1 // SPDX-License-Identifier: GPL-2.0
3 * Copyright (c) 2000-2005 Silicon Graphics, Inc.
4 * Copyright (c) 2016-2018 Christoph Hellwig.
8 #include "xfs_shared.h"
9 #include "xfs_format.h"
10 #include "xfs_log_format.h"
11 #include "xfs_trans_resv.h"
12 #include "xfs_mount.h"
13 #include "xfs_inode.h"
14 #include "xfs_trans.h"
15 #include "xfs_iomap.h"
16 #include "xfs_trace.h"
18 #include "xfs_bmap_util.h"
19 #include "xfs_reflink.h"
21 struct xfs_writepage_ctx {
22 struct iomap_writepage_ctx ctx;
23 unsigned int data_seq;
27 static inline struct xfs_writepage_ctx *
28 XFS_WPC(struct iomap_writepage_ctx *ctx)
30 return container_of(ctx, struct xfs_writepage_ctx, ctx);
34 * Fast and loose check if this write could update the on-disk inode size.
36 static inline bool xfs_ioend_is_append(struct iomap_ioend *ioend)
38 return ioend->io_offset + ioend->io_size >
39 XFS_I(ioend->io_inode)->i_d.di_size;
43 xfs_setfilesize_trans_alloc(
44 struct iomap_ioend *ioend)
46 struct xfs_mount *mp = XFS_I(ioend->io_inode)->i_mount;
50 error = xfs_trans_alloc(mp, &M_RES(mp)->tr_fsyncts, 0, 0, 0, &tp);
54 ioend->io_private = tp;
57 * We may pass freeze protection with a transaction. So tell lockdep
60 __sb_writers_release(ioend->io_inode->i_sb, SB_FREEZE_FS);
62 * We hand off the transaction to the completion thread now, so
63 * clear the flag here.
65 xfs_trans_clear_context(tp);
70 * Update on-disk file size now that data has been written to disk.
81 xfs_ilock(ip, XFS_ILOCK_EXCL);
82 isize = xfs_new_eof(ip, offset + size);
84 xfs_iunlock(ip, XFS_ILOCK_EXCL);
89 trace_xfs_setfilesize(ip, offset, size);
91 ip->i_d.di_size = isize;
92 xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
93 xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
95 return xfs_trans_commit(tp);
100 struct xfs_inode *ip,
104 struct xfs_mount *mp = ip->i_mount;
105 struct xfs_trans *tp;
108 error = xfs_trans_alloc(mp, &M_RES(mp)->tr_fsyncts, 0, 0, 0, &tp);
112 return __xfs_setfilesize(ip, tp, offset, size);
116 xfs_setfilesize_ioend(
117 struct iomap_ioend *ioend,
120 struct xfs_inode *ip = XFS_I(ioend->io_inode);
121 struct xfs_trans *tp = ioend->io_private;
124 * The transaction may have been allocated in the I/O submission thread,
125 * thus we need to mark ourselves as being in a transaction manually.
126 * Similarly for freeze protection.
128 xfs_trans_set_context(tp);
129 __sb_writers_acquired(VFS_I(ip)->i_sb, SB_FREEZE_FS);
131 /* we abort the update if there was an IO error */
133 xfs_trans_cancel(tp);
137 return __xfs_setfilesize(ip, tp, ioend->io_offset, ioend->io_size);
141 * IO write completion.
145 struct iomap_ioend *ioend)
147 struct xfs_inode *ip = XFS_I(ioend->io_inode);
148 xfs_off_t offset = ioend->io_offset;
149 size_t size = ioend->io_size;
150 unsigned int nofs_flag;
154 * We can allocate memory here while doing writeback on behalf of
155 * memory reclaim. To avoid memory allocation deadlocks set the
156 * task-wide nofs context for the following operations.
158 nofs_flag = memalloc_nofs_save();
161 * Just clean up the in-memory strutures if the fs has been shut down.
163 if (XFS_FORCED_SHUTDOWN(ip->i_mount)) {
169 * Clean up any COW blocks on an I/O error.
171 error = blk_status_to_errno(ioend->io_bio->bi_status);
172 if (unlikely(error)) {
173 if (ioend->io_flags & IOMAP_F_SHARED)
174 xfs_reflink_cancel_cow_range(ip, offset, size, true);
179 * Success: commit the COW or unwritten blocks if needed.
