/* We never need to allocate blocks for zeroing a hole. */
|
|
if ((flags & IOMAP_ZERO) && imap.br_startoff > offset_fsb) {
|
|
xfs_hole_to_iomap(ip, iomap, offset_fsb, imap.br_startoff);
|
|
goto out_unlock;
|
|
}
|
|
|
|
/*
|
|
* Search the COW fork extent list even if we did not find a data fork
|
|
* extent. This serves two purposes: first this implements the
|
|
* speculative preallocation using cowextsize, so that we also unshare
|
|
* 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.
|
|
*/
|
|
if (xfs_is_cow_inode(ip)) {
|
|
if (!ip->i_cowfp) {
|
|
ASSERT(!xfs_is_reflink_inode(ip));
|
|
xfs_ifork_init_cow(ip);
|
|
}
|
|
cow_eof = !xfs_iext_lookup_extent(ip, ip->i_cowfp, offset_fsb,
|
|
&ccur, &cmap);
|
|
if (!cow_eof && cmap.br_startoff <= offset_fsb) {
|
|
trace_xfs_reflink_cow_found(ip, &cmap);
|
|
whichfork = XFS_COW_FORK;
|
|
goto done;
|
|
}
|
|
}
|
|
|
|
if (imap.br_startoff <= offset_fsb) {
|
|
/*
|
|
* For reflink files we may need a delalloc reservation when
|
|
* overwriting shared extents. This includes zeroing of
|
|
* existing extents that contain data.
|
|
*/
|
|
if (!xfs_is_cow_inode(ip) ||
|
|
((flags & IOMAP_ZERO) && imap.br_state != XFS_EXT_NORM)) {
|
|
trace_xfs_iomap_found(ip, offset, count, XFS_DATA_FORK,
|
|
&imap);
|
|
goto done;
|
|
}
|
|
|
|
xfs_trim_extent(&imap, offset_fsb, end_fsb - offset_fsb);
|
|
|
|
/* Trim the mapping to the nearest shared extent boundary. */
|
|
error = xfs_inode_need_cow(ip, &imap, &shared);
|
|
if (error)
|
|
goto out_unlock;
|
|
|
|
/* Not shared? Just report the (potentially capped) extent. */
|
|
if (!shared) {
|
|
trace_xfs_iomap_found(ip, offset, count, XFS_DATA_FORK,
|
|
&imap);
|
|
goto done;
|
|
}
|
|
|
|
/*
|
|
* Fork all the shared blocks from our write offset until the
|
|
* end of the extent.
|
|
*/
|
|
whichfork = XFS_COW_FORK;
|
|
end_fsb = imap.br_startoff + imap.br_blockcount;
|
|
} else {
|
|
/*
|
|
* We cap the maximum length we map here to MAX_WRITEBACK_PAGES
|
|
* pages to keep the chunks of work done where somewhat
|
|
* symmetric with the work writeback does. This is a completely
|
|
* arbitrary number pulled out of thin air.
|
|
*
|
|
* Note that the values needs to be less than 32-bits wide until
|
|
* the lower level functions are updated.
