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Diffstat (limited to '')
| -rw-r--r-- | fs/xfs/xfs_iomap.c | 1391 |
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); +} |