181 if (ioend->io_flags & IOMAP_F_SHARED)
182 error = xfs_reflink_end_cow(ip, offset, size);
183 else if (ioend->io_type == IOMAP_UNWRITTEN)
184 error = xfs_iomap_write_unwritten(ip, offset, size, false);
186 ASSERT(!xfs_ioend_is_append(ioend) || ioend->io_private);
189 if (ioend->io_private)
190 error = xfs_setfilesize_ioend(ioend, error);
191 iomap_finish_ioends(ioend, error);
192 memalloc_nofs_restore(nofs_flag);
196 * If the to be merged ioend has a preallocated transaction for file
197 * size updates we need to ensure the ioend it is merged into also
198 * has one. If it already has one we can simply cancel the transaction
199 * as it is guaranteed to be clean.
202 xfs_ioend_merge_private(
203 struct iomap_ioend *ioend,
204 struct iomap_ioend *next)
206 if (!ioend->io_private) {
207 ioend->io_private = next->io_private;
208 next->io_private = NULL;
210 xfs_setfilesize_ioend(next, -ECANCELED);
214 /* Finish all pending io completions. */
217 struct work_struct *work)
219 struct xfs_inode *ip =
220 container_of(work, struct xfs_inode, i_ioend_work);
221 struct iomap_ioend *ioend;
222 struct list_head tmp;
225 spin_lock_irqsave(&ip->i_ioend_lock, flags);
226 list_replace_init(&ip->i_ioend_list, &tmp);
227 spin_unlock_irqrestore(&ip->i_ioend_lock, flags);
229 iomap_sort_ioends(&tmp);
230 while ((ioend = list_first_entry_or_null(&tmp, struct iomap_ioend,
232 list_del_init(&ioend->io_list);
233 iomap_ioend_try_merge(ioend, &tmp, xfs_ioend_merge_private);
234 xfs_end_ioend(ioend);
238 static inline bool xfs_ioend_needs_workqueue(struct iomap_ioend *ioend)
240 return ioend->io_private ||
241 ioend->io_type == IOMAP_UNWRITTEN ||
242 (ioend->io_flags & IOMAP_F_SHARED);
249 struct iomap_ioend *ioend = bio->bi_private;
250 struct xfs_inode *ip = XFS_I(ioend->io_inode);
253 ASSERT(xfs_ioend_needs_workqueue(ioend));
255 spin_lock_irqsave(&ip->i_ioend_lock, flags);
256 if (list_empty(&ip->i_ioend_list))
257 WARN_ON_ONCE(!queue_work(ip->i_mount->m_unwritten_workqueue,
259 list_add_tail(&ioend->io_list, &ip->i_ioend_list);
260 spin_unlock_irqrestore(&ip->i_ioend_lock, flags);
264 * Fast revalidation of the cached writeback mapping. Return true if the current
265 * mapping is valid, false otherwise.
269 struct iomap_writepage_ctx *wpc,
270 struct xfs_inode *ip,
273 if (offset < wpc->iomap.offset ||
274 offset >= wpc->iomap.offset + wpc->iomap.length)
277 * If this is a COW mapping, it is sufficient to check that the mapping
278 * covers the offset. Be careful to check this first because the caller
279 * can revalidate a COW mapping without updating the data seqno.
281 if (wpc->iomap.flags & IOMAP_F_SHARED)
285 * This is not a COW mapping. Check the sequence number of the data fork
286 * because concurrent changes could have invalidated the extent. Check
287 * the COW fork because concurrent changes since the last time we
288 * checked (and found nothing at this offset) could have added
289 * overlapping blocks.
291 if (XFS_WPC(wpc)->data_seq != READ_ONCE(ip->i_df.if_seq))
293 if (xfs_inode_has_cow_data(ip) &&
294 XFS_WPC(wpc)->cow_seq != READ_ONCE(ip->i_cowfp->if_seq))
300 * Pass in a dellalloc extent and convert it to real extents, return the real
301 * extent that maps offset_fsb in wpc->iomap.
303 * The current page is held locked so nothing could have removed the block
304 * backing offset_fsb, although it could have moved from the COW to the data
305 * fork by another thread.
