diff options
Diffstat (limited to 'fs/xfs/xfs_iomap.c')
| -rw-r--r-- | fs/xfs/xfs_iomap.c | 1257 |
1 files changed, 1257 insertions, 0 deletions
diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c new file mode 100644 index 000000000..6320aca39 --- /dev/null +++ b/fs/xfs/xfs_iomap.c @@ -0,0 +1,1257 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (c) 2000-2006 Silicon Graphics, Inc. + * Copyright (c) 2016-2018 Christoph Hellwig. + * All Rights Reserved. + */ +#include <linux/iomap.h> +#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_defer.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_icache.h" +#include "xfs_quota.h" +#include "xfs_dquot_item.h" +#include "xfs_dquot.h" +#include "xfs_reflink.h" + + +#define XFS_WRITEIO_ALIGN(mp,off) (((off) >> mp->m_writeio_log) \ + << mp->m_writeio_log) + +void +xfs_bmbt_to_iomap( + struct xfs_inode *ip, + struct iomap *iomap, + struct xfs_bmbt_irec *imap) +{ + struct xfs_mount *mp = ip->i_mount; + + if (imap->br_startblock == HOLESTARTBLOCK) { + iomap->addr = IOMAP_NULL_ADDR; + iomap->type = IOMAP_HOLE; + } else if (imap->br_startblock == DELAYSTARTBLOCK) { + iomap->addr = IOMAP_NULL_ADDR; + iomap->type = IOMAP_DELALLOC; + } else { + iomap->addr = BBTOB(xfs_fsb_to_db(ip, imap->br_startblock)); + 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); + iomap->bdev = xfs_find_bdev_for_inode(VFS_I(ip)); + iomap->dax_dev = xfs_find_daxdev_for_inode(VFS_I(ip)); +} + +xfs_extlen_t +xfs_eof_alignment( + struct xfs_inode *ip, + xfs_extlen_t extsize) +{ + 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 && (mp->m_flags & XFS_MOUNT_SWALLOC)) + 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; + } + + /* + * Always round up the allocation request to an extent boundary + * (when file on a real-time subvolume or has di_extsize hint). + */ + if (extsize) { + if (align) + align = roundup_64(align, extsize); + else + align = extsize; + } + + return align; +} + +STATIC int +xfs_iomap_eof_align_last_fsb( + struct xfs_inode *ip, + xfs_extlen_t extsize, + xfs_fileoff_t *last_fsb) +{ + xfs_extlen_t align = xfs_eof_alignment(ip, extsize); + + if (align) { + xfs_fileoff_t new_last_fsb = roundup_64(*last_fsb, align); + int eof, error; + + error = xfs_bmap_eof(ip, new_last_fsb, XFS_DATA_FORK, &eof); + if (error) + return error; + if (eof) + *last_fsb = new_last_fsb; + } + return 0; +} + +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_iomap_write_direct( + xfs_inode_t *ip, + xfs_off_t offset, + size_t count, + xfs_bmbt_irec_t *imap, + int nmaps) +{ + xfs_mount_t *mp = ip->i_mount; + xfs_fileoff_t offset_fsb; + xfs_fileoff_t last_fsb; + xfs_filblks_t count_fsb, resaligned; + xfs_extlen_t extsz; + int nimaps; + int quota_flag; + int rt; + xfs_trans_t *tp; + uint qblocks, resblks, resrtextents; + int error; + int lockmode; + int bmapi_flags = XFS_BMAPI_PREALLOC; + uint tflags = 0; + + rt = XFS_IS_REALTIME_INODE(ip); + extsz = xfs_get_extsz_hint(ip); + lockmode = XFS_ILOCK_SHARED; /* locked by caller */ + + ASSERT(xfs_isilocked(ip, lockmode)); + + offset_fsb = XFS_B_TO_FSBT(mp, offset); + last_fsb = XFS_B_TO_FSB(mp, ((xfs_ufsize_t)(offset + count))); + if ((offset + count) > XFS_ISIZE(ip)) { + /* + * Assert that the in-core extent list is present since this can + * call xfs_iread_extents() and we only have the ilock shared. + * This should be safe because the lock was held around a bmapi + * call in the caller and we only need it to access the in-core + * list. + */ + ASSERT(XFS_IFORK_PTR(ip, XFS_DATA_FORK)->if_flags & + XFS_IFEXTENTS); + error = xfs_iomap_eof_align_last_fsb(ip, extsz, &last_fsb); + if (error) + goto out_unlock; + } else { + if (nmaps && (imap->br_startblock == HOLESTARTBLOCK)) + last_fsb = min(last_fsb, (xfs_fileoff_t) + imap->br_blockcount + + imap->br_startoff); + } + count_fsb = last_fsb - offset_fsb; + ASSERT(count_fsb > 0); + resaligned = xfs_aligned_fsb_count(offset_fsb, count_fsb, extsz); + + if (unlikely(rt)) { + resrtextents = qblocks = resaligned; + resrtextents /= mp->m_sb.sb_rextsize; + resblks = XFS_DIOSTRAT_SPACE_RES(mp, 0); + quota_flag = XFS_QMOPT_RES_RTBLKS; + } else { + resrtextents = 0; + resblks = qblocks = XFS_DIOSTRAT_SPACE_RES(mp, resaligned); + quota_flag = XFS_QMOPT_RES_REGBLKS; + } + + /* + * Drop the shared lock acquired by the caller, attach the dquot if + * necessary and move on to transaction setup. + */ + xfs_iunlock(ip, lockmode); + 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 (IS_DAX(VFS_I(ip))) { + bmapi_flags = XFS_BMAPI_CONVERT | XFS_BMAPI_ZERO; + if (imap->br_state == XFS_EXT_UNWRITTEN) { + tflags |= XFS_TRANS_RESERVE; + resblks = XFS_DIOSTRAT_SPACE_RES(mp, 0) << 1; + } + } + error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, resblks, resrtextents, + tflags, &tp); + if (error) + return error; + + lockmode = XFS_ILOCK_EXCL; + xfs_ilock(ip, lockmode); + + error = xfs_trans_reserve_quota_nblks(tp, ip, qblocks, 0, quota_flag); + if (error) + goto out_trans_cancel; + + xfs_trans_ijoin(tp, ip, 0); + + /* + * 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, resblks, imap, &nimaps); + if (error) + goto out_res_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 (!(imap->br_startblock || XFS_IS_REALTIME_INODE(ip))) + error = xfs_alert_fsblock_zero(ip, imap); + +out_unlock: + xfs_iunlock(ip, lockmode); + return error; + +out_res_cancel: + xfs_trans_unreserve_quota_nblks(tp, ip, (long)qblocks, 0, quota_flag); +out_trans_cancel: + xfs_trans_cancel(tp); + goto out_unlock; +} + +STATIC bool +xfs_quota_need_throttle( + struct xfs_inode *ip, + int 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_res_bcount + alloc_blocks < dq->q_prealloc_lo_wmark) + return false; + + return true; +} + +STATIC void +xfs_quota_calc_throttle( + struct xfs_inode *ip, + int type, + xfs_fsblock_t *qblocks, + int *qshift, + int64_t *qfreesp) +{ + int64_t freesp; + int shift = 0; + struct xfs_dquot *dq = xfs_inode_dquot(ip, type); + + /* no dq, or over hi wmark, squash the prealloc completely */ + if (!dq || dq->q_res_bcount >= dq->q_prealloc_hi_wmark) { + *qblocks = 0; + *qfreesp = 0; + return; + } + + freesp = dq->q_prealloc_hi_wmark - dq->q_res_bcount; + 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 are doing a write at the end of the file and there are no allocations + * past this one, then extend the allocation out to the file system's write + * iosize. + * + * 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 full, the smaller the maximum prealocation. + * + * 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. + * + * We clean up any extra space left over when the file is closed in + * xfs_inactive(). + */ +STATIC xfs_fsblock_t +xfs_iomap_prealloc_size( + struct xfs_inode *ip, + loff_t offset, + loff_t count, + struct xfs_iext_cursor *icur) +{ + struct xfs_mount *mp = ip->i_mount; + struct xfs_ifork *ifp = XFS_IFORK_PTR(ip, XFS_DATA_FORK); + xfs_fileoff_t offset_fsb = XFS_B_TO_FSBT(mp, offset); + struct xfs_bmbt_irec prev; + int shift = 0; + int64_t freesp; + xfs_fsblock_t qblocks; + int qshift = 0; + xfs_fsblock_t alloc_blocks = 0; + + if (offset + count <= XFS_ISIZE(ip)) + return 0; + + if (!