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_disk_size;
43 * Update on-disk file size now that data has been written to disk.
51 struct xfs_mount *mp = ip->i_mount;
56 error = xfs_trans_alloc(mp, &M_RES(mp)->tr_fsyncts, 0, 0, 0, &tp);
60 xfs_ilock(ip, XFS_ILOCK_EXCL);
61 isize = xfs_new_eof(ip, offset + size);
63 xfs_iunlock(ip, XFS_ILOCK_EXCL);
68 trace_xfs_setfilesize(ip, offset, size);
70 ip->i_disk_size = isize;
71 xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
72 xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
74 return xfs_trans_commit(tp);
78 * IO write completion.
82 struct iomap_ioend *ioend)
84 struct xfs_inode *ip = XFS_I(ioend->io_inode);
85 struct xfs_mount *mp = ip->i_mount;
86 xfs_off_t offset = ioend->io_offset;
87 size_t size = ioend->io_size;
88 unsigned int nofs_flag;
92 * We can allocate memory here while doing writeback on behalf of
93 * memory reclaim. To avoid memory allocation deadlocks set the
94 * task-wide nofs context for the following operations.
96 nofs_flag = memalloc_nofs_save();
99 * Just clean up the in-memory structures if the fs has been shut down.
101 if (xfs_is_shutdown(mp)) {
107 * Clean up all COW blocks and underlying data fork delalloc blocks on
108 * I/O error. The delalloc punch is required because this ioend was
109 * mapped to blocks in the COW fork and the associated pages are no
110 * longer dirty. If we don't remove delalloc blocks here, they become
111 * stale and can corrupt free space accounting on unmount.
113 error = blk_status_to_errno(ioend->io_bio->bi_status);
114 if (unlikely(error)) {
115 if (ioend->io_flags & IOMAP_F_SHARED) {
116 xfs_reflink_cancel_cow_range(ip, offset, size, true);
117 xfs_bmap_punch_delalloc_range(ip,
118 XFS_B_TO_FSBT(mp, offset),
119 XFS_B_TO_FSB(mp, size));
125 * Success: commit the COW or unwritten blocks if needed.
127 if (ioend->io_flags & IOMAP_F_SHARED)
128 error = xfs_reflink_end_cow(ip, offset, size);
129 else if (ioend->io_type == IOMAP_UNWRITTEN)
130 error = xfs_iomap_write_unwritten(ip, offset, size, false);
132 if (!error && xfs_ioend_is_append(ioend))
133 error = xfs_setfilesize(ip, ioend->io_offset, ioend->io_size);
135 iomap_finish_ioends(ioend, error);
136 memalloc_nofs_restore(nofs_flag);
139 /* Finish all pending io completions. */
142 struct work_struct *work)
144 struct xfs_inode *ip =
145 container_of(work, struct xfs_inode, i_ioend_work);
146 struct iomap_ioend *ioend;
147 struct list_head tmp;
150 spin_lock_irqsave(&ip->i_ioend_lock, flags);
151 list_replace_init(&ip->i_ioend_list, &tmp);
152 spin_unlock_irqrestore(&ip->i_ioend_lock, flags);
154 iomap_sort_ioends(&tmp);
155 while ((ioend = list_first_entry_or_null(&tmp, struct iomap_ioend,
157 list_del_init(&ioend->io_list);
158 iomap_ioend_try_merge(ioend, &tmp);
159 xfs_end_ioend(ioend);
167 struct iomap_ioend *ioend = bio->bi_private;
168 struct xfs_inode *ip = XFS_I(ioend->io_inode);
171 spin_lock_irqsave(&ip->i_ioend_lock, flags);
172 if (list_empty(&ip->i_ioend_list))
173 WARN_ON_ONCE(!queue_work(ip->i_mount->m_unwritten_workqueue,
175 list_add_tail(&ioend->io_list, &ip->i_ioend_list);
176 spin_unlock_irqrestore(&ip->i_ioend_lock, flags);
180 * Fast revalidation of the cached writeback mapping. Return true if the current
181 * mapping is valid, false otherwise.
185 struct iomap_writepage_ctx *wpc,
186 struct xfs_inode *ip,
189 if (offset < wpc->iomap.offset ||
190 offset >= wpc->iomap.offset + wpc->iomap.length)
193 * If this is a COW mapping, it is sufficient to check that the mapping
194 * covers the offset. Be careful to check this first because the caller
195 * can revalidate a COW mapping without updating the data seqno.
