/* * Copyright (c) 2000-2005 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_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_trans.h" #include "xfs_inode_item.h" #include "xfs_alloc.h" #include "xfs_error.h" #include "xfs_iomap.h" #include "xfs_trace.h" #include "xfs_bmap.h" #include "xfs_bmap_util.h" #include "xfs_bmap_btree.h" #include #include #include #include void xfs_count_page_state( struct page *page, int *delalloc, int *unwritten) { struct buffer_head *bh, *head; *delalloc = *unwritten = 0; bh = head = page_buffers(page); do { if (buffer_unwritten(bh)) (*unwritten) = 1; else if (buffer_delay(bh)) (*delalloc) = 1; } while ((bh = bh->b_this_page) != head); } STATIC struct block_device * xfs_find_bdev_for_inode( struct inode *inode) { struct xfs_inode *ip = XFS_I(inode); struct xfs_mount *mp = ip->i_mount; if (XFS_IS_REALTIME_INODE(ip)) return mp->m_rtdev_targp->bt_bdev; else return mp->m_ddev_targp->bt_bdev; } /* * We're now finished for good with this ioend structure. * Update the page state via the associated buffer_heads, * release holds on the inode and bio, and finally free * up memory. Do not use the ioend after this. */ STATIC void xfs_destroy_ioend( xfs_ioend_t *ioend) { struct buffer_head *bh, *next; for (bh = ioend->io_buffer_head; bh; bh = next) { next = bh->b_private; bh->b_end_io(bh, !ioend->io_error); } mempool_free(ioend, xfs_ioend_pool); } /* * Fast and loose check if this write could update the on-disk inode size. */ static inline bool xfs_ioend_is_append(struct xfs_ioend *ioend) { return ioend->io_offset + ioend->io_size > XFS_I(ioend->io_inode)->i_d.di_size; } STATIC int xfs_setfilesize_trans_alloc( struct xfs_ioend *ioend) { struct xfs_mount *mp = XFS_I(ioend->io_inode)->i_mount; struct xfs_trans *tp; int error; tp = xfs_trans_alloc(mp, XFS_TRANS_FSYNC_TS); error = xfs_trans_reserve(tp, &M_RES(mp)->tr_fsyncts, 0, 0); if (error) { xfs_trans_cancel(tp, 0); return error; } ioend->io_append_trans = tp; /* * We may pass freeze protection with a transaction. So tell lockdep * we released it. */ rwsem_release(&ioend->io_inode->i_sb->s_writers.lock_map[SB_FREEZE_FS-1], 1, _THIS_IP_); /* * We hand off the transaction to the completion thread now, so * clear the flag here. */ current_restore_flags_nested(&tp->t_pflags, PF_FSTRANS); return 0; } /* * Update on-disk file size now that data has been written to disk. */ STATIC int xfs_setfilesize( struct xfs_inode *ip, struct xfs_trans *tp, xfs_off_t offset, size_t size) { xfs_fsize_t isize; xfs_ilock(ip, XFS_ILOCK_EXCL); isize = xfs_new_eof(ip, offset + size); if (!isize) { xfs_iunlock(ip, XFS_ILOCK_EXCL); xfs_trans_cancel(tp, 0); return 0; } trace_xfs_setfilesize(ip, offset, size); ip->i_d.di_size = isize; xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL); xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE); return xfs_trans_commit(tp, 0); } STATIC int xfs_setfilesize_ioend( struct xfs_ioend *ioend) { struct xfs_inode *ip = XFS_I(ioend->io_inode); struct xfs_trans *tp = ioend->io_append_trans; /* * The transaction may have been allocated in the I/O submission thread, * thus we need to mark ourselves as being in a transaction manually. * Similarly for freeze protection. */ current_set_flags_nested(&tp->t_pflags, PF_FSTRANS); rwsem_acquire_read(&VFS_I(ip)->i_sb->s_writers.lock_map[SB_FREEZE_FS-1], 0, 1, _THIS_IP_); return xfs_setfilesize(ip, tp, ioend->io_offset, ioend->io_size); } /* * Schedule IO completion handling on the final put of an ioend. * * If there is no work to do we might as well call it a day and free the * ioend right now. */ STATIC void xfs_finish_ioend( struct xfs_ioend *ioend) { if (atomic_dec_and_test(&ioend->io_remaining)) { struct xfs_mount *mp = XFS_I(ioend->io_inode)->i_mount; if (ioend->io_type == XFS_IO_UNWRITTEN) queue_work(mp->m_unwritten_workqueue, &ioend->io_work); else if (ioend->io_append_trans) queue_work(mp->m_data_workqueue, &ioend->io_work); else xfs_destroy_ioend(ioend); } } /* * IO write