(mp->m_flags & XFS_MOUNT_DFLT_IOSIZE) && + (XFS_ISIZE(ip) < XFS_FSB_TO_B(mp, mp->m_writeio_blocks))) + return 0; + + /* + * If an explicit allocsize is set, the file is small, or we + * are writing behind a hole, then use the minimum prealloc: + */ + if ((mp->m_flags & XFS_MOUNT_DFLT_IOSIZE) || + XFS_ISIZE(ip) < XFS_FSB_TO_B(mp, mp->m_dalign) || + !xfs_iext_peek_prev_extent(ifp, icur, &prev) || + prev.br_startoff + prev.br_blockcount < offset_fsb) + return mp->m_writeio_blocks; + + /* + * Determine the initial size of the preallocation. We are beyond the + * current EOF here, but we need to take into account whether this is + * a sparse write or an extending write when determining the + * preallocation size. Hence we need to look up the extent that ends + * at the current write offset and use the result to determine the + * preallocation size. + * + * If the extent is a hole, then preallocation is essentially disabled. + * Otherwise we take the size of the preceding data extent as the basis + * for the preallocation size. If the size of the extent 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 MAXEXTLEN rather than falling short due to things + * like stripe unit/width alignment of real extents. + */ + if (prev.br_blockcount <= (MAXEXTLEN >> 1)) + alloc_blocks = prev.br_blockcount << 1; + else + alloc_blocks = XFS_B_TO_FSB(mp, offset); + if (!alloc_blocks) + goto check_writeio; + qblocks = alloc_blocks; + + /* + * MAXEXTLEN 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 MAXEXTLEN. + */ + alloc_blocks = XFS_FILEOFF_MIN(roundup_pow_of_two(MAXEXTLEN), + 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_DQ_USER, alloc_blocks)) + xfs_quota_calc_throttle(ip, XFS_DQ_USER, &qblocks, &qshift, + &freesp); + if (xfs_quota_need_throttle(ip, XFS_DQ_GROUP, alloc_blocks)) + xfs_quota_calc_throttle(ip, XFS_DQ_GROUP, &qblocks, &qshift, + &freesp); + if (xfs_quota_need_throttle(ip, XFS_DQ_PROJ, alloc_blocks)) + xfs_quota_calc_throttle(ip, XFS_DQ_PROJ, &qblocks, &qshift, + &freesp); + + /* + * The final prealloc size is set to the minimum of free space available + * in each of the quotas and the overall filesystem. + * + * The shift throttle value is set to the maximum value as determined by + * the global low free space values and per-quota low free space values. + */ + alloc_blocks = min(alloc_blocks, qblocks); + shift = max(shift, qshift); + + if (shift) + alloc_blocks >>= shift; + /* + * rounddown_pow_of_two() returns an undefined result if we pass in + * alloc_blocks = 0. + */ + if (alloc_blocks) + alloc_blocks = rounddown_pow_of_two(alloc_blocks); + if (alloc_blocks > MAXEXTLEN) + alloc_blocks = MAXEXTLEN; + + /* + * If we are still trying to allocate more space than is + * available, squash the prealloc hard. This can happen if we + * have a large file on a small filesystem and the above + * lowspace thresholds are smaller than MAXEXTLEN. + */ + while (alloc_blocks && alloc_blocks >= freesp) + alloc_blocks >>= 4; +check_writeio: + if (alloc_blocks < mp->m_writeio_blocks) + alloc_blocks = mp->m_writeio_blocks; + trace_xfs_iomap_prealloc_size(ip, alloc_blocks, shift, + mp->m_writeio_blocks); + return alloc_blocks; +} + +static int +xfs_file_iomap_begin_delay( + struct inode *inode, + loff_t offset, + loff_t count, + struct iomap *iomap) +{ + struct xfs_inode *ip = XFS_I(inode); + struct xfs_mount *mp = ip->i_mount; + struct xfs_ifork *ifp = XFS_IFORK_PTR(ip, XFS_DATA_FORK); + xfs_fileoff_t offset_fsb = XFS_B_TO_FSBT(mp, offset); + xfs_fileoff_t maxbytes_fsb = + XFS_B_TO_FSB(mp, mp->m_super->s_maxbytes); + xfs_fileoff_t end_fsb; + int error = 0, eof = 0; + struct xfs_bmbt_irec got; + struct xfs_iext_cursor icur; + xfs_fsblock_t prealloc_blocks = 0; + + ASSERT(!XFS_IS_REALTIME_INODE(ip)); + ASSERT(!xfs_get_extsz_hint(ip)); + + xfs_ilock(ip, XFS_ILOCK_EXCL); + + if (unlikely(XFS_TEST_ERROR( + (XFS_IFORK_FORMAT(ip, XFS_DATA_FORK) != XFS_DINODE_FMT_EXTENTS && + XFS_IFORK_FORMAT(ip, XFS_DATA_FORK) != XFS_DINODE_FMT_BTREE), + mp, XFS_ERRTAG_BMAPIFORMAT))) { + XFS_ERROR_REPORT(__func__, XFS_ERRLEVEL_LOW, mp); + error = -EFSCORRUPTED; + goto out_unlock; + } + + XFS_STATS_INC(mp, xs_blk_mapw); + + if (!