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linux/fs/xfs/xfs_iomap.c
Dave Chinner 6e8af15ccd xfs: drop write error injection is unfixable, remove it 
With the changes to scan the page cache for dirty data to avoid data
corruptions from partial write cleanup racing with other page cache
operations, the drop writes error injection no longer works the same
way it used to and causes xfs/196 to fail. This is because xfs/196
writes to the file and populates the page cache before it turns on
the error injection and starts failing -overwrites-.

The result is that the original drop-writes code failed writes only
-after- overwriting the data in the cache, followed by invalidates
the cached data, then punching out the delalloc extent from under
that data.

On the surface, this looks fine. The problem is that page cache
invalidation *doesn't guarantee that it removes anything from the
page cache* and it doesn't change the dirty state of the folio. When
block size == page size and we do page aligned IO (as xfs/196 does)
everything happens to align perfectly and page cache invalidation
removes the single page folios that span the written data. Hence the
followup delalloc punch pass does not find cached data over that
range and it can punch the extent out.

IOWs, xfs/196 "works" for block size == page size with the new
code. I say "works", because it actually only works for the case
where IO is page aligned, and no data was read from disk before
writes occur. Because the moment we actually read data first, the
readahead code allocates multipage folios and suddenly the
invalidate code goes back to zeroing subfolio ranges without
changing dirty state.

Hence, with multipage folios in play, block size == page size is
functionally identical to block size < page size behaviour, and
drop-writes is manifestly broken w.r.t to this case. Invalidation of
a subfolio range doesn't result in the folio being removed from the
cache, just the range gets zeroed. Hence after we've sequentially
walked over a folio that we've dirtied (via write data) and then
invalidated, we end up with a dirty folio full of zeroed data.

And because the new code skips punching ranges that have dirty
folios covering them, we end up leaving the delalloc range intact
after failing all the writes. Hence failed writes now end up
writing zeroes to disk in the cases where invalidation zeroes folios
rather than removing them from cache.

This is a fundamental change of behaviour that is needed to avoid
the data corruption vectors that exist in the old write fail path,
and it renders the drop-writes injection non-functional and
unworkable as it stands.

As it is, I think the error injection is also now unnecessary, as
partial writes that need delalloc extent are going to be a lot more
common with stale iomap detection in place. Hence this patch removes
the drop-writes error injection completely. xfs/196 can remain for
testing kernels that don't have this data corruption fix, but those
that do will report:

xfs/196 3s ... [not run] XFS error injection drop_writes unknown on this kernel.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
2022-11-29 09:09:17 +11:00

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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2000-2006 Silicon Graphics, Inc.
* Copyright (c) 2016-2018 Christoph Hellwig.
* All Rights Reserved.
*/
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_shared.h"
#include "xfs_format.h"
#include "xfs_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_mount.h"
#include "xfs_inode.h"
#include "xfs_btree.h"
#include "xfs_bmap_btree.h"
#include "xfs_bmap.h"
#include "xfs_bmap_util.h"
#include "xfs_errortag.h"
#include "xfs_error.h"
#include "xfs_trans.h"
#include "xfs_trans_space.h"
#include "xfs_inode_item.h"
#include "xfs_iomap.h"
#include "xfs_trace.h"
#include "xfs_quota.h"
#include "xfs_dquot_item.h"
#include "xfs_dquot.h"
#include "xfs_reflink.h"
#define XFS_ALLOC_ALIGN(mp, off) \
(((off) >> mp->m_allocsize_log) << mp->m_allocsize_log)
static int
xfs_alert_fsblock_zero(
xfs_inode_t *ip,
xfs_bmbt_irec_t *imap)
{
xfs_alert_tag(ip->i_mount, XFS_PTAG_FSBLOCK_ZERO,
"Access to block zero in inode %llu "
"start_block: %llx start_off: %llx "
"blkcnt: %llx extent-state: %x",
(unsigned long long)ip->i_ino,
(unsigned long long)imap->br_startblock,
(unsigned long long)imap->br_startoff,
(unsigned long long)imap->br_blockcount,
imap->br_state);
return -EFSCORRUPTED;
}
u64
xfs_iomap_inode_sequence(
struct xfs_inode *ip,
u16 iomap_flags)
{
u64 cookie = 0;
if (iomap_flags & IOMAP_F_XATTR)
return READ_ONCE(ip->i_af.if_seq);
if ((iomap_flags & IOMAP_F_SHARED) && ip->i_cowfp)
cookie = (u64)READ_ONCE(ip->i_cowfp->if_seq) << 32;
return cookie | READ_ONCE(ip->i_df.if_seq);
}
/*
* Check that the iomap passed to us is still valid for the given offset and
* length.