309 struct iomap_writepage_ctx *wpc,
310 struct xfs_inode *ip,
317 if (whichfork == XFS_COW_FORK)
318 seq = &XFS_WPC(wpc)->cow_seq;
320 seq = &XFS_WPC(wpc)->data_seq;
323 * Attempt to allocate whatever delalloc extent currently backs offset
324 * and put the result into wpc->iomap. Allocate in a loop because it
325 * may take several attempts to allocate real blocks for a contiguous
326 * delalloc extent if free space is sufficiently fragmented.
329 error = xfs_bmapi_convert_delalloc(ip, whichfork, offset,
333 } while (wpc->iomap.offset + wpc->iomap.length <= offset);
340 struct iomap_writepage_ctx *wpc,
344 struct xfs_inode *ip = XFS_I(inode);
345 struct xfs_mount *mp = ip->i_mount;
346 ssize_t count = i_blocksize(inode);
347 xfs_fileoff_t offset_fsb = XFS_B_TO_FSBT(mp, offset);
348 xfs_fileoff_t end_fsb = XFS_B_TO_FSB(mp, offset + count);
349 xfs_fileoff_t cow_fsb;
351 struct xfs_bmbt_irec imap;
352 struct xfs_iext_cursor icur;
356 if (XFS_FORCED_SHUTDOWN(mp))
360 * COW fork blocks can overlap data fork blocks even if the blocks
361 * aren't shared. COW I/O always takes precedent, so we must always
362 * check for overlap on reflink inodes unless the mapping is already a
363 * COW one, or the COW fork hasn't changed from the last time we looked
366 * It's safe to check the COW fork if_seq here without the ILOCK because
367 * we've indirectly protected against concurrent updates: writeback has
368 * the page locked, which prevents concurrent invalidations by reflink
369 * and directio and prevents concurrent buffered writes to the same
370 * page. Changes to if_seq always happen under i_lock, which protects
371 * against concurrent updates and provides a memory barrier on the way
372 * out that ensures that we always see the current value.
374 if (xfs_imap_valid(wpc, ip, offset))
378 * If we don't have a valid map, now it's time to get a new one for this
379 * offset. This will convert delayed allocations (including COW ones)
380 * into real extents. If we return without a valid map, it means we
381 * landed in a hole and we skip the block.
384 cow_fsb = NULLFILEOFF;
385 whichfork = XFS_DATA_FORK;
386 xfs_ilock(ip, XFS_ILOCK_SHARED);
387 ASSERT(ip->i_df.if_format != XFS_DINODE_FMT_BTREE ||
388 (ip->i_df.if_flags & XFS_IFEXTENTS));
391 * Check if this is offset is covered by a COW extents, and if yes use
392 * it directly instead of looking up anything in the data fork.
394 if (xfs_inode_has_cow_data(ip) &&
395 xfs_iext_lookup_extent(ip, ip->i_cowfp, offset_fsb, &icur, &imap))
396 cow_fsb = imap.br_startoff;
397 if (cow_fsb != NULLFILEOFF && cow_fsb <= offset_fsb) {
398 XFS_WPC(wpc)->cow_seq = READ_ONCE(ip->i_cowfp->if_seq);
399 xfs_iunlock(ip, XFS_ILOCK_SHARED);
401 whichfork = XFS_COW_FORK;
402 goto allocate_blocks;
406 * No COW extent overlap. Revalidate now that we may have updated
407 * ->cow_seq. If the data mapping is still valid, we're done.
409 if (xfs_imap_valid(wpc, ip, offset)) {
410 xfs_iunlock(ip, XFS_ILOCK_SHARED);
415 * If we don't have a valid map, now it's time to get a new one for this
416 * offset. This will convert delayed allocations (including COW ones)
419 if (!xfs_iext_lookup_extent(ip, &ip->i_df, offset_fsb, &icur, &imap))
420 imap.br_startoff = end_fsb; /* fake a hole past EOF */
421 XFS_WPC(wpc)->data_seq = READ_ONCE(ip->i_df.if_seq);
422 xfs_iunlock(ip, XFS_ILOCK_SHARED);
424 /* landed in a hole or beyond EOF? */
425 if (imap.br_startoff > offset_fsb) {
426 imap.br_blockcount = imap.br_startoff - offset_fsb;
427 imap.br_startoff = offset_fsb;
428 imap.br_startblock = HOLESTARTBLOCK;
429 imap.br_state = XFS_EXT_NORM;
433 * Truncate to the next COW extent if there is one. This is the only
434 * opportunity to do this because we can skip COW fork lookups for the
435 * subsequent blocks in the mapping; however, the requirement to treat
436 * the COW range separately remains.