(ifp->if_flags & XFS_IFEXTENTS)) { + error = xfs_iread_extents(NULL, ip, XFS_DATA_FORK); + if (error) + goto out_unlock; + } + + eof = !xfs_iext_lookup_extent(ip, ifp, offset_fsb, &icur, &got); + if (!eof && got.br_startoff <= offset_fsb) { + if (xfs_is_reflink_inode(ip)) { + bool shared; + + end_fsb = min(XFS_B_TO_FSB(mp, offset + count), + maxbytes_fsb); + xfs_trim_extent(&got, offset_fsb, end_fsb - offset_fsb); + error = xfs_reflink_reserve_cow(ip, &got, &shared); + if (error) + goto out_unlock; + } + + trace_xfs_iomap_found(ip, offset, count, 0, &got); + goto done; + } + + error = xfs_qm_dqattach_locked(ip, false); + if (error) + goto out_unlock; + + /* + * 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 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. + */ + count = min_t(loff_t, count, 1024 * PAGE_SIZE); + end_fsb = min(XFS_B_TO_FSB(mp, offset + count), maxbytes_fsb); + + if (eof) { + prealloc_blocks = xfs_iomap_prealloc_size(ip, offset, count, + &icur); + if (prealloc_blocks) { + xfs_extlen_t align; + xfs_off_t end_offset; + xfs_fileoff_t p_end_fsb; + + end_offset = XFS_WRITEIO_ALIGN(mp, offset + count - 1); + p_end_fsb = XFS_B_TO_FSBT(mp, end_offset) + + prealloc_blocks; + + align = xfs_eof_alignment(ip, 0); + if (align) + p_end_fsb = roundup_64(p_end_fsb, align); + + p_end_fsb = min(p_end_fsb, maxbytes_fsb); + ASSERT(p_end_fsb > offset_fsb); + prealloc_blocks = p_end_fsb - end_fsb; + } + } + +retry: + error = xfs_bmapi_reserve_delalloc(ip, XFS_DATA_FORK, offset_fsb, + end_fsb - offset_fsb, prealloc_blocks, &got, &icur, + eof); + switch (error) { + case 0: + break; + case -ENOSPC: + case -EDQUOT: + /* retry without any preallocation */ + trace_xfs_delalloc_enospc(ip, offset, count); + if (prealloc_blocks) { + prealloc_blocks = 0; + goto retry; + } + /*FALLTHRU*/ + default: + goto out_unlock; + } + + /* + * Flag newly allocated delalloc blocks with IOMAP_F_NEW so we punch + * them out if the write happens to fail. + */ + iomap->flags |= IOMAP_F_NEW; + trace_xfs_iomap_alloc(ip, offset, count, 0, &got); +done: + if (isnullstartblock(got.br_startblock)) + got.br_startblock = DELAYSTARTBLOCK; + + if (!got.br_startblock) { + error = xfs_alert_fsblock_zero(ip, &got); + if (error) + goto out_unlock; + } + + xfs_bmbt_to_iomap(ip, iomap, &got); + +out_unlock: + xfs_iunlock(ip, XFS_ILOCK_EXCL); + return error; +} + +/* + * Pass in a delayed allocate extent, convert it to real extents; + * return to the caller the extent we create which maps on top of + * the originating callers request. + * + * Called without a lock on the inode. + * + * We no longer bother to look at the incoming map - all we have to + * guarantee is that whatever we allocate fills the required range. + */ +int +xfs_iomap_write_allocate( + xfs_inode_t *ip, + int whichfork, + xfs_off_t offset, + xfs_bmbt_irec_t *imap, + unsigned int *cow_seq) +{ + xfs_mount_t *mp = ip->i_mount; + struct xfs_ifork *ifp = XFS_IFORK_PTR(ip, whichfork); + xfs_fileoff_t offset_fsb, last_block; + xfs_fileoff_t end_fsb, map_start_fsb; + xfs_filblks_t count_fsb; + xfs_trans_t *tp; + int nimaps; + int error = 0; + int flags = XFS_BMAPI_DELALLOC; + int nres; + + if (whichfork == XFS_COW_FORK) + flags |= XFS_BMAPI_COWFORK | XFS_BMAPI_PREALLOC; + + /* + * Make sure that the dquots are there. + */ + error = xfs_qm_dqattach(ip); + if (error) + return error; + + offset_fsb = XFS_B_TO_FSBT(mp, offset); + count_fsb = imap->br_blockcount; + map_start_fsb = imap->br_startoff; + + XFS_STATS_ADD(mp, xs_xstrat_bytes, XFS_FSB_TO_B(mp, count_fsb)); + + while (count_fsb != 0) { + /* + * Set up a transaction with which to allocate the + * backing store for the file. Do allocations in a + * loop until we get some space in the range we are + * interested in. The other space that