|
|
*/
|
|
count = min_t(loff_t, count, 1024 * PAGE_SIZE);
|
|
end_fsb = min(XFS_B_TO_FSB(mp, offset + count), maxbytes_fsb);
|
|
|
|
if (xfs_is_always_cow_inode(ip))
|
|
whichfork = XFS_COW_FORK;
|
|
}
|
|
|
|
error = xfs_qm_dqattach_locked(ip, false);
|
|
if (error)
|
|
goto out_unlock;
|
|
|
|
if (eof) {
|
|
prealloc_blocks = xfs_iomap_prealloc_size(ip, whichfork, offset,
|
|
count, &icur);
|
|
if (prealloc_blocks) {
|
|
xfs_extlen_t align;
|
|
xfs_off_t end_offset;
|
|
xfs_fileoff_t p_end_fsb;
|
|
|
|
end_offset = XFS_WRITEIO_ALIGN(mp, offset + count - 1);
|
|
p_end_fsb = XFS_B_TO_FSBT(mp, end_offset) +
|
|
prealloc_blocks;
|
|
|
|
align = xfs_eof_alignment(ip, 0);
|
|
if (align)
|
|
p_end_fsb = roundup_64(p_end_fsb, align);
|
|
|
|
p_end_fsb = min(p_end_fsb, maxbytes_fsb);
|
|
ASSERT(p_end_fsb > offset_fsb);
|
|
prealloc_blocks = p_end_fsb - end_fsb;
|
|
}
|
|
}
|
|
|
|
retry:
|
|
error = xfs_bmapi_reserve_delalloc(ip, whichfork, offset_fsb,
|
|
end_fsb - offset_fsb, prealloc_blocks,
|
|
whichfork == XFS_DATA_FORK ? &imap : &cmap,
|
|
whichfork == XFS_DATA_FORK ? &icur : &ccur,
|
|
whichfork == XFS_DATA_FORK ? eof : cow_eof);
|
|
switch (error) {
|
|
case 0:
|
|
break;
|
|
case -ENOSPC:
|
|
case -EDQUOT:
|
|
/* retry without any preallocation */
|
|
trace_xfs_delalloc_enospc(ip, offset, count);
|
|
if (prealloc_blocks) {
|
|
prealloc_blocks = 0;
|
|
goto retry;
|
|
}
|
|
/*FALLTHRU*/
|
|
default:
|
|
goto out_unlock;
|
|
}
|
|
|
|
/*
|
|
* Flag newly allocated delalloc blocks with IOMAP_F_NEW so we punch
|
|
* them out if the write happens to fail.
|
|
*/
|
|
iomap->flags |= IOMAP_F_NEW;
|
|
trace_xfs_iomap_alloc(ip, offset, count, whichfork,
|
|
whichfork == XFS_DATA_FORK ? &imap : &cmap);
|
|
done:
|
|
if (whichfork == XFS_COW_FORK) {
|
|
if (imap.br_startoff > offset_fsb) {
|
|
xfs_trim_extent(&cmap, offset_fsb,
|
|
imap.br_startoff - offset_fsb);
|
|
error = xfs_bmbt_to_iomap(ip, iomap, &cmap, true);
|
|
goto out_unlock;
|
|
}
|
|
/* ensure we only report blocks we have a reservation for */
|
|
xfs_trim_extent(&imap, cmap.br_startoff, cmap.br_blockcount);
|
|
shared = true;
|
|
}
|
|
error = xfs_bmbt_to_iomap(ip, iomap, &imap, shared);
|
|
out_unlock:
|
|
xfs_iunlock(ip, XFS_ILOCK_EXCL);
|
|
return error;
|
|
}
|
|
|
|
int
|
|
xfs_iomap_write_unwritten(
|
|
xfs_inode_t *ip,
|
|
xfs_off_t offset,
|
|
xfs_off_t count,
|
|
bool update_isize)
|
|
{
|
|
xfs_mount_t *mp = ip->i_mount;
|
|
xfs_fileoff_t offset_fsb;
|
|
xfs_filblks_t count_fsb;
|
|
xfs_filblks_t numblks_fsb;
|
|
int nimaps;
|
|
xfs_trans_t *tp;
|
|
xfs_bmbt_irec_t imap;
|
|
struct inode *inode = VFS_I(ip);
|
|
xfs_fsize_t i_size;
|
|
uint resblks;
|
|
int error;
|
|
|
|
trace_xfs_unwritten_convert(ip, offset, count);
|
|
|
|
offset_fsb = XFS_B_TO_FSBT(mp, offset);
|
|
count_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)offset + count);
|
|
count_fsb = (xfs_filblks_t)(count_fsb - offset_fsb);
|
|
|
|
/*
|
|
* Reserve enough blocks in this transaction for two complete extent
|
|
* btree splits. We may be converting the middle part of an unwritten
|
|
* extent and in this case we will insert two new extents in the btree
|
|
* each of which could cause a full split.
|
|
*
|
|
* This reservation amount will be used in the first call to
|
|
* xfs_bmbt_split() to select an AG with enough space to satisfy the
|
|
* rest of the operation.
