/* * Copyright (c) 2000-2006 Silicon Graphics, Inc. * All Rights Reserved. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License as * published by the Free Software Foundation. * * This program is distributed in the hope that it would be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */ #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_error.h" #include "xfs_trans.h" #include "xfs_trans_space.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" #define XFS_WRITEIO_ALIGN(mp,off) (((off) >> mp->m_writeio_log) \ << mp->m_writeio_log) #define XFS_WRITE_IMAPS XFS_BMAP_MAX_NMAP STATIC int xfs_iomap_eof_align_last_fsb( xfs_mount_t *mp, xfs_inode_t *ip, xfs_extlen_t extsize, xfs_fileoff_t *last_fsb) { xfs_extlen_t align = 0; int eof, error; 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; } if (align) { xfs_fileoff_t new_last_fsb = roundup_64(*last_fsb, align); 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_fsblock_t firstfsb; xfs_extlen_t extsz, temp; int nimaps; int quota_flag; int rt; xfs_trans_t *tp; xfs_bmap_free_t free_list; uint qblocks, resblks, resrtextents; int committed; int error; int lockmode; 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(mp, 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 = count_fsb; if (unlikely(extsz)) { if ((temp = do_mod(offset_fsb, extsz))) resaligned += temp; if ((temp = do_mod(resaligned, extsz))) resaligned += extsz - temp; } 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, 0); if (error) return error; /* * Allocate and setup the transaction */ tp = xfs_trans_alloc(mp, XFS_TRANS_DIOSTRAT); error = xfs_trans_reserve(tp, &M_RES(mp)->tr_write, resblks, resrtextents); /* * Check for running out of space, note: need lock to return */ if (error) { xfs_trans_cancel(tp); 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. */ xfs_bmap_init(&free_list, &firstfsb); nimaps = 1; error = xfs_bmapi_write(tp, ip, offset_fsb, count_fsb, XFS_BMAPI_PREALLOC, &firstfsb, 0, imap, &nimaps, &free_list); if (error) goto out_bmap_cancel; /* * Complete the transaction */ error = xfs_bmap_finish(&tp, &free_list, &committed); if (error) goto out_bmap_cancel; 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_bmap_cancel: xfs_bmap_cancel(&free_list); xfs_trans_unreserve_quota_nblks(tp, ip, (long)qblocks, 0, quota_flag); out_trans_cancel: xfs_trans_cancel(tp); goto out_unlock; } /* * If the caller is doing a write at the end of the file, then extend the * allocation out to the file system's write iosize. We clean up any extra * space left over when the file is closed in xfs_inactive(). * * If we find we already have delalloc preallocation beyond EOF, don't do more * preallocation as it it not needed. */ STATIC int xfs_iomap_eof_want_preallocate( xfs_mount_t *mp, xfs_inode_t *ip, xfs_off_t offset, size_t count, xfs_bmbt_irec_t *imap, int nimaps, int *prealloc) { xfs_fileoff_t start_fsb; xfs_filblks_t count_fsb; int n, error, imaps; int found_delalloc = 0; *prealloc = 0; if (offset + count <= XFS_ISIZE(ip)) return 0; /* * If the file is smaller than the minimum prealloc and we are using * dynamic preallocation, don't do any preallocation at all as it is * likely this is the only write to the file that is going to be done. */ if (!