*/
static bool
xfs_iomap_valid(
struct inode *inode,
const struct iomap *iomap)
{
return iomap->validity_cookie ==
xfs_iomap_inode_sequence(XFS_I(inode), iomap->flags);
}
const struct iomap_page_ops xfs_iomap_page_ops = {
.iomap_valid = xfs_iomap_valid,
};
int
xfs_bmbt_to_iomap(
struct xfs_inode *ip,
struct iomap *iomap,
struct xfs_bmbt_irec *imap,
unsigned int mapping_flags,
u16 iomap_flags,
u64 sequence_cookie)
{
struct xfs_mount *mp = ip->i_mount;
struct xfs_buftarg *target = xfs_inode_buftarg(ip);
if (unlikely(!xfs_valid_startblock(ip, imap->br_startblock)))
return xfs_alert_fsblock_zero(ip, imap);
if (imap->br_startblock == HOLESTARTBLOCK) {
iomap->addr = IOMAP_NULL_ADDR;
iomap->type = IOMAP_HOLE;
} else if (imap->br_startblock == DELAYSTARTBLOCK ||
isnullstartblock(imap->br_startblock)) {
iomap->addr = IOMAP_NULL_ADDR;
iomap->type = IOMAP_DELALLOC;
} else {
iomap->addr = BBTOB(xfs_fsb_to_db(ip, imap->br_startblock));
if (mapping_flags & IOMAP_DAX)
iomap->addr += target->bt_dax_part_off;
if (imap->br_state == XFS_EXT_UNWRITTEN)
iomap->type = IOMAP_UNWRITTEN;
else
iomap->type = IOMAP_MAPPED;
}
iomap->offset = XFS_FSB_TO_B(mp, imap->br_startoff);
iomap->length = XFS_FSB_TO_B(mp, imap->br_blockcount);
if (mapping_flags & IOMAP_DAX)
iomap->dax_dev = target->bt_daxdev;
else
iomap->bdev = target->bt_bdev;
iomap->flags = iomap_flags;
if (xfs_ipincount(ip) &&
(ip->i_itemp->ili_fsync_fields & ~XFS_ILOG_TIMESTAMP))
iomap->flags |= IOMAP_F_DIRTY;
iomap->validity_cookie = sequence_cookie;
iomap->page_ops = &xfs_iomap_page_ops;
return 0;
}
static void
xfs_hole_to_iomap(
struct xfs_inode *ip,
struct iomap *iomap,
xfs_fileoff_t offset_fsb,
xfs_fileoff_t end_fsb)
{
struct xfs_buftarg *target = xfs_inode_buftarg(ip);
iomap->addr = IOMAP_NULL_ADDR;
iomap->type = IOMAP_HOLE;
iomap->offset = XFS_FSB_TO_B(ip->i_mount, offset_fsb);
iomap->length = XFS_FSB_TO_B(ip->i_mount, end_fsb - offset_fsb);
iomap->bdev = target->bt_bdev;
iomap->dax_dev = target->bt_daxdev;
}
static inline xfs_fileoff_t
xfs_iomap_end_fsb(
struct xfs_mount *mp,
loff_t offset,
loff_t count)
{
ASSERT(offset <= mp->m_super->s_maxbytes);
return min(XFS_B_TO_FSB(mp, offset + count),
XFS_B_TO_FSB(mp, mp->m_super->s_maxbytes));
}
static xfs_extlen_t
xfs_eof_alignment(
struct xfs_inode *ip)
{
struct xfs_mount *mp = ip->i_mount;
xfs_extlen_t align = 0;
if (!XFS_IS_REALTIME_INODE(ip)) {
/*
* Round up the allocation request to a stripe unit
* (m_dalign) boundary if the file size is >= stripe unit
* size, and we are allocating past the allocation eof.
*
* If mounted with the "-o swalloc" option the alignment is
* increased from the strip unit size to the stripe width.
*/
if (mp->m_swidth && xfs_has_swalloc(mp))
align = mp->m_swidth;
else if (mp->m_dalign)
align = mp->m_dalign;
if (align && XFS_ISIZE(ip) < XFS_FSB_TO_B(mp, align))
align = 0;
}
return align;
}
/*
* Check if last_fsb is outside the last extent, and if so grow it to the next
* stripe unit boundary.
*/
xfs_fileoff_t
xfs_iomap_eof_align_last_fsb(
struct xfs_inode *ip,
xfs_fileoff_t end_fsb)
{
struct xfs_ifork *ifp = xfs_ifork_ptr(ip, XFS_DATA_FORK);
xfs_extlen_t extsz = xfs_get_extsz_hint(ip);
xfs_extlen_t align = xfs_eof_alignment(ip);
struct xfs_bmbt_irec irec;
struct xfs_iext_cursor icur;
ASSERT(!xfs_need_iread_extents(ifp));
/*
* Always round up the allocation request to the extent hint boundary.