|
|
*/
|
|
resblks = XFS_DIOSTRAT_SPACE_RES(mp, 0) << 1;
|
|
|
|
do {
|
|
/*
|
|
* Set up a transaction to convert the range of extents
|
|
* from unwritten to real. Do allocations in a loop until
|
|
* we have covered the range passed in.
|
|
*
|
|
* Note that we can't risk to recursing back into the filesystem
|
|
* here as we might be asked to write out the same inode that we
|
|
* complete here and might deadlock on the iolock.
|
|
*/
|
|
error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, resblks, 0,
|
|
XFS_TRANS_RESERVE | XFS_TRANS_NOFS, &tp);
|
|
if (error)
|
|
return error;
|
|
|
|
xfs_ilock(ip, XFS_ILOCK_EXCL);
|
|
xfs_trans_ijoin(tp, ip, 0);
|
|
|
|
/*
|
|
* Modify the unwritten extent state of the buffer.
|
|
*/
|
|
nimaps = 1;
|
|
error = xfs_bmapi_write(tp, ip, offset_fsb, count_fsb,
|
|
XFS_BMAPI_CONVERT, resblks, &imap,
|
|
&nimaps);
|
|
if (error)
|
|
goto error_on_bmapi_transaction;
|
|
|
|
/*
|
|
* Log the updated inode size as we go. We have to be careful
|
|
* to only log it up to the actual write offset if it is
|
|
* halfway into a block.
|
|
*/
|
|
i_size = XFS_FSB_TO_B(mp, offset_fsb + count_fsb);
|
|
if (i_size > offset + count)
|
|
i_size = offset + count;
|
|
if (update_isize && i_size > i_size_read(inode))
|
|
i_size_write(inode, i_size);
|
|
i_size = xfs_new_eof(ip, i_size);
|
|
if (i_size) {
|
|
ip->i_d.di_size = i_size;
|
|
xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
|
|
}
|
|
|
|
error = xfs_trans_commit(tp);
|
|
xfs_iunlock(ip, XFS_ILOCK_EXCL);
|
|
if (error)
|
|
return error;
|
|
|
|
if (!(imap.br_startblock || XFS_IS_REALTIME_INODE(ip)))
|
|
return xfs_alert_fsblock_zero(ip, &imap);
|
|
|
|
if ((numblks_fsb = imap.br_blockcount) == 0) {
|
|
/*
|
|
* The numblks_fsb value should always get
|
|
* smaller, otherwise the loop is stuck.
|
|
*/
|
|
ASSERT(imap.br_blockcount);
|
|
break;
|
|
}
|
|
offset_fsb += numblks_fsb;
|
|
count_fsb -= numblks_fsb;
|
|
} while (count_fsb > 0);
|
|
|
|
return 0;
|
|
|
|
error_on_bmapi_transaction:
|
|
xfs_trans_cancel(tp);
|
|
xfs_iunlock(ip, XFS_ILOCK_EXCL);
|
|
return error;
|
|
}
|
|
|
|
static inline bool
|
|
imap_needs_alloc(
|
|
struct inode *inode,
|
|
struct xfs_bmbt_irec *imap,
|
|
int nimaps)
|
|
{
|
|
return !nimaps ||
|
|
imap->br_startblock == HOLESTARTBLOCK ||
|
|
imap->br_startblock == DELAYSTARTBLOCK ||
|
|
(IS_DAX(inode) && imap->br_state == XFS_EXT_UNWRITTEN);
|
|
}
|
|
|
|
static inline bool
|
|
needs_cow_for_zeroing(
|
|
struct xfs_bmbt_irec *imap,
|
|
int nimaps)
|
|
{
|
|
return nimaps &&
|
|
imap->br_startblock != HOLESTARTBLOCK &&
|
|
imap->br_state != XFS_EXT_UNWRITTEN;
|
|
}
|
|
|
|
static int
|
|
xfs_ilock_for_iomap(
|
|
struct xfs_inode *ip,
|
|
unsigned flags,
|
|
unsigned *lockmode)
|
|
{
|
|
unsigned mode = XFS_ILOCK_SHARED;
|
|
bool is_write = flags & (IOMAP_WRITE | IOMAP_ZERO);
|
|
|
|
/*
|
|
* COW writes may allocate delalloc space or convert unwritten COW
|
|
* extents, so we need to make sure to take the lock exclusively here.