(mp->m_flags & XFS_MOUNT_DFLT_IOSIZE) && XFS_ISIZE(ip) < XFS_FSB_TO_B(mp, mp->m_writeio_blocks)) return 0; /* * If there are any real blocks past eof, then don't * do any speculative allocation. */ start_fsb = XFS_B_TO_FSBT(mp, ((xfs_ufsize_t)(offset + count - 1))); count_fsb = XFS_B_TO_FSB(mp, mp->m_super->s_maxbytes); while (count_fsb > 0) { imaps = nimaps; error = xfs_bmapi_read(ip, start_fsb, count_fsb, imap, &imaps, 0); if (error) return error; for (n = 0; n < imaps; n++) { if ((imap[n].br_startblock != HOLESTARTBLOCK) && (imap[n].br_startblock != DELAYSTARTBLOCK)) return 0; start_fsb += imap[n].br_blockcount; count_fsb -= imap[n].br_blockcount; if (imap[n].br_startblock == DELAYSTARTBLOCK) found_delalloc = 1; } } if (!found_delalloc) *prealloc = 1; return 0; } /* * 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 preceeding 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. */ STATIC xfs_fsblock_t xfs_iomap_eof_prealloc_initial_size( struct xfs_mount *mp, struct xfs_inode *ip, xfs_off_t offset, xfs_bmbt_irec_t *imap, int nimaps) { xfs_fileoff_t start_fsb; int imaps = 1; int error; ASSERT(nimaps >= imaps); /* if we are using a specific prealloc size, return now */ if (mp->m_flags & XFS_MOUNT_DFLT_IOSIZE) return 0; /* If the file is small, then use the minimum prealloc */ if (XFS_ISIZE(ip) < XFS_FSB_TO_B(mp, mp->m_dalign)) return 0; /* * As we write multiple pages, the offset will always align to the * start of a page and hence point to a hole at EOF. i.e. if the size is * 4096 bytes, we only have one block at FSB 0, but XFS_B_TO_FSB(4096) * will return FSB 1. Hence if there are blocks in the file, we want to * point to the block prior to the EOF block and not the hole that maps * directly at @offset. */ start_fsb = XFS_B_TO_FSB(mp, offset); if (start_fsb) start_fsb--; error = xfs_bmapi_read(ip, start_fsb, 1, imap, &imaps, XFS_BMAPI_ENTIRE); if (error) return 0; ASSERT(imaps == 1); if (imap[0].br_startblock == HOLESTARTBLOCK) return 0; if (imap[0].br_blockcount <= (MAXEXTLEN >> 1)) return imap[0].br_blockcount << 1; return XFS_B_TO_FSB(mp, offset); } 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 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. */ STATIC xfs_fsblock_t xfs_iomap_prealloc_size( struct xfs_mount *mp, struct xfs_inode *ip, xfs_off_t offset, struct xfs_bmbt_irec *imap, int nimaps) { xfs_fsblock_t alloc_blocks = 0; int shift = 0; int64_t freesp; xfs_fsblock_t qblocks; int qshift = 0; alloc_blocks = xfs_iomap_eof_prealloc_initial_size(mp, ip, offset, imap, nimaps); 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; } int xfs_iomap_write_delay( xfs_inode_t *ip, xfs_off_t offset, size_t count, xfs_bmbt_irec_t *ret_imap) { xfs_mount_t *mp = ip->i_mount; xfs_fileoff_t offset_fsb; xfs_fileoff_t last_fsb; xfs_off_t aligned_offset; xfs_fileoff_t ioalign; xfs_extlen_t extsz; int nimaps; xfs_bmbt_irec_t imap[XFS_WRITE_IMAPS]; int prealloc; int error; ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL)); /* * Make sure that the dquots are there. This doesn't hold * the ilock across a disk read. */ error = xfs_qm_dqattach_locked(ip, 0); if (error) return error; extsz = xfs_get_extsz_hint(ip); offset_fsb = XFS_B_TO_FSBT(mp, offset); error = xfs_iomap_eof_want_preallocate(mp, ip, offset, count, imap, XFS_WRITE_IMAPS, &prealloc); if (error) return error; retry: if (prealloc) { xfs_fsblock_t alloc_blocks; alloc_blocks = xfs_iomap_prealloc_size(mp, ip, offset, imap, XFS_WRITE_IMAPS); aligned_offset = XFS_WRITEIO_ALIGN(mp, (offset + count - 1)); ioalign = XFS_B_TO_FSBT(mp, aligned_offset); last_fsb = ioalign + alloc_blocks; } else { last_fsb = XFS_B_TO_FSB(mp, ((xfs_ufsize_t)(offset + count))); } if (prealloc || extsz) { error = xfs_iomap_eof_align_last_fsb(mp, ip, extsz, &last_fsb); if (error) return error; } /* * Make sure preallocation does not create extents beyond the range we * actually support in this filesystem. */ if (last_fsb > XFS_B_TO_FSB(mp, mp->m_super->s_maxbytes)) last_fsb = XFS_B_TO_FSB(mp, mp->m_super->s_maxbytes); ASSERT(last_fsb > offset_fsb); nimaps = XFS_WRITE_IMAPS; error = xfs_bmapi_delay(ip, offset_fsb, last_fsb - offset_fsb, imap, &nimaps, XFS_BMAPI_ENTIRE); switch (error) { case 0: case -ENOSPC: case -EDQUOT: break; default: return error; } /* * If bmapi returned us nothing, we got either ENOSPC or EDQUOT. Retry * without EOF preallocation. */ if (nimaps == 0) { trace_xfs_delalloc_enospc(ip, offset, count); if (prealloc) { prealloc = 0; error = 0; goto retry; } return error ? error : -ENOSPC; } if (!(imap[0].br_startblock || XFS_IS_REALTIME_INODE(ip))) return xfs_alert_fsblock_zero(ip, &imap[0]); /* * Tag the inode as speculatively preallocated so we can reclaim this * space on demand, if necessary. */ if (prealloc) xfs_inode_set_eofblocks_tag(ip); *ret_imap = imap[0]; return 0; } /* * 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, xfs_off_t offset, xfs_bmbt_irec_t *imap) { xfs_mount_t *mp = ip->i_mount; xfs_fileoff_t offset_fsb, last_block; xfs_fileoff_t end_fsb, map_start_fsb; xfs_fsblock_t first_block; xfs_bmap_free_t free_list; xfs_filblks_t count_fsb; xfs_trans_t *tp; int nimaps, committed; int error = 0; int nres; /* * Make sure that the dquots are there. */ error = xfs_qm_dqattach(ip, 0); 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(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) { tp = xfs_trans_alloc(mp, XFS_TRANS_STRAT_WRITE); tp->t_flags |= XFS_TRANS_RESERVE; nres = XFS_EXTENTADD_SPACE_RES(mp, XFS_DATA_FORK); error = xfs_trans_reserve(tp, &M_RES(mp)->tr_write, nres, 0); if (error) { xfs_trans_cancel(tp); return error; } xfs_ilock(ip, XFS_ILOCK_EXCL); xfs_trans_ijoin(tp, ip, 0); xfs_bmap_init(&free_list, &first_block); /* * 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, 0, &first_block, 1, imap, &nimaps, &free_list); if (error) goto trans_cancel; error = xfs_bmap_finish(&tp, &free_list, &committed); if (error) goto trans_cancel; error = xfs_trans_commit(tp); if (error) goto error0; 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(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_bmap_cancel(&free_list); 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) { xfs_mount_t *mp = ip->i_mount; xfs_fileoff_t offset_fsb; xfs_filblks_t count_fsb; xfs_filblks_t numblks_fsb; xfs_fsblock_t firstfsb; int nimaps; xfs_trans_t *tp; xfs_bmbt_irec_t imap; xfs_bmap_free_t free_list; xfs_fsize_t i_size; uint resblks; int committed; 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 open code the transaction allocation here * to pass KM_NOFS--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. */ sb_start_intwrite(mp->m_super); tp = _xfs_trans_alloc(mp, XFS_TRANS_STRAT_WRITE, KM_NOFS); tp->t_flags |= XFS_TRANS_RESERVE | XFS_TRANS_FREEZE_PROT; error = xfs_trans_reserve(tp, &M_RES(mp)->tr_write, resblks, 0); if (error) { xfs_trans_cancel(tp); return error; } xfs_ilock(ip, XFS_ILOCK_EXCL); xfs_trans_ijoin(tp, ip, 0); /* * Modify the unwritten extent state of the buffer. */ xfs_bmap_init(&free_list, &firstfsb); nimaps = 1; error = xfs_bmapi_write(tp, ip, offset_fsb, count_fsb, XFS_BMAPI_CONVERT, &firstfsb, 1, &imap, &nimaps, &free_list); 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; 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_bmap_finish(&tp, &free_list, &committed); if (error) goto error_on_bmapi_transaction; 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_bmap_cancel(&free_list); xfs_trans_cancel(tp); xfs_iunlock(ip, XFS_ILOCK_EXCL); return error; }