438 if (cow_fsb != NULLFILEOFF &&
439 cow_fsb < imap.br_startoff + imap.br_blockcount)
440 imap.br_blockcount = cow_fsb - imap.br_startoff;
442 /* got a delalloc extent? */
443 if (imap.br_startblock != HOLESTARTBLOCK &&
444 isnullstartblock(imap.br_startblock))
445 goto allocate_blocks;
447 xfs_bmbt_to_iomap(ip, &wpc->iomap, &imap, 0);
448 trace_xfs_map_blocks_found(ip, offset, count, whichfork, &imap);
451 error = xfs_convert_blocks(wpc, ip, whichfork, offset);
454 * If we failed to find the extent in the COW fork we might have
455 * raced with a COW to data fork conversion or truncate.
456 * Restart the lookup to catch the extent in the data fork for
457 * the former case, but prevent additional retries to avoid
458 * looping forever for the latter case.
460 if (error == -EAGAIN && whichfork == XFS_COW_FORK && !retries++)
462 ASSERT(error != -EAGAIN);
467 * Due to merging the return real extent might be larger than the
468 * original delalloc one. Trim the return extent to the next COW
469 * boundary again to force a re-lookup.
471 if (whichfork != XFS_COW_FORK && cow_fsb != NULLFILEOFF) {
472 loff_t cow_offset = XFS_FSB_TO_B(mp, cow_fsb);
474 if (cow_offset < wpc->iomap.offset + wpc->iomap.length)
475 wpc->iomap.length = cow_offset - wpc->iomap.offset;
478 ASSERT(wpc->iomap.offset <= offset);
479 ASSERT(wpc->iomap.offset + wpc->iomap.length > offset);
480 trace_xfs_map_blocks_alloc(ip, offset, count, whichfork, &imap);
486 struct iomap_ioend *ioend,
489 unsigned int nofs_flag;
492 * We can allocate memory here while doing writeback on behalf of
493 * memory reclaim. To avoid memory allocation deadlocks set the
494 * task-wide nofs context for the following operations.
496 nofs_flag = memalloc_nofs_save();
498 /* Convert CoW extents to regular */
499 if (!status && (ioend->io_flags & IOMAP_F_SHARED)) {
500 status = xfs_reflink_convert_cow(XFS_I(ioend->io_inode),
501 ioend->io_offset, ioend->io_size);
504 /* Reserve log space if we might write beyond the on-disk inode size. */
506 ((ioend->io_flags & IOMAP_F_SHARED) ||
507 ioend->io_type != IOMAP_UNWRITTEN) &&
508 xfs_ioend_is_append(ioend) &&
510 status = xfs_setfilesize_trans_alloc(ioend);
512 memalloc_nofs_restore(nofs_flag);
514 if (xfs_ioend_needs_workqueue(ioend))
515 ioend->io_bio->bi_end_io = xfs_end_bio;
520 * If the page has delalloc blocks on it, we need to punch them out before we
521 * invalidate the page. If we don't, we leave a stale delalloc mapping on the
522 * inode that can trip up a later direct I/O read operation on the same region.
524 * We prevent this by truncating away the delalloc regions on the page. Because
525 * they are delalloc, we can do this without needing a transaction. Indeed - if
526 * we get ENOSPC errors, we have to be able to do this truncation without a
527 * transaction as there is no space left for block reservation (typically why we
528 * see a ENOSPC in writeback).