*/
if (extsz) {
if (align)
align = roundup_64(align, extsz);
else
align = extsz;
}
if (align) {
xfs_fileoff_t aligned_end_fsb = roundup_64(end_fsb, align);
xfs_iext_last(ifp, &icur);
if (!xfs_iext_get_extent(ifp, &icur, &irec) ||
aligned_end_fsb >= irec.br_startoff + irec.br_blockcount)
return aligned_end_fsb;
}
return end_fsb;
}
int
xfs_iomap_write_direct(
struct xfs_inode *ip,
xfs_fileoff_t offset_fsb,
xfs_fileoff_t count_fsb,
unsigned int flags,
struct xfs_bmbt_irec *imap,
u64 *seq)
{
struct xfs_mount *mp = ip->i_mount;
struct xfs_trans *tp;
xfs_filblks_t resaligned;
int nimaps;
unsigned int dblocks, rblocks;
bool force = false;
int error;
int bmapi_flags = XFS_BMAPI_PREALLOC;
int nr_exts = XFS_IEXT_ADD_NOSPLIT_CNT;
ASSERT(count_fsb > 0);
resaligned = xfs_aligned_fsb_count(offset_fsb, count_fsb,
xfs_get_extsz_hint(ip));
if (unlikely(XFS_IS_REALTIME_INODE(ip))) {
dblocks = XFS_DIOSTRAT_SPACE_RES(mp, 0);
rblocks = resaligned;
} else {
dblocks = XFS_DIOSTRAT_SPACE_RES(mp, resaligned);
rblocks = 0;
}
error = xfs_qm_dqattach(ip);
if (error)
return error;
/*
* For DAX, we do not allocate unwritten extents, but instead we zero
* the block before we commit the transaction. Ideally we'd like to do
* this outside the transaction context, but if we commit and then crash
* we may not have zeroed the blocks and this will be exposed on
* recovery of the allocation. Hence we must zero before commit.
*
* Further, if we are mapping unwritten extents here, we need to zero
* and convert them to written so that we don't need an unwritten extent
* callback for DAX. This also means that we need to be able to dip into
* the reserve block pool for bmbt block allocation if there is no space
* left but we need to do unwritten extent conversion.
*/
if (flags & IOMAP_DAX) {
bmapi_flags = XFS_BMAPI_CONVERT | XFS_BMAPI_ZERO;
if (imap->br_state == XFS_EXT_UNWRITTEN) {
force = true;
nr_exts = XFS_IEXT_WRITE_UNWRITTEN_CNT;
dblocks = XFS_DIOSTRAT_SPACE_RES(mp, 0) << 1;
}
}
error = xfs_trans_alloc_inode(ip, &M_RES(mp)->tr_write, dblocks,
rblocks, force, &tp);
if (error)
return error;
error = xfs_iext_count_may_overflow(ip, XFS_DATA_FORK, nr_exts);
if (error == -EFBIG)
error = xfs_iext_count_upgrade(tp, ip, nr_exts);
if (error)
goto out_trans_cancel;
/*
* From this point onwards we overwrite the imap pointer that the
* caller gave to us.
*/
nimaps = 1;
error = xfs_bmapi_write(tp, ip, offset_fsb, count_fsb, bmapi_flags, 0,
imap, &nimaps);
if (error)
goto out_trans_cancel;
/*
* Complete the transaction
*/
error = xfs_trans_commit(tp);
if (error)
goto out_unlock;
/*
* Copy any maps to caller's array and return any error.
*/
if (nimaps == 0) {
error = -ENOSPC;
goto out_unlock;
}
if (unlikely(!xfs_valid_startblock(ip, imap->br_startblock)))
error = xfs_alert_fsblock_zero(ip, imap);
out_unlock:
*seq = xfs_iomap_inode_sequence(ip, 0);
xfs_iunlock(ip, XFS_ILOCK_EXCL);
return error;
out_trans_cancel:
xfs_trans_cancel(tp);
goto out_unlock;
}
STATIC bool
xfs_quota_need_throttle(
struct xfs_inode *ip,
xfs_dqtype_t type,
xfs_fsblock_t alloc_blocks)
{
struct xfs_dquot *dq = xfs_inode_dquot(ip, type);
if (!dq || !xfs_this_quota_on(ip->i_mount, type))
return false;
/* no hi watermark, no throttle */
if (!dq->q_prealloc_hi_wmark)
return false;
/* under the lo watermark, no throttle */
if (dq->q_blk.reserved + alloc_blocks < dq->q_prealloc_lo_wmark)
return false;
return true;
}
STATIC void
xfs_quota_calc_throttle(
struct xfs_inode *ip,
xfs_dqtype_t type,
xfs_fsblock_t *qblocks,
int *qshift,
int64_t *qfreesp)
{
struct xfs_dquot *dq = xfs_inode_dquot(ip, type);
int64_t freesp;
int shift = 0;
/* no dq, or over hi wmark, squash the prealloc completely */
if (!dq || dq->q_blk.reserved >= dq->q_prealloc_hi_wmark) {
*qblocks = 0;
*qfreesp = 0;
return;
}
freesp = dq->q_prealloc_hi_wmark - dq->q_blk.reserved;
if (freesp < dq->q_low_space[XFS_QLOWSP_5_PCNT]) {
shift = 2;
if (freesp < dq->q_low_space[XFS_QLOWSP_3_PCNT])
shift += 2;
if (freesp < dq->q_low_space[XFS_QLOWSP_1_PCNT])
shift += 2;
}
if (freesp < *qfreesp)
*qfreesp = freesp;
/* only overwrite the throttle values if we are more aggressive */
if ((freesp >> shift) < (*qblocks >> *qshift)) {
*qblocks = freesp;
*qshift = shift;
}
}
/*
* If we don't have a user specified preallocation size, dynamically increase
* the preallocation size as the size of the file grows. Cap the maximum size
* at a single extent or less if the filesystem is near full. The closer the
* filesystem is to being full, the smaller the maximum preallocation.