|
|
*/
|
|
if (xfs_is_cow_inode(ip) && is_write) {
|
|
/*
|
|
* FIXME: It could still overwrite on unshared extents and not
|
|
* need allocation.
|
|
*/
|
|
if (flags & IOMAP_NOWAIT)
|
|
return -EAGAIN;
|
|
mode = XFS_ILOCK_EXCL;
|
|
}
|
|
|
|
/*
|
|
* Extents not yet cached requires exclusive access, don't block. This
|
|
* is an opencoded xfs_ilock_data_map_shared() call but with
|
|
* non-blocking behaviour.
|
|
*/
|
|
if (!(ip->i_df.if_flags & XFS_IFEXTENTS)) {
|
|
if (flags & IOMAP_NOWAIT)
|
|
return -EAGAIN;
|
|
mode = XFS_ILOCK_EXCL;
|
|
}
|
|
|
|
relock:
|
|
if (flags & IOMAP_NOWAIT) {
|
|
if (!xfs_ilock_nowait(ip, mode))
|
|
return -EAGAIN;
|
|
} else {
|
|
xfs_ilock(ip, mode);
|
|
}
|
|
|
|
/*
|
|
* The reflink iflag could have changed since the earlier unlocked
|
|
* check, so if we got ILOCK_SHARED for a write and but we're now a
|
|
* reflink inode we have to switch to ILOCK_EXCL and relock.
|
|
*/
|
|
if (mode == XFS_ILOCK_SHARED && is_write && xfs_is_cow_inode(ip)) {
|
|
xfs_iunlock(ip, mode);
|
|
mode = XFS_ILOCK_EXCL;
|
|
goto relock;
|
|
}
|
|
|
|
*lockmode = mode;
|
|
return 0;
|
|
}
|
|
|
|
static int
|
|
xfs_file_iomap_begin(
|
|
struct inode *inode,
|
|
loff_t offset,
|
|
loff_t length,
|
|
unsigned flags,
|
|
struct iomap *iomap)
|
|
{
|
|
struct xfs_inode *ip = XFS_I(inode);
|
|
struct xfs_mount *mp = ip->i_mount;
|
|
struct xfs_bmbt_irec imap;
|
|
xfs_fileoff_t offset_fsb, end_fsb;
|
|
int nimaps = 1, error = 0;
|
|
bool shared = false;
|
|
unsigned lockmode;
|
|
|
|
if (XFS_FORCED_SHUTDOWN(mp))
|
|
return -EIO;
|
|
|
|
if ((flags & (IOMAP_WRITE | IOMAP_ZERO)) && !(flags & IOMAP_DIRECT) &&
|
|
!IS_DAX(inode) && !xfs_get_extsz_hint(ip)) {
|
|
/* Reserve delalloc blocks for regular writeback. */
|
|
return xfs_file_iomap_begin_delay(inode, offset, length, flags,
|
|
iomap);
|
|
}
|
|
|
|
/*
|
|
* Lock the inode in the manner required for the specified operation and
|
|
* check for as many conditions that would result in blocking as
|
|
* possible. This removes most of the non-blocking checks from the
|
|
* mapping code below.
|
|
*/
|
|
error = xfs_ilock_for_iomap(ip, flags, &lockmode);
|
|
if (error)
|
|
return error;
|
|
|
|
ASSERT(offset <= mp->m_super->s_maxbytes);
|
|
if (offset > mp->m_super->s_maxbytes - length)
|
|
length = mp->m_super->s_maxbytes - offset;
|
|
offset_fsb = XFS_B_TO_FSBT(mp, offset);
|
|
end_fsb = XFS_B_TO_FSB(mp, offset + length);
|
|
|
|
error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb, &imap,
|
|
&nimaps, 0);
|
|
if (error)
|
|
goto out_unlock;
|
|
|
|
if (flags & IOMAP_REPORT) {
|
|
/* Trim the mapping to the nearest shared extent boundary. */
|
|
error = xfs_reflink_trim_around_shared(ip, &imap, &shared);
|
|
if (error)
|
|
goto out_unlock;
|
|
}
|
|
|
|
/* Non-modifying mapping requested, so we are done */
|
|
if (!(flags & (IOMAP_WRITE | IOMAP_ZERO)))
|
|
goto out_found;
|
|
|
|
/*
|
|
* Break shared extents if necessary. Checks for non-blocking IO have
|
|
* been done up front, so we don't need to do them here.
