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-rw-r--r--fs/xfs/xfs_iomap.c1391
1 files changed, 1391 insertions, 0 deletions
diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
new file mode 100644
index 000000000..07da03976
--- /dev/null
+++ b/fs/xfs/xfs_iomap.c
@@ -0,0 +1,1391 @@
+// 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;
+}
+
+int
+xfs_bmbt_to_iomap(
+ struct xfs_inode *ip,
+ struct iomap *iomap,
+ struct xfs_bmbt_irec *imap,
+ unsigned int mapping_flags,
+ u16 iomap_flags)
+{
+ 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;
+ 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)
+{
+ 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:
+ 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;
+
+ 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;
+ }
+
+ 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);
+
+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);
+ 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);
+
+out_found_cow:
+ xfs_iunlock(ip, lockmode);
+ 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) {
+ error = xfs_bmbt_to_iomap(ip, srcmap, &imap, flags, 0);
+ if (error)
+ return error;
+ }
+ return xfs_bmbt_to_iomap(ip, iomap, &cmap, flags, IOMAP_F_SHARED);
+
+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;
+
+ 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.
+ */
+ 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);
+
+found_imap:
+ xfs_iunlock(ip, XFS_ILOCK_EXCL);
+ return xfs_bmbt_to_iomap(ip, iomap, &imap, flags, 0);
+
+found_cow:
+ xfs_iunlock(ip, XFS_ILOCK_EXCL);
+ if (imap.br_startoff <= offset_fsb) {
+ error = xfs_bmbt_to_iomap(ip, srcmap, &imap, flags, 0);
+ if (error)
+ return error;
+ return xfs_bmbt_to_iomap(ip, iomap, &cmap, flags,
+ IOMAP_F_SHARED);
+ }
+
+ xfs_trim_extent(&cmap, offset_fsb, imap.br_startoff - offset_fsb);
+ return xfs_bmbt_to_iomap(ip, iomap, &cmap, flags, 0);
+
+out_unlock:
+ xfs_iunlock(ip, XFS_ILOCK_EXCL);
+ return error;
+}
+
+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_inode *ip = XFS_I(inode);
+ struct xfs_mount *mp = ip->i_mount;
+ xfs_fileoff_t start_fsb;
+ xfs_fileoff_t end_fsb;
+ int error = 0;
+
+ if (iomap->type != IOMAP_DELALLOC)
+ return 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_is_shutdown(mp)) {
+ xfs_alert(mp, "%s: unable to clean up ino %lld",
+ __func__, ip->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,
+};
+
+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;
+
+ 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);
+ 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);
+}
+
+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;
+
+ 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);
+ error = xfs_bmbt_to_iomap(ip, iomap, &cmap, flags,
+ IOMAP_F_SHARED);
+ /*
+ * 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, flags, 0);
+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;
+
+ 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:
+ xfs_iunlock(ip, lockmode);
+
+ if (error)
+ return error;
+ ASSERT(nimaps);
+ return xfs_bmbt_to_iomap(ip, iomap, &imap, flags, 0);
+}
+
+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);
+}