might be allocated + * is in the delayed allocation extent on which we sit + * but before our buffer starts. + */ + nimaps = 0; + while (nimaps == 0) { + nres = XFS_EXTENTADD_SPACE_RES(mp, XFS_DATA_FORK); + /* + * We have already reserved space for the extent and any + * indirect blocks when creating the delalloc extent, + * there is no need to reserve space in this transaction + * again. + */ + error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, 0, + 0, XFS_TRANS_RESERVE, &tp); + if (error) + return error; + + xfs_ilock(ip, XFS_ILOCK_EXCL); + xfs_trans_ijoin(tp, ip, 0); + + /* + * it is possible that the extents have changed since + * we did the read call as we dropped the ilock for a + * while. We have to be careful about truncates or hole + * punchs here - we are not allowed to allocate + * non-delalloc blocks here. + * + * The only protection against truncation is the pages + * for the range we are being asked to convert are + * locked and hence a truncate will block on them + * first. + * + * As a result, if we go beyond the range we really + * need and hit an delalloc extent boundary followed by + * a hole while we have excess blocks in the map, we + * will fill the hole incorrectly and overrun the + * transaction reservation. + * + * Using a single map prevents this as we are forced to + * check each map we look for overlap with the desired + * range and abort as soon as we find it. Also, given + * that we only return a single map, having one beyond + * what we can return is probably a bit silly. + * + * We also need to check that we don't go beyond EOF; + * this is a truncate optimisation as a truncate sets + * the new file size before block on the pages we + * currently have locked under writeback. Because they + * are about to be tossed, we don't need to write them + * back.... + */ + nimaps = 1; + end_fsb = XFS_B_TO_FSB(mp, XFS_ISIZE(ip)); + error = xfs_bmap_last_offset(ip, &last_block, + XFS_DATA_FORK); + if (error) + goto trans_cancel; + + last_block = XFS_FILEOFF_MAX(last_block, end_fsb); + if ((map_start_fsb + count_fsb) > last_block) { + count_fsb = last_block - map_start_fsb; + if (count_fsb == 0) { + error = -EAGAIN; + goto trans_cancel; + } + } + + /* + * From this point onwards we overwrite the imap + * pointer that the caller gave to us. + */ + error = xfs_bmapi_write(tp, ip, map_start_fsb, + count_fsb, flags, nres, imap, + &nimaps); + if (error) + goto trans_cancel; + + error = xfs_trans_commit(tp); + if (error) + goto error0; + + if (whichfork == XFS_COW_FORK) + *cow_seq = READ_ONCE(ifp->if_seq); + xfs_iunlock(ip, XFS_ILOCK_EXCL); + } + + /* + * See if we were able to allocate an extent that + * covers at least part of the callers request + */ + if (!(imap->br_startblock || XFS_IS_REALTIME_INODE(ip))) + return xfs_alert_fsblock_zero(ip, imap); + + if ((offset_fsb >= imap->br_startoff) && + (offset_fsb < (imap->br_startoff + + imap->br_blockcount))) { + XFS_STATS_INC(mp, xs_xstrat_quick); + return 0; + } + + /* + * So far we have not mapped the requested part of the + * file, just surrounding data, try again. + */ + count_fsb -= imap->br_blockcount; + map_start_fsb = imap->br_startoff + imap->br_blockcount; + } + +trans_cancel: + xfs_trans_cancel(tp); +error0: + xfs_iunlock(ip, XFS_ILOCK_EXCL); + return error; +} + +int +xfs_iomap_write_unwritten( + xfs_inode_t *ip, + xfs_off_t offset, + xfs_off_t count, + bool update_isize) +{ + xfs_mount_t *mp = ip->i_mount; + xfs_fileoff_t offset_fsb; + xfs_filblks_t count_fsb; + xfs_filblks_t numblks_fsb; + int nimaps; + xfs_trans_t *tp; + xfs_bmbt_irec_t imap; + struct inode *inode = VFS_I(ip); + xfs_fsize_t i_size; + uint resblks; + int error; + + trace_xfs_unwritten_convert(ip, offset, count); + + offset_fsb = XFS_B_TO_FSBT(mp, offset); + count_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)offset + count); + count_fsb = (xfs_filblks_t)(count_fsb - offset_fsb); + + /* + * Reserve enough blocks in this transaction for two complete extent + * btree splits. We may be converting the middle part of an unwritten + * extent and in this case we will insert two new extents in the btree + * each of which could cause a full split. + * + * This reservation amount will be used in the first call to + * xfs_bmbt_split() to select an AG with enough space to satisfy the + * rest of the operation. + */ + resblks = XFS_DIOSTRAT_SPACE_RES(mp, 0) << 1; + + do { + /* + * Set up a transaction to convert the range of extents + * from unwritten to real. Do allocations in a loop until + * we have covered the range passed in. + * + * Note that we can't risk to recursing back into the filesystem + * here as we might be asked to write out the same inode that we + * complete here and might deadlock on the iolock. + */ + error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, resblks, 0, + XFS_TRANS_RESERVE | XFS_TRANS_NOFS, &tp); + if (error) + return error; + + xfs_ilock(ip, XFS_ILOCK_EXCL); + xfs_trans_ijoin(tp, ip, 0); + + /* + * Modify the unwritten extent state of the buffer. + */ + nimaps = 1; + error = xfs_bmapi_write(tp, ip, offset_fsb, count_fsb, + XFS_BMAPI_CONVERT, resblks, &imap, + &nimaps); + if (error) + goto error_on_bmapi_transaction; + + /* + * Log the updated inode size as we go. We have to be careful + * to only log it up to the actual write offset if it is + * halfway into a block. + */ + i_size = XFS_FSB_TO_B(mp, offset_fsb + count_fsb); + if (i_size > offset + count) + i_size = offset + count; + if (update_isize && i_size > i_size_read(inode)) + i_size_write(inode, i_size); + i_size = xfs_new_eof(ip, i_size); + if (i_size) { + ip->i_d.di_size = i_size; + xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE); + } + + error = xfs_trans_commit(tp); + xfs_iunlock(ip, XFS_ILOCK_EXCL); + if (error) + return error; + + if (!(imap.br_startblock || XFS_IS_REALTIME_INODE(ip))) + return xfs_alert_fsblock_zero(ip, &imap); + + if ((numblks_fsb = imap.br_blockcount) == 0) { + /* + * The numblks_fsb value should always get + * smaller, otherwise the loop is stuck. + */ + ASSERT(imap.br_blockcount); + break; + } + offset_fsb += numblks_fsb; + count_fsb -= numblks_fsb; + } while (count_fsb > 0); + + return 0; + +error_on_bmapi_transaction: + xfs_trans_cancel(tp); + xfs_iunlock(ip, XFS_ILOCK_EXCL); + return error; +} + +static inline bool +imap_needs_alloc( + struct inode *inode, + struct xfs_bmbt_irec *imap, + int nimaps) +{ + return !nimaps || + imap->br_startblock == HOLESTARTBLOCK || + imap->br_startblock == DELAYSTARTBLOCK || + (IS_DAX(inode) && imap->br_state == XFS_EXT_UNWRITTEN); +} + +static inline bool +needs_cow_for_zeroing( + struct xfs_bmbt_irec *imap, + int nimaps) +{ + return nimaps && + imap->br_startblock != HOLESTARTBLOCK && + imap->br_state != XFS_EXT_UNWRITTEN; +} + +static int +xfs_ilock_for_iomap( + struct xfs_inode *ip, + unsigned flags, + unsigned *lockmode) +{ + unsigned mode = XFS_ILOCK_SHARED; + bool is_write = flags & (IOMAP_WRITE | IOMAP_ZERO); + + /* + * COW writes may allocate delalloc space or convert unwritten COW + * extents, so we need to make sure to take the lock exclusively here. + */ + if (xfs_is_reflink_inode(ip) && is_write) { + /* + * FIXME: It could still overwrite on unshared extents and not + * need allocation. + */ + if (flags & IOMAP_NOWAIT) + return -EAGAIN; + mode = XFS_ILOCK_EXCL; + } + + /* + * Extents not yet cached requires exclusive access, don't block. This + * is an opencoded xfs_ilock_data_map_shared() call but with + * non-blocking behaviour. + */ + if (!