|
|
*/
|
|
if (xfs_is_cow_inode(ip)) {
|
|
struct xfs_bmbt_irec cmap;
|
|
bool directio = (flags & IOMAP_DIRECT);
|
|
|
|
/* if zeroing doesn't need COW allocation, then we are done. */
|
|
if ((flags & IOMAP_ZERO) &&
|
|
!needs_cow_for_zeroing(&imap, nimaps))
|
|
goto out_found;
|
|
|
|
/* may drop and re-acquire the ilock */
|
|
cmap = imap;
|
|
error = xfs_reflink_allocate_cow(ip, &cmap, &shared, &lockmode,
|
|
directio);
|
|
if (error)
|
|
goto out_unlock;
|
|
|
|
/*
|
|
* For buffered writes we need to report the address of the
|
|
* previous block (if there was any) so that the higher level
|
|
* write code can perform read-modify-write operations; we
|
|
* won't need the CoW fork mapping until writeback. For direct
|
|
* I/O, which must be block aligned, we need to report the
|
|
* newly allocated address. If the data fork has a hole, copy
|
|
* the COW fork mapping to avoid allocating to the data fork.
|
|
*/
|
|
if (directio || imap.br_startblock == HOLESTARTBLOCK)
|
|
imap = cmap;
|
|
|
|
end_fsb = imap.br_startoff + imap.br_blockcount;
|
|
length = XFS_FSB_TO_B(mp, end_fsb) - offset;
|
|
}
|
|
|
|
/* Don't need to allocate over holes when doing zeroing operations. */
|
|
if (flags & IOMAP_ZERO)
|
|
goto out_found;
|
|
|
|
if (!imap_needs_alloc(inode, &imap, nimaps))
|
|
goto out_found;
|
|
|
|
/* If nowait is set bail since we are going to make allocations. */
|
|
if (flags & IOMAP_NOWAIT) {
|
|
error = -EAGAIN;
|
|
goto out_unlock;
|
|
}
|
|
|
|
/*
|
|
* We cap the maximum length we map to a sane size to keep the chunks
|
|
* of work done where somewhat symmetric with the work writeback does.
|
|
* This is a completely arbitrary number pulled out of thin air as a
|
|
* best guess for initial testing.
|
|
*
|
|
* Note that the values needs to be less than 32-bits wide until the
|
|
* lower level functions are updated.
|
|
*/
|
|
length = min_t(loff_t, length, 1024 * PAGE_SIZE);
|
|
|
|
/*
|
|
* 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 (error)
|
|
return error;
|
|
|
|
iomap->flags |= IOMAP_F_NEW;
|
|
trace_xfs_iomap_alloc(ip, offset, length, XFS_DATA_FORK, &imap);
|
|
|
|
out_finish:
|
|
return xfs_bmbt_to_iomap(ip, iomap, &imap, shared);
|
|
|
|
out_found:
|
|
ASSERT(nimaps);
|
|
xfs_iunlock(ip, lockmode);
|
|
trace_xfs_iomap_found(ip, offset, length, XFS_DATA_FORK, &imap);
|
|
goto out_finish;
|
|
|
|
out_unlock:
|
|
xfs_iunlock(ip, lockmode);
|
|
return error;
|
|
}
|
|
|
|
static int
|
|
xfs_file_iomap_end_delalloc(
|
|
struct xfs_inode *ip,
|
|
loff_t offset,
|
|
loff_t length,
|
|
ssize_t written,
|
|
struct iomap *iomap)
|
|
{
|
|
struct xfs_mount *mp = ip->i_mount;
|
|
xfs_fileoff_t start_fsb;
|
|
xfs_fileoff_t end_fsb;
|
|
int error = 0;
|
|
|
|
/*
|
|
* Behave as if the write failed if drop writes is enabled. Set the NEW
|
|
* flag to force delalloc cleanup.