*/
STATIC xfs_fsblock_t
xfs_iomap_prealloc_size(
struct xfs_inode *ip,
int whichfork,
loff_t offset,
loff_t count,
struct xfs_iext_cursor *icur)
{
struct xfs_iext_cursor ncur = *icur;
struct xfs_bmbt_irec prev, got;
struct xfs_mount *mp = ip->i_mount;
struct xfs_ifork *ifp = xfs_ifork_ptr(ip, whichfork);
xfs_fileoff_t offset_fsb = XFS_B_TO_FSBT(mp, offset);
int64_t freesp;
xfs_fsblock_t qblocks;
xfs_fsblock_t alloc_blocks = 0;
xfs_extlen_t plen;
int shift = 0;
int qshift = 0;
/*
* As an exception we don't do any preallocation at all if the file is
* smaller than the minimum preallocation and we are using the default
* dynamic preallocation scheme, as it is likely this is the only write
* to the file that is going to be done.
*/
if (XFS_ISIZE(ip) < XFS_FSB_TO_B(mp, mp->m_allocsize_blocks))
return 0;
/*
* Use the minimum preallocation size for small files or if we are
* writing right after a hole.
*/
if (XFS_ISIZE(ip) < XFS_FSB_TO_B(mp, mp->m_dalign) ||
!xfs_iext_prev_extent(ifp, &ncur, &prev) ||
prev.br_startoff + prev.br_blockcount < offset_fsb)
return mp->m_allocsize_blocks;
/*
* Take the size of the preceding data extents as the basis for the
* preallocation size. Note that we don't care if the previous extents
* are written or not.
*/
plen = prev.br_blockcount;
while (xfs_iext_prev_extent(ifp, &ncur, &got)) {
if (plen > XFS_MAX_BMBT_EXTLEN / 2 ||
isnullstartblock(got.br_startblock) ||
got.br_startoff + got.br_blockcount != prev.br_startoff ||
got.br_startblock + got.br_blockcount != prev.br_startblock)
break;
plen += got.br_blockcount;
prev = got;
}
/*
* If the size of the extents is greater than half the maximum extent
* length, then use the current offset as the basis. This ensures that
* for large files the preallocation size always extends to
* XFS_BMBT_MAX_EXTLEN rather than falling short due to things like stripe
* unit/width alignment of real extents.
*/
alloc_blocks = plen * 2;
if (alloc_blocks > XFS_MAX_BMBT_EXTLEN)
alloc_blocks = XFS_B_TO_FSB(mp, offset);
qblocks = alloc_blocks;
/*
* XFS_BMBT_MAX_EXTLEN is not a power of two value but we round the prealloc
* down to the nearest power of two value after throttling. To prevent
* the round down from unconditionally reducing the maximum supported
* prealloc size, we round up first, apply appropriate throttling, round
* down and cap the value to XFS_BMBT_MAX_EXTLEN.
*/
alloc_blocks = XFS_FILEOFF_MIN(roundup_pow_of_two(XFS_MAX_BMBT_EXTLEN),
alloc_blocks);
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_DQTYPE_USER, alloc_blocks))
xfs_quota_calc_throttle(ip, XFS_DQTYPE_USER, &qblocks, &qshift,
&freesp);
if (xfs_quota_need_throttle(ip, XFS_DQTYPE_GROUP, alloc_blocks))
xfs_quota_calc_throttle(ip, XFS_DQTYPE_GROUP, &qblocks, &qshift,
&freesp);
if (xfs_quota_need_throttle(ip, XFS_DQTYPE_PROJ, alloc_blocks))
xfs_quota_calc_throttle(ip, XFS_DQTYPE_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 > XFS_MAX_BMBT_EXTLEN)
alloc_blocks = XFS_MAX_BMBT_EXTLEN;
/*
* 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 XFS_BMBT_MAX_EXTLEN.