(ip->i_df.if_flags & XFS_IFEXTENTS)) { + if (flags & IOMAP_NOWAIT) + return -EAGAIN; + mode = XFS_ILOCK_EXCL; + } + +relock: + if (flags & IOMAP_NOWAIT) { + if (!xfs_ilock_nowait(ip, mode)) + return -EAGAIN; + } else { + xfs_ilock(ip, mode); + } + + /* + * The reflink iflag could have changed since the earlier unlocked + * check, so if we got ILOCK_SHARED for a write and but we're now a + * reflink inode we have to switch to ILOCK_EXCL and relock. + */ + if (mode == XFS_ILOCK_SHARED && is_write && xfs_is_reflink_inode(ip)) { + xfs_iunlock(ip, mode); + mode = XFS_ILOCK_EXCL; + goto relock; + } + + *lockmode = mode; + return 0; +} + +static int +xfs_file_iomap_begin( + struct inode *inode, + loff_t offset, + loff_t length, + unsigned flags, + struct iomap *iomap) +{ + struct xfs_inode *ip = XFS_I(inode); + struct xfs_mount *mp = ip->i_mount; + struct xfs_bmbt_irec imap; + xfs_fileoff_t offset_fsb, end_fsb; + int nimaps = 1, error = 0; + bool shared = false, trimmed = false; + unsigned lockmode; + + if (XFS_FORCED_SHUTDOWN(mp)) + return -EIO; + + if (((flags & (IOMAP_WRITE | IOMAP_DIRECT)) == IOMAP_WRITE) && + !IS_DAX(inode) && !xfs_get_extsz_hint(ip)) { + /* Reserve delalloc blocks for regular writeback. */ + return xfs_file_iomap_begin_delay(inode, offset, length, iomap); + } + + /* + * Lock the inode in the manner required for the specified operation and + * check for as many conditions that would result in blocking as + * possible. This removes most of the non-blocking checks from the + * mapping code below. + */ + error = xfs_ilock_for_iomap(ip, flags, &lockmode); + if (error) + return error; + + ASSERT(offset <= mp->m_super->s_maxbytes); + if (offset > mp->m_super->s_maxbytes - length) + length = mp->m_super->s_maxbytes - offset; + offset_fsb = XFS_B_TO_FSBT(mp, offset); + end_fsb = XFS_B_TO_FSB(mp, offset + length); + + error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb, &imap, + &nimaps, 0); + if (error) + goto out_unlock; + + if (flags & IOMAP_REPORT) { + /* Trim the mapping to the nearest shared extent boundary. */ + error = xfs_reflink_trim_around_shared(ip, &imap, &shared, + &trimmed); + if (error) + goto out_unlock; + } + + /* Non-modifying mapping requested, so we are done */ + if (!(flags & (IOMAP_WRITE | IOMAP_ZERO))) + goto out_found; + + /* + * Break shared extents if necessary. Checks for non-blocking IO have + * been done up front, so we don't need to do them here. + */ + if (xfs_is_reflink_inode(ip)) { + /* if zeroing doesn't need COW allocation, then we are done. */ + if ((flags & IOMAP_ZERO) && + !needs_cow_for_zeroing(&imap, nimaps)) + goto out_found; + + if (flags & IOMAP_DIRECT) { + /* may drop and re-acquire the ilock */ + error = xfs_reflink_allocate_cow(ip, &imap, &shared, + &lockmode); + if (error) + goto out_unlock; + } else { + error = xfs_reflink_reserve_cow(ip, &imap, &shared); + if (error) + goto out_unlock; + } + + end_fsb = imap.br_startoff + imap.br_blockcount; + length = XFS_FSB_TO_B(mp, end_fsb) - offset; + } + + /* Don't need to allocate over holes when doing zeroing operations. */ + if (flags & IOMAP_ZERO) + goto out_found; + + if (!imap_needs_alloc(inode, &imap, nimaps)) + goto out_found; + + /* If nowait is set bail since we are going to make allocations. */ + if (flags & IOMAP_NOWAIT) { + error = -EAGAIN; + goto out_unlock; + } + + /* + * We cap the maximum length we map to a sane size to keep the chunks + * of work done where somewhat symmetric with the work writeback does. + * This is a completely arbitrary number pulled out of thin air as a + * best guess for initial testing. + * + * Note that the values needs to be less than 32-bits wide until the + * lower level functions are updated. + */ + length = min_t(loff_t, length, 1024 * PAGE_SIZE); + + /* + * xfs_iomap_write_direct() expects the