completion. */ STATIC void xfs_end_io( struct work_struct *work) { xfs_ioend_t *ioend = container_of(work, xfs_ioend_t, io_work); struct xfs_inode *ip = XFS_I(ioend->io_inode); int error = 0; if (XFS_FORCED_SHUTDOWN(ip->i_mount)) { ioend->io_error = -EIO; goto done; } if (ioend->io_error) goto done; /* * For unwritten extents we need to issue transactions to convert a * range to normal written extens after the data I/O has finished. */ if (ioend->io_type == XFS_IO_UNWRITTEN) { error = xfs_iomap_write_unwritten(ip, ioend->io_offset, ioend->io_size); } else if (ioend->io_append_trans) { error = xfs_setfilesize_ioend(ioend); } else { ASSERT(!xfs_ioend_is_append(ioend)); } done: if (error) ioend->io_error = error; xfs_destroy_ioend(ioend); } /* * Allocate and initialise an IO completion structure. * We need to track unwritten extent write completion here initially. * We'll need to extend this for updating the ondisk inode size later * (vs. incore size). */ STATIC xfs_ioend_t * xfs_alloc_ioend( struct inode *inode, unsigned int type) { xfs_ioend_t *ioend; ioend = mempool_alloc(xfs_ioend_pool, GFP_NOFS); /* * Set the count to 1 initially, which will prevent an I/O * completion callback from happening before we have started * all the I/O from calling the completion routine too early. */ atomic_set(&ioend->io_remaining, 1); ioend->io_error = 0; ioend->io_list = NULL; ioend->io_type = type; ioend->io_inode = inode; ioend->io_buffer_head = NULL; ioend->io_buffer_tail = NULL; ioend->io_offset = 0; ioend->io_size = 0; ioend->io_append_trans = NULL; INIT_WORK(&ioend->io_work, xfs_end_io); return ioend; } STATIC int xfs_map_blocks( struct inode *inode, loff_t offset, struct xfs_bmbt_irec *imap, int type, int nonblocking) { struct xfs_inode *ip = XFS_I(inode); struct xfs_mount *mp = ip->i_mount; ssize_t count = 1 << inode->i_blkbits; xfs_fileoff_t offset_fsb, end_fsb; int error = 0; int bmapi_flags = XFS_BMAPI_ENTIRE; int nimaps = 1; if (XFS_FORCED_SHUTDOWN(mp)) return -EIO; if (type == XFS_IO_UNWRITTEN) bmapi_flags |= XFS_BMAPI_IGSTATE; if (!xfs_ilock_nowait(ip, XFS_ILOCK_SHARED)) { if (nonblocking) return -EAGAIN; xfs_ilock(ip, XFS_ILOCK_SHARED); } ASSERT(ip->i_d.di_format != XFS_DINODE_FMT_BTREE || (ip->i_df.if_flags & XFS_IFEXTENTS)); ASSERT(offset <= mp->m_super->s_maxbytes); if (offset + count > mp->m_super->s_maxbytes) count = mp->m_super->s_maxbytes - offset; end_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)offset + count); offset_fsb = XFS_B_TO_FSBT(mp, offset); error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb, imap, &nimaps, bmapi_flags); xfs_iunlock(ip, XFS_ILOCK_SHARED); if (error) return error; if (type == XFS_IO_DELALLOC && (!nimaps || isnullstartblock(imap->br_startblock))) { error = xfs_iomap_write_allocate(ip, offset, imap); if (!error) trace_xfs_map_blocks_alloc(ip, offset, count, type, imap); return error; } #ifdef DEBUG if (type == XFS_IO_UNWRITTEN) { ASSERT(nimaps); ASSERT(imap->br_startblock != HOLESTARTBLOCK); ASSERT(imap->br_startblock != DELAYSTARTBLOCK); } #endif if (nimaps) trace_xfs_map_blocks_found(ip, offset, count, type, imap); return 0; } STATIC int xfs_imap_valid( struct inode *inode, struct xfs_bmbt_irec *imap, xfs_off_t offset) { offset >>= inode->i_blkbits; return offset >= imap->br_startoff && offset < imap->br_startoff + imap->br_blockcount; } /* * BIO completion handler for buffered IO. */ STATIC void xfs_end_bio( struct bio *bio, int error) { xfs_ioend_t *ioend = bio->bi_private; ASSERT(atomic_read(&bio->bi_cnt) >= 1); ioend->io_error = test_bit(BIO_UPTODATE, &bio->bi_flags) ? 