535 struct inode *inode = page->mapping->host;
536 struct xfs_inode *ip = XFS_I(inode);
537 struct xfs_mount *mp = ip->i_mount;
538 unsigned int pageoff = offset_in_page(fileoff);
539 xfs_fileoff_t start_fsb = XFS_B_TO_FSBT(mp, fileoff);
540 xfs_fileoff_t pageoff_fsb = XFS_B_TO_FSBT(mp, pageoff);
543 if (XFS_FORCED_SHUTDOWN(mp))
546 xfs_alert_ratelimited(mp,
547 "page discard on page "PTR_FMT", inode 0x%llx, offset %llu.",
548 page, ip->i_ino, fileoff);
550 error = xfs_bmap_punch_delalloc_range(ip, start_fsb,
551 i_blocks_per_page(inode, page) - pageoff_fsb);
552 if (error && !XFS_FORCED_SHUTDOWN(mp))
553 xfs_alert(mp, "page discard unable to remove delalloc mapping.");
555 iomap_invalidatepage(page, pageoff, PAGE_SIZE - pageoff);
558 static const struct iomap_writeback_ops xfs_writeback_ops = {
559 .map_blocks = xfs_map_blocks,
560 .prepare_ioend = xfs_prepare_ioend,
561 .discard_page = xfs_discard_page,
567 struct writeback_control *wbc)
569 struct xfs_writepage_ctx wpc = { };
571 if (WARN_ON_ONCE(current->journal_info)) {
572 redirty_page_for_writepage(wbc, page);
577 return iomap_writepage(page, wbc, &wpc.ctx, &xfs_writeback_ops);
582 struct address_space *mapping,
583 struct writeback_control *wbc)
585 struct xfs_writepage_ctx wpc = { };
588 * Writing back data in a transaction context can result in recursive
589 * transactions. This is bad, so issue a warning and get out of here.
591 if (WARN_ON_ONCE(current->journal_info))
594 xfs_iflags_clear(XFS_I(mapping->host), XFS_ITRUNCATED);
595 return iomap_writepages(mapping, wbc, &wpc.ctx, &xfs_writeback_ops);
600 struct address_space *mapping,
601 struct writeback_control *wbc)
603 struct xfs_inode *ip = XFS_I(mapping->host);
605 xfs_iflags_clear(ip, XFS_ITRUNCATED);
606 return dax_writeback_mapping_range(mapping,
607 xfs_inode_buftarg(ip)->bt_daxdev, wbc);
612 struct address_space *mapping,
615 struct xfs_inode *ip = XFS_I(mapping->host);
617 trace_xfs_vm_bmap(ip);
620 * The swap code (ab-)uses ->bmap to get a block mapping and then
621 * bypasses the file system for actual I/O. We really can't allow
622 * that on reflinks inodes, so we have to skip out here. And yes,
623 * 0 is the magic code for a bmap error.
625 * Since we don't pass back blockdev info, we can't return bmap
626 * information for rt files either.
628 if (xfs_is_cow_inode(ip) || XFS_IS_REALTIME_INODE(ip))
630 return iomap_bmap(mapping, block, &xfs_read_iomap_ops);
638 return iomap_readpage(page, &xfs_read_iomap_ops);
643 struct readahead_control *rac)
645 iomap_readahead(rac, &xfs_read_iomap_ops);
649 xfs_iomap_swapfile_activate(
650 struct swap_info_struct *sis,
651 struct file *swap_file,
654 sis->bdev = xfs_inode_buftarg(XFS_I(file_inode(swap_file)))->bt_bdev;
655 return iomap_swapfile_activate(sis, swap_file, span,
656 &xfs_read_iomap_ops);
659 const struct address_space_operations xfs_address_space_operations = {
660 .readpage = xfs_vm_readpage,
661 .readahead = xfs_vm_readahead,
662 .writepage = xfs_vm_writepage,
663 .writepages = xfs_vm_writepages,
664 .set_page_dirty = iomap_set_page_dirty,
665 .releasepage = iomap_releasepage,
666 .invalidatepage = iomap_invalidatepage,
668 .direct_IO = noop_direct_IO,
669 .migratepage = iomap_migrate_page,
670 .is_partially_uptodate = iomap_is_partially_uptodate,
671 .error_remove_page = generic_error_remove_page,
672 .swap_activate = xfs_iomap_swapfile_activate,
675 const struct address_space_operations xfs_dax_aops = {
676 .writepages = xfs_dax_writepages,
677 .direct_IO = noop_direct_IO,
678 .set_page_dirty = noop_set_page_dirty,
679 .invalidatepage = noop_invalidatepage,
680 .swap_activate = xfs_iomap_swapfile_activate,