*/
while (alloc_blocks && alloc_blocks >= freesp)
alloc_blocks >>= 4;
if (alloc_blocks < mp->m_allocsize_blocks)
alloc_blocks = mp->m_allocsize_blocks;
trace_xfs_iomap_prealloc_size(ip, alloc_blocks, shift,
mp->m_allocsize_blocks);
return alloc_blocks;
}
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;
/* Attach dquots so that bmbt splits are accounted correctly. */
error = xfs_qm_dqattach(ip);
if (error)
return error;
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_inode(ip, &M_RES(mp)->tr_write, resblks,
0, true, &tp);
if (error)
return error;
error = xfs_iext_count_may_overflow(ip, XFS_DATA_FORK,
XFS_IEXT_WRITE_UNWRITTEN_CNT);
if (error == -EFBIG)
error = xfs_iext_count_upgrade(tp, ip,
XFS_IEXT_WRITE_UNWRITTEN_CNT);
if (error)
goto error_on_bmapi_transaction;
/*
* 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_disk_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 (unlikely(!xfs_valid_startblock(ip, imap.br_startblock)))
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,
unsigned flags,
struct xfs_bmbt_irec *imap,
int nimaps)
{
/* don't allocate blocks when just zeroing */
if (flags & IOMAP_ZERO)
return false;
if (!nimaps ||
imap->br_startblock == HOLESTARTBLOCK ||
imap->br_startblock == DELAYSTARTBLOCK)
return true;
/* we convert unwritten extents before copying the data for DAX */
if ((flags & IOMAP_DAX) && imap->br_state == XFS_EXT_UNWRITTEN)
return true;
return false;
}
static inline bool
imap_needs_cow(
struct xfs_inode *ip,
unsigned int flags,
struct xfs_bmbt_irec *imap,
int nimaps)
{
if (!xfs_is_cow_inode(ip))
return false;
/* when zeroing we don't have to COW holes or unwritten extents */
if (flags & IOMAP_ZERO) {
if (!nimaps ||
imap->br_startblock == HOLESTARTBLOCK ||
imap->br_state == XFS_EXT_UNWRITTEN)
return false;
}
return true;
}
static int
xfs_ilock_for_iomap(
struct xfs_inode *ip,
unsigned flags,
unsigned *lockmode)
{
unsigned int mode = *lockmode;
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)
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 (xfs_need_iread_extents(&ip->i_df)) {
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;
}
/*
* Check that the imap we are going to return to the caller spans the entire
* range that the caller requested for the IO.
*/
static bool
imap_spans_range(
struct xfs_bmbt_irec *imap,
xfs_fileoff_t offset_fsb,
xfs_fileoff_t end_fsb)
{
if (imap->br_startoff > offset_fsb)
return false;
if (imap->br_startoff + imap->br_blockcount < end_fsb)
return false;
return true;
}
static int
xfs_direct_write_iomap_begin(
struct inode *inode,
loff_t offset,
loff_t length,
unsigned flags,
struct iomap *iomap,
struct iomap *srcmap)
{
struct xfs_inode *ip = XFS_I(inode);
struct xfs_mount *mp = ip->i_mount;
struct xfs_bmbt_irec imap, cmap;
xfs_fileoff_t offset_fsb = XFS_B_TO_FSBT(mp, offset);
xfs_fileoff_t end_fsb = xfs_iomap_end_fsb(mp, offset, length);
int nimaps = 1, error = 0;
bool shared = false;
u16 iomap_flags = 0;
unsigned int lockmode = XFS_ILOCK_SHARED;
u64 seq;
ASSERT(flags & (IOMAP_WRITE | IOMAP_ZERO));
if (xfs_is_shutdown(mp))
return -EIO;
/*
* Writes that span EOF might trigger an IO size update on completion,
* so consider them to be dirty for the purposes of O_DSYNC even if
* there is no other metadata changes pending or have been made here.
*/
if (offset + length > i_size_read(inode))
iomap_flags |= IOMAP_F_DIRTY;
error = xfs_ilock_for_iomap(ip, flags, &lockmode);
if (error)
return error;
error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb, &imap,
&nimaps, 0);
if (error)
goto out_unlock;
if (imap_needs_cow(ip, flags, &imap, nimaps)) {
error = -EAGAIN;
if (flags & IOMAP_NOWAIT)
goto out_unlock;
/* may drop and re-acquire the ilock */
error = xfs_reflink_allocate_cow(ip, &imap, &cmap, &shared,
&lockmode,
(flags & IOMAP_DIRECT) || IS_DAX(inode));
if (error)
goto out_unlock;
if (shared)
goto out_found_cow;
end_fsb = imap.br_startoff + imap.br_blockcount;
length = XFS_FSB_TO_B(mp, end_fsb) - offset;
}
if (imap_needs_alloc(inode, flags, &imap, nimaps))
goto allocate_blocks;
/*
* NOWAIT and OVERWRITE I/O needs to span the entire requested I/O with
* a single map so that we avoid partial IO failures due to the rest of
* the I/O range not covered by this map triggering an EAGAIN condition
* when it is subsequently mapped and aborting the I/O.