197 if (wpc->iomap.flags & IOMAP_F_SHARED)
201 * This is not a COW mapping. Check the sequence number of the data fork
202 * because concurrent changes could have invalidated the extent. Check
203 * the COW fork because concurrent changes since the last time we
204 * checked (and found nothing at this offset) could have added
205 * overlapping blocks.
207 if (XFS_WPC(wpc)->data_seq != READ_ONCE(ip->i_df.if_seq))
209 if (xfs_inode_has_cow_data(ip) &&
210 XFS_WPC(wpc)->cow_seq != READ_ONCE(ip->i_cowfp->if_seq))
216 * Pass in a dellalloc extent and convert it to real extents, return the real
217 * extent that maps offset_fsb in wpc->iomap.
219 * The current page is held locked so nothing could have removed the block
220 * backing offset_fsb, although it could have moved from the COW to the data
221 * fork by another thread.
225 struct iomap_writepage_ctx *wpc,
226 struct xfs_inode *ip,
233 if (whichfork == XFS_COW_FORK)
234 seq = &XFS_WPC(wpc)->cow_seq;
236 seq = &XFS_WPC(wpc)->data_seq;
239 * Attempt to allocate whatever delalloc extent currently backs offset
240 * and put the result into wpc->iomap. Allocate in a loop because it
241 * may take several attempts to allocate real blocks for a contiguous
242 * delalloc extent if free space is sufficiently fragmented.
245 error = xfs_bmapi_convert_delalloc(ip, whichfork, offset,
249 } while (wpc->iomap.offset + wpc->iomap.length <= offset);
256 struct iomap_writepage_ctx *wpc,
260 struct xfs_inode *ip = XFS_I(inode);
261 struct xfs_mount *mp = ip->i_mount;
262 ssize_t count = i_blocksize(inode);
263 xfs_fileoff_t offset_fsb = XFS_B_TO_FSBT(mp, offset);
264 xfs_fileoff_t end_fsb = XFS_B_TO_FSB(mp, offset + count);
265 xfs_fileoff_t cow_fsb;
267 struct xfs_bmbt_irec imap;
268 struct xfs_iext_cursor icur;
272 if (xfs_is_shutdown(mp))
276 * COW fork blocks can overlap data fork blocks even if the blocks
277 * aren't shared. COW I/O always takes precedent, so we must always
278 * check for overlap on reflink inodes unless the mapping is already a
279 * COW one, or the COW fork hasn't changed from the last time we looked
282 * It's safe to check the COW fork if_seq here without the ILOCK because
283 * we've indirectly protected against concurrent updates: writeback has
284 * the page locked, which prevents concurrent invalidations by reflink
285 * and directio and prevents concurrent buffered writes to the same
286 * page. Changes to if_seq always happen under i_lock, which protects
287 * against concurrent updates and provides a memory barrier on the way
288 * out that ensures that we always see the current value.
290 if (xfs_imap_valid(wpc, ip, offset))
294 * If we don't have a valid map, now it's time to get a new one for this
295 * offset. This will convert delayed allocations (including COW ones)
296 * into real extents. If we return without a valid map, it means we
297 * landed in a hole and we skip the block.
300 cow_fsb = NULLFILEOFF;
301 whichfork = XFS_DATA_FORK;
302 xfs_ilock(ip, XFS_ILOCK_SHARED);
303 ASSERT(!xfs_need_iread_extents(&ip->i_df));
306 * Check if this is offset is covered by a COW extents, and if yes use
307 * it directly instead of looking up anything in the data fork.
309 if (xfs_inode_has_cow_data(ip) &&
310 xfs_iext_lookup_extent(ip, ip->i_cowfp, offset_fsb, &icur, &imap))
311 cow_fsb = imap.br_startoff;
312 if (cow_fsb != NULLFILEOFF && cow_fsb <= offset_fsb) {
313 XFS_WPC(wpc)->cow_seq = READ_ONCE(ip->i_cowfp->if_seq);
314 xfs_iunlock(ip, XFS_ILOCK_SHARED);
316 whichfork = XFS_COW_FORK;
317 goto allocate_blocks;
321 * No COW extent overlap. Revalidate now that we may have updated
322 * ->cow_seq. If the data mapping is still valid, we're done.