shared lock. It is unlocked on + * return. + */ + if (lockmode == XFS_ILOCK_EXCL) + xfs_ilock_demote(ip, lockmode); + error = xfs_iomap_write_direct(ip, offset, length, &imap, + nimaps); + if (error) + return error; + + iomap->flags |= IOMAP_F_NEW; + trace_xfs_iomap_alloc(ip, offset, length, 0, &imap); + +out_finish: + if (xfs_ipincount(ip) && (ip->i_itemp->ili_fsync_fields + & ~XFS_ILOG_TIMESTAMP)) + iomap->flags |= IOMAP_F_DIRTY; + + xfs_bmbt_to_iomap(ip, iomap, &imap); + + if (shared) + iomap->flags |= IOMAP_F_SHARED; + return 0; + +out_found: + ASSERT(nimaps); + xfs_iunlock(ip, lockmode); + trace_xfs_iomap_found(ip, offset, length, 0, &imap); + goto out_finish; + +out_unlock: + xfs_iunlock(ip, lockmode); + return error; +} + +static int +xfs_file_iomap_end_delalloc( + struct xfs_inode *ip, + loff_t offset, + loff_t length, + ssize_t written, + struct iomap *iomap) +{ + struct xfs_mount *mp = ip->i_mount; + xfs_fileoff_t start_fsb; + xfs_fileoff_t end_fsb; + int error = 0; + + /* + * Behave as if the write failed if drop writes is enabled. Set the NEW + * flag to force delalloc cleanup. + */ + if (XFS_TEST_ERROR(false, mp, XFS_ERRTAG_DROP_WRITES)) { + iomap->flags |= IOMAP_F_NEW; + written = 0; + } + + /* + * start_fsb refers to the first unused block after a short write. If + * nothing was written, round offset down to point at the first block in + * the range. + */ + if (unlikely(!written)) + start_fsb = XFS_B_TO_FSBT(mp, offset); + else + start_fsb = XFS_B_TO_FSB(mp, offset + written); + end_fsb = XFS_B_TO_FSB(mp, offset + length); + + /* + * Trim delalloc blocks if they were allocated by this write and we + * didn't manage to write the whole range. + * + * We don't need to care about racing delalloc as we hold i_mutex + * across the reserve/allocate/unreserve calls. If there are delalloc + * blocks in the range, they are ours. + */ + if ((iomap->flags & IOMAP_F_NEW) && start_fsb < end_fsb) { + truncate_pagecache_range(VFS_I(ip), XFS_FSB_TO_B(mp, start_fsb), + XFS_FSB_TO_B(mp, end_fsb) - 1); + + error = xfs_bmap_punch_delalloc_range(ip, start_fsb, + end_fsb - start_fsb); + if (error && !XFS_FORCED_SHUTDOWN(mp)) { + xfs_alert(mp, "%s: unable to clean up ino %lld", + __func__, ip->i_ino); + return error; + } + } + + return 0; +} + +static int +xfs_file_iomap_end( + struct inode *inode, + loff_t offset, + loff_t length, + ssize_t written, + unsigned flags, + struct iomap *iomap) +{ + if ((flags & IOMAP_WRITE) && iomap->type == IOMAP_DELALLOC) + return xfs_file_iomap_end_delalloc(XFS_I(inode), offset, + length, written, iomap); + return 0; +} + +const struct iomap_ops xfs_iomap_ops = { + .iomap_begin = xfs_file_iomap_begin, + .iomap_end = xfs_file_iomap_end, +}; + +static int +xfs_xattr_iomap_begin( + struct inode *inode, + loff_t offset, + loff_t length, + unsigned flags, + struct iomap *iomap) +{ + struct xfs_inode *ip = XFS_I(inode); + struct xfs_mount *mp = ip->i_mount; + xfs_fileoff_t offset_fsb = XFS_B_TO_FSBT(mp, offset); + xfs_fileoff_t end_fsb = XFS_B_TO_FSB(mp, offset + length); + struct xfs_bmbt_irec imap; + int nimaps = 1, error = 0; + unsigned lockmode; + + if (XFS_FORCED_SHUTDOWN(mp)) + return -EIO; + + lockmode = xfs_ilock_attr_map_shared(ip); + + /* if there are no attribute fork or extents, return ENOENT */ + if (!XFS_IFORK_Q(ip) || !ip->i_d.di_anextents) { + error = -ENOENT; + goto out_unlock; + } + + ASSERT(ip->i_d.di_aformat != XFS_DINODE_FMT_LOCAL); + error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb, &imap, + &nimaps, XFS_BMAPI_ATTRFORK); +out_unlock: + xfs_iunlock(ip, lockmode); + + if (!error) { + ASSERT(nimaps); + xfs_bmbt_to_iomap(ip, iomap, &imap); + } + + return error; +} + +const struct iomap_ops xfs_xattr_iomap_ops = { + .iomap_begin = xfs_xattr_iomap_begin, +}; |