*/
if (flags & (IOMAP_NOWAIT | IOMAP_OVERWRITE_ONLY)) {
error = -EAGAIN;
if (!imap_spans_range(&imap, offset_fsb, end_fsb))
goto out_unlock;
}
/*
* For overwrite only I/O, we cannot convert unwritten extents without
* requiring sub-block zeroing. This can only be done under an
* exclusive IOLOCK, hence return -EAGAIN if this is not a written
* extent to tell the caller to try again.
*/
if (flags & IOMAP_OVERWRITE_ONLY) {
error = -EAGAIN;
if (imap.br_state != XFS_EXT_NORM &&
((offset | length) & mp->m_blockmask))
goto out_unlock;
}
seq = xfs_iomap_inode_sequence(ip, iomap_flags);
xfs_iunlock(ip, lockmode);
trace_xfs_iomap_found(ip, offset, length, XFS_DATA_FORK, &imap);
return xfs_bmbt_to_iomap(ip, iomap, &imap, flags, iomap_flags, seq);
allocate_blocks:
error = -EAGAIN;
if (flags & (IOMAP_NOWAIT | IOMAP_OVERWRITE_ONLY))
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);
end_fsb = xfs_iomap_end_fsb(mp, offset, length);
if (offset + length > XFS_ISIZE(ip))
end_fsb = xfs_iomap_eof_align_last_fsb(ip, end_fsb);
else if (nimaps && imap.br_startblock == HOLESTARTBLOCK)
end_fsb = min(end_fsb, imap.br_startoff + imap.br_blockcount);
xfs_iunlock(ip, lockmode);
error = xfs_iomap_write_direct(ip, offset_fsb, end_fsb - offset_fsb,
flags, &imap, &seq);
if (error)
return error;
trace_xfs_iomap_alloc(ip, offset, length, XFS_DATA_FORK, &imap);
return xfs_bmbt_to_iomap(ip, iomap, &imap, flags,
iomap_flags | IOMAP_F_NEW, seq);
out_found_cow:
length = XFS_FSB_TO_B(mp, cmap.br_startoff + cmap.br_blockcount);
trace_xfs_iomap_found(ip, offset, length - offset, XFS_COW_FORK, &cmap);
if (imap.br_startblock != HOLESTARTBLOCK) {
seq = xfs_iomap_inode_sequence(ip, 0);
error = xfs_bmbt_to_iomap(ip, srcmap, &imap, flags, 0, seq);
if (error)
goto out_unlock;
}
seq = xfs_iomap_inode_sequence(ip, IOMAP_F_SHARED);
xfs_iunlock(ip, lockmode);
return xfs_bmbt_to_iomap(ip, iomap, &cmap, flags, IOMAP_F_SHARED, seq);
out_unlock:
if (lockmode)
xfs_iunlock(ip, lockmode);
return error;
}
const struct iomap_ops xfs_direct_write_iomap_ops = {
.iomap_begin = xfs_direct_write_iomap_begin,
};
static int
xfs_dax_write_iomap_end(
struct inode *inode,
loff_t pos,
loff_t length,
ssize_t written,
unsigned flags,
struct iomap *iomap)
{
struct xfs_inode *ip = XFS_I(inode);
if (!xfs_is_cow_inode(ip))
return 0;
if (!written) {
xfs_reflink_cancel_cow_range(ip, pos, length, true);
return 0;
}
return xfs_reflink_end_cow(ip, pos, written);
}
const struct iomap_ops xfs_dax_write_iomap_ops = {
.iomap_begin = xfs_direct_write_iomap_begin,
.iomap_end = xfs_dax_write_iomap_end,
};
static int
xfs_buffered_write_iomap_begin(
struct inode *inode,
loff_t offset,
loff_t count,
unsigned flags,
struct iomap *iomap,
struct iomap *srcmap)
{
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_iomap_end_fsb(mp, offset, count);
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 allocfork = XFS_DATA_FORK;
int error = 0;
unsigned int lockmode = XFS_ILOCK_EXCL;
u64 seq;
if (xfs_is_shutdown(mp))
return -EIO;
/* we can't use delayed allocations when using extent size hints */
if (xfs_get_extsz_hint(ip))
return xfs_direct_write_iomap_begin(inode, offset, count,
flags, iomap, srcmap);
ASSERT(!XFS_IS_REALTIME_INODE(ip));
error = xfs_ilock_for_iomap(ip, flags, &lockmode);
if (error)
return error;
if (XFS_IS_CORRUPT(mp, !xfs_ifork_has_extents(&ip->i_df)) ||
XFS_TEST_ERROR(false, mp, XFS_ERRTAG_BMAPIFORMAT)) {
error = -EFSCORRUPTED;
goto out_unlock;
}
XFS_STATS_INC(mp, xs_blk_mapw);
error = xfs_iread_extents(NULL, ip, XFS_DATA_FORK);
if (error)
goto out_unlock;
/*
* Search the data 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);
goto found_cow;
}
}
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 found_imap;
}
xfs_trim_extent(&imap, offset_fsb, end_fsb - offset_fsb);
/* Trim the mapping to the nearest shared extent boundary. */
error = xfs_bmap_trim_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 found_imap;
}
/*
* Fork all the shared blocks from our write offset until the
* end of the extent.