|
|
*/
|
|
if (XFS_TEST_ERROR(false, mp, XFS_ERRTAG_DROP_WRITES)) {
|
|
iomap->flags |= IOMAP_F_NEW;
|
|
written = 0;
|
|
}
|
|
|
|
/*
|
|
* start_fsb refers to the first unused block after a short write. If
|
|
* nothing was written, round offset down to point at the first block in
|
|
* the range.
|
|
*/
|
|
if (unlikely(!written))
|
|
start_fsb = XFS_B_TO_FSBT(mp, offset);
|
|
else
|
|
start_fsb = XFS_B_TO_FSB(mp, offset + written);
|
|
end_fsb = XFS_B_TO_FSB(mp, offset + length);
|
|
|
|
/*
|
|
* Trim delalloc blocks if they were allocated by this write and we
|
|
* didn't manage to write the whole range.
|
|
*
|
|
* We don't need to care about racing delalloc as we hold i_mutex
|
|
* across the reserve/allocate/unreserve calls. If there are delalloc
|
|
* blocks in the range, they are ours.
|
|
*/
|
|
if ((iomap->flags & IOMAP_F_NEW) && start_fsb < end_fsb) {
|
|
truncate_pagecache_range(VFS_I(ip), XFS_FSB_TO_B(mp, start_fsb),
|
|
XFS_FSB_TO_B(mp, end_fsb) - 1);
|
|
|
|
error = xfs_bmap_punch_delalloc_range(ip, start_fsb,
|
|
end_fsb - start_fsb);
|
|
if (error && !XFS_FORCED_SHUTDOWN(mp)) {
|
|
xfs_alert(mp, "%s: unable to clean up ino %lld",
|
|
__func__, ip->i_ino);
|
|
return error;
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int
|
|
xfs_file_iomap_end(
|
|
struct inode *inode,
|
|
loff_t offset,
|
|
loff_t length,
|
|
ssize_t written,
|
|
unsigned flags,
|
|
struct iomap *iomap)
|
|
{
|
|
if ((flags & IOMAP_WRITE) && iomap->type == IOMAP_DELALLOC)
|
|
return xfs_file_iomap_end_delalloc(XFS_I(inode), offset,
|
|
length, written, iomap);
|
|
return 0;
|
|
}
|
|
|
|
const struct iomap_ops xfs_iomap_ops = {
|
|
.iomap_begin = xfs_file_iomap_begin,
|
|
.iomap_end = xfs_file_iomap_end,
|
|
};
|
|
|
|
static int
|
|
xfs_seek_iomap_begin(
|
|
struct inode *inode,
|
|
loff_t offset,
|
|
loff_t length,
|
|
unsigned flags,
|
|
struct iomap *iomap)
|
|
{
|
|
struct xfs_inode *ip = XFS_I(inode);
|
|
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 + length);
|
|
xfs_fileoff_t cow_fsb = NULLFILEOFF, data_fsb = NULLFILEOFF;
|
|
struct xfs_iext_cursor icur;
|
|
struct xfs_bmbt_irec imap, cmap;
|
|
int error = 0;
|
|
unsigned lockmode;
|
|
|
|
if (XFS_FORCED_SHUTDOWN(mp))
|
|
return -EIO;
|
|
|
|
lockmode = xfs_ilock_data_map_shared(ip);
|
|
if (!(ip->i_df.if_flags & XFS_IFEXTENTS)) {
|
|
error = xfs_iread_extents(NULL, ip, XFS_DATA_FORK);
|
|
if (error)
|
|
goto out_unlock;
|
|
}
|
|
|
|
if (xfs_iext_lookup_extent(ip, &ip->i_df, offset_fsb, &icur, &imap)) {
|
|
/*
|
|
* If we found a data extent we are done.