324 if (xfs_imap_valid(wpc, ip, offset)) {
325 xfs_iunlock(ip, XFS_ILOCK_SHARED);
330 * If we don't have a valid map, now it's time to get a new one for this
331 * offset. This will convert delayed allocations (including COW ones)
334 if (!xfs_iext_lookup_extent(ip, &ip->i_df, offset_fsb, &icur, &imap))
335 imap.br_startoff = end_fsb; /* fake a hole past EOF */
336 XFS_WPC(wpc)->data_seq = READ_ONCE(ip->i_df.if_seq);
337 xfs_iunlock(ip, XFS_ILOCK_SHARED);
339 /* landed in a hole or beyond EOF? */
340 if (imap.br_startoff > offset_fsb) {
341 imap.br_blockcount = imap.br_startoff - offset_fsb;
342 imap.br_startoff = offset_fsb;
343 imap.br_startblock = HOLESTARTBLOCK;
344 imap.br_state = XFS_EXT_NORM;
348 * Truncate to the next COW extent if there is one. This is the only
349 * opportunity to do this because we can skip COW fork lookups for the
350 * subsequent blocks in the mapping; however, the requirement to treat
351 * the COW range separately remains.
353 if (cow_fsb != NULLFILEOFF &&
354 cow_fsb < imap.br_startoff + imap.br_blockcount)
355 imap.br_blockcount = cow_fsb - imap.br_startoff;
357 /* got a delalloc extent? */
358 if (imap.br_startblock != HOLESTARTBLOCK &&
359 isnullstartblock(imap.br_startblock))
360 goto allocate_blocks;
362 xfs_bmbt_to_iomap(ip, &wpc->iomap, &imap, 0, 0);
363 trace_xfs_map_blocks_found(ip, offset, count, whichfork, &imap);
366 error = xfs_convert_blocks(wpc, ip, whichfork, offset);
369 * If we failed to find the extent in the COW fork we might have
370 * raced with a COW to data fork conversion or truncate.
371 * Restart the lookup to catch the extent in the data fork for
372 * the former case, but prevent additional retries to avoid
373 * looping forever for the latter case.
375 if (error == -EAGAIN && whichfork == XFS_COW_FORK && !retries++)
377 ASSERT(error != -EAGAIN);
382 * Due to merging the return real extent might be larger than the
383 * original delalloc one. Trim the return extent to the next COW
384 * boundary again to force a re-lookup.
386 if (whichfork != XFS_COW_FORK && cow_fsb != NULLFILEOFF) {
387 loff_t cow_offset = XFS_FSB_TO_B(mp, cow_fsb);
389 if (cow_offset < wpc->iomap.offset + wpc->iomap.length)
390 wpc->iomap.length = cow_offset - wpc->iomap.offset;
393 ASSERT(wpc->iomap.offset <= offset);
394 ASSERT(wpc->iomap.offset + wpc->iomap.length > offset);
395 trace_xfs_map_blocks_alloc(ip, offset, count, whichfork, &imap);
401 struct iomap_ioend *ioend,
404 unsigned int nofs_flag;
407 * We can allocate memory here while doing writeback on behalf of
408 * memory reclaim. To avoid memory allocation deadlocks set the
409 * task-wide nofs context for the following operations.
411 nofs_flag = memalloc_nofs_save();
413 /* Convert CoW extents to regular */
414 if (!status && (ioend->io_flags & IOMAP_F_SHARED)) {
415 status = xfs_reflink_convert_cow(XFS_I(ioend->io_inode),
416 ioend->io_offset, ioend->io_size);
419 memalloc_nofs_restore(nofs_flag);
421 /* send ioends that might require a transaction to the completion wq */
422 if (xfs_ioend_is_append(ioend) || ioend->io_type == IOMAP_UNWRITTEN ||
423 (ioend->io_flags & IOMAP_F_SHARED))
424 ioend->io_bio->bi_end_io = xfs_end_bio;
429 * If the page has delalloc blocks on it, we need to punch them out before we
430 * invalidate the page. If we don't, we leave a stale delalloc mapping on the
431 * inode that can trip up a later direct I/O read operation on the same region.
433 * We prevent this by truncating away the delalloc regions on the page. Because
434 * they are delalloc, we can do this without needing a transaction. Indeed - if
435 * we get ENOSPC errors, we have to be able to do this truncation without a
436 * transaction as there is no space left for block reservation (typically why we
437 * see a ENOSPC in writeback).