*/
allocfork = 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 = xfs_iomap_end_fsb(mp, offset, count);
if (xfs_is_always_cow_inode(ip))
allocfork = XFS_COW_FORK;
}
error = xfs_qm_dqattach_locked(ip, false);
if (error)
goto out_unlock;
if (eof && offset + count > XFS_ISIZE(ip)) {
/*
* Determine the initial size of the preallocation.
* We clean up any extra preallocation when the file is closed.
*/
if (xfs_has_allocsize(mp))
prealloc_blocks = mp->m_allocsize_blocks;
else
prealloc_blocks = xfs_iomap_prealloc_size(ip, allocfork,
offset, count, &icur);
if (prealloc_blocks) {
xfs_extlen_t align;
xfs_off_t end_offset;
xfs_fileoff_t p_end_fsb;
end_offset = XFS_ALLOC_ALIGN(mp, offset + count - 1);
p_end_fsb = XFS_B_TO_FSBT(mp, end_offset) +
prealloc_blocks;
align = xfs_eof_alignment(ip);
if (align)
p_end_fsb = roundup_64(p_end_fsb, align);
p_end_fsb = min(p_end_fsb,
XFS_B_TO_FSB(mp, mp->m_super->s_maxbytes));
ASSERT(p_end_fsb > offset_fsb);
prealloc_blocks = p_end_fsb - end_fsb;
}
}
retry:
error = xfs_bmapi_reserve_delalloc(ip, allocfork, offset_fsb,
end_fsb - offset_fsb, prealloc_blocks,
allocfork == XFS_DATA_FORK ? &imap : &cmap,
allocfork == XFS_DATA_FORK ? &icur : &ccur,
allocfork == 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;
}
fallthrough;
default:
goto out_unlock;
}
if (allocfork == XFS_COW_FORK) {
trace_xfs_iomap_alloc(ip, offset, count, allocfork, &cmap);
goto found_cow;
}
/*
* Flag newly allocated delalloc blocks with IOMAP_F_NEW so we punch
* them out if the write happens to fail.
*/
seq = xfs_iomap_inode_sequence(ip, IOMAP_F_NEW);
xfs_iunlock(ip, XFS_ILOCK_EXCL);
trace_xfs_iomap_alloc(ip, offset, count, allocfork, &imap);
return xfs_bmbt_to_iomap(ip, iomap, &imap, flags, IOMAP_F_NEW, seq);
found_imap:
seq = xfs_iomap_inode_sequence(ip, 0);
xfs_iunlock(ip, XFS_ILOCK_EXCL);
return xfs_bmbt_to_iomap(ip, iomap, &imap, flags, 0, seq);
found_cow:
seq = xfs_iomap_inode_sequence(ip, 0);
if (imap.br_startoff <= offset_fsb) {
error = xfs_bmbt_to_iomap(ip, srcmap, &imap, flags, 0, seq);
if (error)
goto out_unlock;
seq = xfs_iomap_inode_sequence(ip, IOMAP_F_SHARED);
xfs_iunlock(ip, XFS_ILOCK_EXCL);
return xfs_bmbt_to_iomap(ip, iomap, &cmap, flags,
IOMAP_F_SHARED, seq);
}
xfs_trim_extent(&cmap, offset_fsb, imap.br_startoff - offset_fsb);
xfs_iunlock(ip, XFS_ILOCK_EXCL);
return xfs_bmbt_to_iomap(ip, iomap, &cmap, flags, 0, seq);
out_unlock:
xfs_iunlock(ip, XFS_ILOCK_EXCL);
return error;
}
static int
xfs_buffered_write_delalloc_punch(
struct inode *inode,
loff_t offset,
loff_t length)
{
return xfs_bmap_punch_delalloc_range(XFS_I(inode), offset,
offset + length);
}
static int
xfs_buffered_write_iomap_end(
struct inode *inode,
loff_t offset,
loff_t length,
ssize_t written,
unsigned flags,
struct iomap *iomap)
{
struct xfs_mount *mp = XFS_M(inode->i_sb);
int error;
error = iomap_file_buffered_write_punch_delalloc(inode, iomap, offset,
length, written, &xfs_buffered_write_delalloc_punch);
if (error && !xfs_is_shutdown(mp)) {
xfs_alert(mp, "%s: unable to clean up ino 0x%llx",
__func__, XFS_I(inode)->i_ino);
return error;
}
return 0;
}
const struct iomap_ops xfs_buffered_write_iomap_ops = {
.iomap_begin = xfs_buffered_write_iomap_begin,
.iomap_end = xfs_buffered_write_iomap_end,
};
/*
* iomap_page_mkwrite() will never fail in a way that requires delalloc extents
* that it allocated to be revoked. Hence we do not need an .iomap_end method
* for this operation.