|
|
*/
|
|
if (imap.br_startoff <= offset_fsb)
|
|
goto done;
|
|
data_fsb = imap.br_startoff;
|
|
} else {
|
|
/*
|
|
* Fake a hole until the end of the file.
|
|
*/
|
|
data_fsb = min(XFS_B_TO_FSB(mp, offset + length),
|
|
XFS_B_TO_FSB(mp, mp->m_super->s_maxbytes));
|
|
}
|
|
|
|
/*
|
|
* If a COW fork extent covers the hole, report it - capped to the next
|
|
* data fork extent:
|
|
*/
|
|
if (xfs_inode_has_cow_data(ip) &&
|
|
xfs_iext_lookup_extent(ip, ip->i_cowfp, offset_fsb, &icur, &cmap))
|
|
cow_fsb = cmap.br_startoff;
|
|
if (cow_fsb != NULLFILEOFF && cow_fsb <= offset_fsb) {
|
|
if (data_fsb < cow_fsb + cmap.br_blockcount)
|
|
end_fsb = min(end_fsb, data_fsb);
|
|
xfs_trim_extent(&cmap, offset_fsb, end_fsb);
|
|
error = xfs_bmbt_to_iomap(ip, iomap, &cmap, true);
|
|
/*
|
|
* This is a COW extent, so we must probe the page cache
|
|
* because there could be dirty page cache being backed
|
|
* by this extent.
|
|
*/
|
|
iomap->type = IOMAP_UNWRITTEN;
|
|
goto out_unlock;
|
|
}
|
|
|
|
/*
|
|
* Else report a hole, capped to the next found data or COW extent.
|
|
*/
|
|
if (cow_fsb != NULLFILEOFF && cow_fsb < data_fsb)
|
|
imap.br_blockcount = cow_fsb - offset_fsb;
|
|
else
|
|
imap.br_blockcount = data_fsb - offset_fsb;
|
|
imap.br_startoff = offset_fsb;
|
|
imap.br_startblock = HOLESTARTBLOCK;
|
|
imap.br_state = XFS_EXT_NORM;
|
|
done:
|
|
xfs_trim_extent(&imap, offset_fsb, end_fsb);
|
|
error = xfs_bmbt_to_iomap(ip, iomap, &imap, false);
|
|
out_unlock:
|
|
xfs_iunlock(ip, lockmode);
|
|
return error;
|
|
}
|
|
|
|
const struct iomap_ops xfs_seek_iomap_ops = {
|
|
.iomap_begin = xfs_seek_iomap_begin,
|
|
};
|
|
|
|
static int
|
|
xfs_xattr_iomap_begin(
|
|
struct inode *inode,
|
|
loff_t offset,
|
|
loff_t length,
|
|
unsigned flags,
|
|
struct iomap *iomap)
|
|
{
|
|
struct xfs_inode *ip = XFS_I(inode);
|
|
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 + length);
|
|
struct xfs_bmbt_irec imap;
|
|
int nimaps = 1, error = 0;
|
|
unsigned lockmode;
|
|
|
|
if (XFS_FORCED_SHUTDOWN(mp))
|
|
return -EIO;
|
|
|
|
lockmode = xfs_ilock_attr_map_shared(ip);
|
|
|
|
/* if there are no attribute fork or extents, return ENOENT */
|
|
if (!XFS_IFORK_Q(ip) || !ip->i_d.di_anextents) {
|
|
error = -ENOENT;
|
|
goto out_unlock;
|
|
}
|
|
|
|
ASSERT(ip->i_d.di_aformat != XFS_DINODE_FMT_LOCAL);
|
|
error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb, &imap,
|
|
&nimaps, XFS_BMAPI_ATTRFORK);
|
|
out_unlock:
|
|
xfs_iunlock(ip, lockmode);
|
|
|
|
if (error)
|
|
return error;
|
|
ASSERT(nimaps);
|
|
return xfs_bmbt_to_iomap(ip, iomap, &imap, false);
|
|
}
|
|
|
|
const struct iomap_ops xfs_xattr_iomap_ops = {
|
|
.iomap_begin = xfs_xattr_iomap_begin,
|
|
};
|