444 struct inode *inode = folio->mapping->host;
445 struct xfs_inode *ip = XFS_I(inode);
446 struct xfs_mount *mp = ip->i_mount;
447 size_t offset = offset_in_folio(folio, pos);
448 xfs_fileoff_t start_fsb = XFS_B_TO_FSBT(mp, pos);
449 xfs_fileoff_t pageoff_fsb = XFS_B_TO_FSBT(mp, offset);
452 if (xfs_is_shutdown(mp))
455 xfs_alert_ratelimited(mp,
456 "page discard on page "PTR_FMT", inode 0x%llx, pos %llu.",
457 folio, ip->i_ino, pos);
459 error = xfs_bmap_punch_delalloc_range(ip, start_fsb,
460 i_blocks_per_folio(inode, folio) - pageoff_fsb);
461 if (error && !xfs_is_shutdown(mp))
462 xfs_alert(mp, "page discard unable to remove delalloc mapping.");
464 iomap_invalidate_folio(folio, offset, folio_size(folio) - offset);
467 static const struct iomap_writeback_ops xfs_writeback_ops = {
468 .map_blocks = xfs_map_blocks,
469 .prepare_ioend = xfs_prepare_ioend,
470 .discard_folio = xfs_discard_folio,
475 struct address_space *mapping,
476 struct writeback_control *wbc)
478 struct xfs_writepage_ctx wpc = { };
481 * Writing back data in a transaction context can result in recursive
482 * transactions. This is bad, so issue a warning and get out of here.
484 if (WARN_ON_ONCE(current->journal_info))
487 xfs_iflags_clear(XFS_I(mapping->host), XFS_ITRUNCATED);
488 return iomap_writepages(mapping, wbc, &wpc.ctx, &xfs_writeback_ops);
493 struct address_space *mapping,
494 struct writeback_control *wbc)
496 struct xfs_inode *ip = XFS_I(mapping->host);
498 xfs_iflags_clear(ip, XFS_ITRUNCATED);
499 return dax_writeback_mapping_range(mapping,
500 xfs_inode_buftarg(ip)->bt_daxdev, wbc);
505 struct address_space *mapping,
508 struct xfs_inode *ip = XFS_I(mapping->host);
510 trace_xfs_vm_bmap(ip);
513 * The swap code (ab-)uses ->bmap to get a block mapping and then
514 * bypasses the file system for actual I/O. We really can't allow
515 * that on reflinks inodes, so we have to skip out here. And yes,
516 * 0 is the magic code for a bmap error.
518 * Since we don't pass back blockdev info, we can't return bmap
519 * information for rt files either.
521 if (xfs_is_cow_inode(ip) || XFS_IS_REALTIME_INODE(ip))
523 return iomap_bmap(mapping, block, &xfs_read_iomap_ops);
531 return iomap_readpage(page, &xfs_read_iomap_ops);
536 struct readahead_control *rac)
538 iomap_readahead(rac, &xfs_read_iomap_ops);
542 xfs_iomap_swapfile_activate(
543 struct swap_info_struct *sis,
544 struct file *swap_file,
547 sis->bdev = xfs_inode_buftarg(XFS_I(file_inode(swap_file)))->bt_bdev;
548 return iomap_swapfile_activate(sis, swap_file, span,
549 &xfs_read_iomap_ops);
552 const struct address_space_operations xfs_address_space_operations = {
553 .readpage = xfs_vm_readpage,
554 .readahead = xfs_vm_readahead,
555 .writepages = xfs_vm_writepages,
556 .set_page_dirty = __set_page_dirty_nobuffers,
557 .releasepage = iomap_releasepage,
558 .invalidatepage = iomap_invalidatepage,
560 .direct_IO = noop_direct_IO,
561 .migratepage = iomap_migrate_page,
562 .is_partially_uptodate = iomap_is_partially_uptodate,
563 .error_remove_page = generic_error_remove_page,
564 .swap_activate = xfs_iomap_swapfile_activate,
567 const struct address_space_operations xfs_dax_aops = {
568 .writepages = xfs_dax_writepages,
569 .direct_IO = noop_direct_IO,
570 .set_page_dirty = __set_page_dirty_no_writeback,
571 .invalidatepage = noop_invalidatepage,
572 .swap_activate = xfs_iomap_swapfile_activate,