diff options
Diffstat (limited to 'fs/xfs/xfs_iomap.c')
-rw-r--r-- | fs/xfs/xfs_iomap.c | 206 |
1 files changed, 114 insertions, 92 deletions
diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c index 046469f..49f5492 100644 --- a/fs/xfs/xfs_iomap.c +++ b/fs/xfs/xfs_iomap.c @@ -1,20 +1,8 @@ +// SPDX-License-Identifier: GPL-2.0 /* * Copyright (c) 2000-2006 Silicon Graphics, Inc. * Copyright (c) 2016 Christoph Hellwig. * 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 <linux/iomap.h> #include "xfs.h" @@ -200,7 +188,7 @@ xfs_iomap_write_direct( goto out_unlock; } else { if (nmaps && (imap->br_startblock == HOLESTARTBLOCK)) - last_fsb = MIN(last_fsb, (xfs_fileoff_t) + last_fsb = min(last_fsb, (xfs_fileoff_t) imap->br_blockcount + imap->br_startoff); } @@ -224,7 +212,7 @@ xfs_iomap_write_direct( * necessary and move on to transaction setup. */ xfs_iunlock(ip, lockmode); - error = xfs_qm_dqattach(ip, 0); + error = xfs_qm_dqattach(ip); if (error) return error; @@ -488,8 +476,8 @@ xfs_iomap_prealloc_size( * 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); + alloc_blocks = min(alloc_blocks, qblocks); + shift = max(shift, qshift); if (shift) alloc_blocks >>= shift; @@ -576,7 +564,7 @@ xfs_file_iomap_begin_delay( goto done; } - error = xfs_qm_dqattach_locked(ip, 0); + error = xfs_qm_dqattach_locked(ip, false); if (error) goto out_unlock; @@ -692,7 +680,7 @@ xfs_iomap_write_allocate( /* * Make sure that the dquots are there. */ - error = xfs_qm_dqattach(ip, 0); + error = xfs_qm_dqattach(ip); if (error) return error; @@ -946,8 +934,11 @@ error_on_bmapi_transaction: return error; } -static inline bool imap_needs_alloc(struct inode *inode, - struct xfs_bmbt_irec *imap, int nimaps) +static inline bool +imap_needs_alloc( + struct inode *inode, + struct xfs_bmbt_irec *imap, + int nimaps) { return !nimaps || imap->br_startblock == HOLESTARTBLOCK || @@ -955,31 +946,58 @@ static inline bool imap_needs_alloc(struct inode *inode, (IS_DAX(inode) && imap->br_state == XFS_EXT_UNWRITTEN); } -static inline bool needs_cow_for_zeroing(struct xfs_bmbt_irec *imap, int nimaps) +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 inline bool need_excl_ilock(struct xfs_inode *ip, unsigned flags) +static int +xfs_ilock_for_iomap( + struct xfs_inode *ip, + unsigned flags, + unsigned *lockmode) { + unsigned mode = XFS_ILOCK_SHARED; + /* * 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) && (flags & (IOMAP_WRITE | IOMAP_ZERO))) - return true; + if (xfs_is_reflink_inode(ip) && (flags & (IOMAP_WRITE | IOMAP_ZERO))) { + /* + * 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() to cater for the + * 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_d.di_format == XFS_DINODE_FMT_BTREE && - !(ip->i_df.if_flags & XFS_IFEXTENTS)) - return true; - return false; + if (!(ip->i_df.if_flags & XFS_IFEXTENTS)) { + if (flags & IOMAP_NOWAIT) + return -EAGAIN; + mode = XFS_ILOCK_EXCL; + } + + if (flags & IOMAP_NOWAIT) { + if (!xfs_ilock_nowait(ip, mode)) + return -EAGAIN; + } else { + xfs_ilock(ip, mode); + } + + *lockmode = mode; + return 0; } static int @@ -1007,19 +1025,15 @@ xfs_file_iomap_begin( return xfs_file_iomap_begin_delay(inode, offset, length, iomap); } - if (need_excl_ilock(ip, flags)) - lockmode = XFS_ILOCK_EXCL; - else - lockmode = XFS_ILOCK_SHARED; - - if (flags & IOMAP_NOWAIT) { - if (!(ip->i_df.if_flags & XFS_IFEXTENTS)) - return -EAGAIN; - if (!xfs_ilock_nowait(ip, lockmode)) - return -EAGAIN; - } else { - xfs_ilock(ip, lockmode); - } + /* + * 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) @@ -1040,19 +1054,21 @@ xfs_file_iomap_begin( goto out_unlock; } - if (xfs_is_reflink_inode(ip) && - ((flags & IOMAP_WRITE) || - ((flags & IOMAP_ZERO) && needs_cow_for_zeroing(&imap, nimaps)))) { + /* 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) { - /* - * A reflinked inode will result in CoW alloc. - * FIXME: It could still overwrite on unshared extents - * and not need allocation. - */ - if (flags & IOMAP_NOWAIT) { - error = -EAGAIN; - goto out_unlock; - } /* may drop and re-acquire the ilock */ error = xfs_reflink_allocate_cow(ip, &imap, &shared, &lockmode); @@ -1068,46 +1084,45 @@ xfs_file_iomap_begin( length = XFS_FSB_TO_B(mp, end_fsb) - offset; } - if ((flags & IOMAP_WRITE) && imap_needs_alloc(inode, &imap, nimaps)) { - /* - * 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 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. - */ - 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; + /* Don't need to allocate over holes when doing zeroing operations. */ + if (flags & IOMAP_ZERO) + goto out_found; - iomap->flags = IOMAP_F_NEW; - trace_xfs_iomap_alloc(ip, offset, length, 0, &imap); - } else { - ASSERT(nimaps); + if (!imap_needs_alloc(inode, &imap, nimaps)) + goto out_found; - xfs_iunlock(ip, lockmode); - trace_xfs_iomap_found(ip, offset, length, 0, &imap); + /* 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; @@ -1117,6 +1132,13 @@ xfs_file_iomap_begin( 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; |