// 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; } /* If we didn't reserve the blocks, we're not allowed to punch them. */ if (!(iomap->flags & IOMAP_F_NEW)) return 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); /* Nothing to do if we've written the entire delalloc extent */ if (start_fsb >= end_fsb) return 0; /* * Lock the mapping to avoid races with page faults re-instantiating * folios and dirtying them via ->page_mkwrite between the page cache * truncation and the delalloc extent removal. Failing to do this can * leave dirty pages with no space reservation in the cache. */ filemap_invalidate_lock(inode->i_mapping); 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); filemap_invalidate_unlock(inode->i_mapping); 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, }; /* * 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; 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); }