*/
const struct iomap_ops xfs_page_mkwrite_iomap_ops = {
.iomap_begin = xfs_buffered_write_iomap_begin,
};
static int
xfs_read_iomap_begin(
struct inode *inode,
loff_t offset,
loff_t length,
unsigned flags,
struct iomap *iomap,
struct iomap *srcmap)
{
struct xfs_inode *ip = XFS_I(inode);
struct xfs_mount *mp = ip->i_mount;
struct xfs_bmbt_irec imap;
xfs_fileoff_t offset_fsb = XFS_B_TO_FSBT(mp, offset);
xfs_fileoff_t end_fsb = xfs_iomap_end_fsb(mp, offset, length);
int nimaps = 1, error = 0;
bool shared = false;
unsigned int lockmode = XFS_ILOCK_SHARED;
u64 seq;
ASSERT(!(flags & (IOMAP_WRITE | IOMAP_ZERO)));
if (xfs_is_shutdown(mp))
return -EIO;
error = xfs_ilock_for_iomap(ip, flags, &lockmode);
if (error)
return error;
error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb, &imap,
&nimaps, 0);
if (!error && (flags & IOMAP_REPORT))
error = xfs_reflink_trim_around_shared(ip, &imap, &shared);
seq = xfs_iomap_inode_sequence(ip, shared ? IOMAP_F_SHARED : 0);
xfs_iunlock(ip, lockmode);
if (error)
return error;
trace_xfs_iomap_found(ip, offset, length, XFS_DATA_FORK, &imap);
return xfs_bmbt_to_iomap(ip, iomap, &imap, flags,
shared ? IOMAP_F_SHARED : 0, seq);
}
const struct iomap_ops xfs_read_iomap_ops = {
.iomap_begin = xfs_read_iomap_begin,
};
static int
xfs_seek_iomap_begin(
struct inode *inode,
loff_t offset,
loff_t length,
unsigned flags,
struct iomap *iomap,
struct iomap *srcmap)
{
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;
u64 seq;
if (xfs_is_shutdown(mp))
return -EIO;
lockmode = xfs_ilock_data_map_shared(ip);
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 = xfs_iomap_end_fsb(mp, offset, length);
}
/*
* 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);
seq = xfs_iomap_inode_sequence(ip, IOMAP_F_SHARED);
error = xfs_bmbt_to_iomap(ip, iomap, &cmap, flags,
IOMAP_F_SHARED, seq);
/*
* 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:
seq = xfs_iomap_inode_sequence(ip, 0);
xfs_trim_extent(&imap, offset_fsb, end_fsb);
error = xfs_bmbt_to_iomap(ip, iomap, &imap, flags, 0, seq);
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 iomap *srcmap)
{
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;
int seq;
if (xfs_is_shutdown(mp))
return -EIO;
lockmode = xfs_ilock_attr_map_shared(ip);
/* if there are no attribute fork or extents, return ENOENT */
if (!xfs_inode_has_attr_fork(ip) || !ip->i_af.if_nextents) {
error = -ENOENT;
goto out_unlock;
}
ASSERT(ip->i_af.if_format != XFS_DINODE_FMT_LOCAL);
error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb, &imap,
&nimaps, XFS_BMAPI_ATTRFORK);
out_unlock:
seq = xfs_iomap_inode_sequence(ip, IOMAP_F_XATTR);
xfs_iunlock(ip, lockmode);
if (error)
return error;
ASSERT(nimaps);
return xfs_bmbt_to_iomap(ip, iomap, &imap, flags, IOMAP_F_XATTR, seq);
}
const struct iomap_ops xfs_xattr_iomap_ops = {
.iomap_begin = xfs_xattr_iomap_begin,
};
int
xfs_zero_range(
struct xfs_inode *ip,
loff_t pos,
loff_t len,
bool *did_zero)
{
struct inode *inode = VFS_I(ip);
if (IS_DAX(inode))
return dax_zero_range(inode, pos, len, did_zero,
&xfs_direct_write_iomap_ops);
return iomap_zero_range(inode, pos, len, did_zero,
&xfs_buffered_write_iomap_ops);
}
int
xfs_truncate_page(
struct xfs_inode *ip,
loff_t pos,
bool *did_zero)
{
struct inode *inode = VFS_I(ip);
if (IS_DAX(inode))
return dax_truncate_page(inode, pos, did_zero,
&xfs_direct_write_iomap_ops);
return iomap_truncate_page(inode, pos, did_zero,
&xfs_buffered_write_iomap_ops);
}
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