0 : error; /* Toss bio and pass work off to an xfsdatad thread */ bio->bi_private = NULL; bio->bi_end_io = NULL; bio_put(bio); xfs_finish_ioend(ioend); } STATIC void xfs_submit_ioend_bio( struct writeback_control *wbc, xfs_ioend_t *ioend, struct bio *bio) { atomic_inc(&ioend->io_remaining); bio->bi_private = ioend; bio->bi_end_io = xfs_end_bio; submit_bio(wbc->sync_mode == WB_SYNC_ALL ? WRITE_SYNC : WRITE, bio); } STATIC struct bio * xfs_alloc_ioend_bio( struct buffer_head *bh) { int nvecs = bio_get_nr_vecs(bh->b_bdev); struct bio *bio = bio_alloc(GFP_NOIO, nvecs); ASSERT(bio->bi_private == NULL); bio->bi_iter.bi_sector = bh->b_blocknr * (bh->b_size >> 9); bio->bi_bdev = bh->b_bdev; return bio; } STATIC void xfs_start_buffer_writeback( struct buffer_head *bh) { ASSERT(buffer_mapped(bh)); ASSERT(buffer_locked(bh)); ASSERT(!buffer_delay(bh)); ASSERT(!buffer_unwritten(bh)); mark_buffer_async_write(bh); set_buffer_uptodate(bh); clear_buffer_dirty(bh); } STATIC void xfs_start_page_writeback( struct page *page, int clear_dirty, int buffers) { ASSERT(PageLocked(page)); ASSERT(!PageWriteback(page)); /* * if the page was not fully cleaned, we need to ensure that the higher * layers come back to it correctly. That means we need to keep the page * dirty, and for WB_SYNC_ALL writeback we need to ensure the * PAGECACHE_TAG_TOWRITE index mark is not removed so another attempt to * write this page in this writeback sweep will be made. */ if (clear_dirty) { clear_page_dirty_for_io(page); set_page_writeback(page); } else set_page_writeback_keepwrite(page); unlock_page(page); /* If no buffers on the page are to be written, finish it here */ if (!buffers) end_page_writeback(page); } static inline int xfs_bio_add_buffer(struct bio *bio, struct buffer_head *bh) { return bio_add_page(bio, bh->b_page, bh->b_size, bh_offset(bh)); } /* * Submit all of the bios for all of the ioends we have saved up, covering the * initial writepage page and also any probed pages. * * Because we may have multiple ioends spanning a page, we need to start * writeback on all the buffers before we submit them for I/O. If we mark the * buffers as we got, then we can end up with a page that only has buffers * marked async write and I/O complete on can occur before we mark the other * buffers async write. * * The end result of this is that we trip a bug in end_page_writeback() because * we call it twice for the one page as the code in end_buffer_async_write() * assumes that all buffers on the page are started at the same time. * * The fix is two passes across the ioend list - one to start writeback on the * buffer_heads, and then submit them for I/O on the second pass. * * If @fail is non-zero, it means that we have a situation where some part of * the submission process has failed after we have marked paged for writeback * and unlocked them. In this situation, we need to fail the ioend chain rather * than submit it to IO. This typically only happens on a filesystem shutdown. */ STATIC void xfs_submit_ioend( struct writeback_control *wbc, xfs_ioend_t *ioend, int fail) { xfs_ioend_t *head = ioend; xfs_ioend_t *next; struct buffer_head *bh; struct bio *bio; sector_t lastblock = 0; /* Pass 1 - start writeback */ do { next = ioend->io_list; for (bh = ioend->io_buffer_head; bh; bh = bh->b_private) xfs_start_buffer_writeback(bh); } while ((ioend = next) != NULL); /* Pass 2 - submit I/O */ ioend = head; do { next = ioend->io_list; bio = NULL; /* * If we are failing the IO now, just mark the ioend with an * error and finish it. This will run IO completion immediately * as there is only one reference to the ioend at this point in * time. */ if (fail) { ioend->io_error = fail; xfs_finish_ioend(ioend); continue; } for (bh = ioend->io_buffer_head; bh; bh = bh->b_private) { if (!bio) { retry: bio = xfs_alloc_ioend_bio(bh); } else if (bh->b_blocknr != lastblock + 1) { xfs_submit_ioend_bio(wbc, ioend, bio); goto retry; } if (xfs_bio_add_buffer(bio, bh) != bh->b_size) { xfs_submit_ioend_bio(wbc, ioend, bio); goto retry; } lastblock = bh->b_blocknr; } if (bio) xfs_submit_ioend_bio(wbc, ioend, bio); xfs_finish_ioend(ioend); } while ((ioend = next) != NULL); } /* * Cancel submission of all buffer_heads so far in this endio. * Toss the endio too. Only ever called for the initial page * in a writepage request, so only ever one page. */ STATIC void xfs_cancel_ioend( xfs_ioend_t *ioend) { xfs_ioend_t *next; struct buffer_head *bh, *next_bh; do { next = ioend->io_list; bh = ioend->io_buffer_head; do { next_bh = bh->b_private; clear_buffer_async_write(bh); /* * The unwritten flag is cleared when added to the * ioend. We're not submitting for I/O so mark the * buffer unwritten again for next time around. */ if (ioend->io_type == XFS_IO_UNWRITTEN) set_buffer_unwritten(bh); unlock_buffer(bh); } while ((bh = next_bh) != NULL); mempool_free(ioend, xfs_ioend_pool); } while ((ioend = next) != NULL); } /* * Test to see if we've been building up a completion structure for * earlier buffers -- if so, we try to append to this ioend if we * can, otherwise we finish off any current ioend and start another. * Return true if we've finished the given ioend. */ STATIC void xfs_add_to_ioend( struct inode *inode, struct buffer_head *bh, xfs_off_t offset, unsigned int type, xfs_ioend_t **result, int need_ioend) { xfs_ioend_t *ioend = *result; if (!ioend || need_ioend || type != ioend->io_type) { xfs_ioend_t *previous = *result; ioend = xfs_alloc_ioend(inode, type); ioend->io_offset = offset; ioend->io_buffer_head = bh; ioend->io_buffer_tail = bh; if (previous) previous->io_list = ioend; *result = ioend; } else { ioend->io_buffer_tail->b_private = bh; ioend->io_buffer_tail = bh; } bh->b_private = NULL; ioend->io_size += bh->b_size; } STATIC void xfs_map_buffer( struct inode *inode, struct buffer_head *bh, struct xfs_bmbt_irec *imap, xfs_off_t offset) { sector_t bn; struct xfs_mount *m = XFS_I(inode)->i_mount; xfs_off_t iomap_offset = XFS_FSB_TO_B(m, imap->br_startoff); xfs_daddr_t iomap_bn = xfs_fsb_to_db(XFS_I(inode), imap->br_startblock); ASSERT(imap->br_startblock != HOLESTARTBLOCK); ASSERT(imap->br_startblock != DELAYSTARTBLOCK); bn = (iomap_bn >> (inode->i_blkbits - BBSHIFT)) + ((offset - iomap_offset) >> inode->i_blkbits); ASSERT(bn || XFS_IS_REALTIME_INODE(XFS_I(inode))); bh->b_blocknr = bn; set_buffer_mapped(bh); } STATIC void xfs_map_at_offset( struct inode *inode, struct buffer_head *bh, struct xfs_bmbt_irec *imap, xfs_off_t offset) { ASSERT(imap->br_startblock != HOLESTARTBLOCK); ASSERT(imap->br_startblock != DELAYSTARTBLOCK); xfs_map_buffer(inode, bh, imap, offset); set_buffer_mapped(bh); clear_buffer_delay(bh); clear_buffer_unwritten(bh); } /* * Test if a given page contains at least one buffer of a given @type. * If @check_all_buffers is true, then we walk all the buffers in the page to * try to find one of the type passed in. If it is not set, then the caller only * needs to check the first buffer on the page for a match. */ STATIC bool xfs_check_page_type( struct page *page, unsigned int type, bool check_all_buffers) { struct buffer_head *bh; struct buffer_head *head; if (PageWriteback(page)) return false; if (!page->mapping) return false; if (!page_has_buffers(page)) return false; bh = head = page_buffers(page); do { if (buffer_unwritten(bh)) { if (type == XFS_IO_UNWRITTEN) return true; } else if (buffer_delay(bh)) { if (type == XFS_IO_DELALLOC) return true; } else if (buffer_dirty(bh) && buffer_mapped(bh)) { if (type == XFS_IO_OVERWRITE) return true; } /* If we are only checking the first buffer, we are done now. */ if (!check_all_buffers) break; } while ((bh = bh->b_this_page) != head); return false; } /* * Allocate & map buffers for page given the extent map. Write it out. * except for the original page of a writepage, this is called on * delalloc/unwritten pages only, for the original page it is possible * that the page has no mapping at all. */ STATIC int xfs_convert_page( struct inode *inode, struct page *page, loff_t tindex, struct xfs_bmbt_irec *imap, xfs_ioend_t **ioendp, struct writeback_control *wbc) { struct buffer_head *bh, *head; xfs_off_t end_offset; unsigned long p_offset; unsigned int type; int len, page_dirty; int count = 0, done = 0, uptodate = 1; xfs_off_t offset = page_offset(page); if (page->index != tindex) goto fail; if (!trylock_page(page)) goto fail; if (PageWriteback(page)) goto fail_unlock_page; if (page->mapping != inode->i_mapping) goto fail_unlock_page; if (!xfs_check_page_type(page, (*ioendp)->io_type, false)) goto fail_unlock_page; /* * page_dirty is initially a count of buffers on the page before * EOF and is decremented as we move each into a cleanable state. * * Derivation: * * End offset is the highest offset that this page should represent. * If we are on the last page, (end_offset & (PAGE_CACHE_SIZE - 1)) * will evaluate non-zero and be less than PAGE_CACHE_SIZE and * hence give us the correct page_dirty count. On any other page, * it will be zero and in that case we need page_dirty to be the * count of buffers on the page. */ end_offset = min_t(unsigned long long, (xfs_off_t)(page->index + 1) << PAGE_CACHE_SHIFT, i_size_read(inode)); /* * If the current map does not span the entire page we are about to try * to write, then give up. The only way we can write a page that spans * multiple mappings in a single writeback iteration is via the * xfs_vm_writepage() function. Data integrity writeback requires the * entire page to be written in a single attempt, otherwise the part of * the page we don't write here doesn't get written as part of the data * integrity sync. * * For normal writeback, we also don't attempt to write partial pages * here as it simply means that write_cache_pages() will see it under * writeback and ignore the page until some point in the future, at * which time this will be the only page in the file that needs * writeback. Hence for more optimal IO patterns, we should always * avoid partial page writeback due to multiple mappings on a page here. */ if (!xfs_imap_valid(inode, imap, end_offset)) goto fail_unlock_page; len = 1 << inode->i_blkbits; p_offset = min_t(unsigned long, end_offset & (PAGE_CACHE_SIZE - 1), PAGE_CACHE_SIZE); p_offset = p_offset ? roundup(p_offset, len) : PAGE_CACHE_SIZE; page_dirty = p_offset / len; /* * The moment we find a buffer that doesn't match our current type * specification or can't be written, abort the loop and start * writeback. As per the above xfs_imap_valid() check, only * xfs_vm_writepage() can handle partial page writeback fully - we are * limited here to the buffers that are contiguous with the current * ioend, and hence a buffer we can't write breaks that contiguity and * we have to defer the rest of the IO to xfs_vm_writepage(). */ bh = head = page_buffers(page); do { if (offset >= end_offset) break; if (!buffer_uptodate(bh)) uptodate = 0; if (!(PageUptodate(page) || buffer_uptodate(bh))) { done = 1; break; } if (buffer_unwritten(bh) || buffer_delay(bh) || buffer_mapped(bh)) { if (buffer_unwritten(bh)) type = XFS_IO_UNWRITTEN; else if (buffer_delay(bh)) type = XFS_IO_DELALLOC; else type = XFS_IO_OVERWRITE; /* * imap should always be valid because of the above * partial page end_offset check on the imap. */ ASSERT(xfs_imap_valid(inode, imap, offset)); lock_buffer(bh); if (type != XFS_IO_OVERWRITE) xfs_map_at_offset(inode, bh, imap, offset); xfs_add_to_ioend(inode, bh, offset, type, ioendp, done); page_dirty--; count++; } else { done = 1; break; } } while (offset += len, (bh = bh->b_this_page) != head); if (uptodate && bh == head) SetPageUptodate(page); if (count) { if (--wbc->nr_to_write <= 0 && wbc->sync_mode == WB_SYNC_NONE) done = 1; } xfs_start_page_writeback(page, !page_dirty, count); return done; fail_unlock_page: unlock_page(page); fail: return 1; } /* * Convert & write out a cluster of pages in the same extent as defined * by mp and following the start page. */ STATIC void xfs_cluster_write( struct inode *inode, pgoff_t tindex, struct xfs_bmbt_irec *imap, xfs_ioend_t **ioendp, struct writeback_control *wbc, pgoff_t tlast) { struct pagevec pvec; int done = 0, i; pagevec_init(&pvec, 0); while (!done && tindex <= tlast) { unsigned len = min_t(pgoff_t, PAGEVEC_SIZE, tlast - tindex + 1); if (!pagevec_lookup(&pvec, inode->i_mapping, tindex, len)) break; for (i = 0; i < pagevec_count(&pvec); i++) { done = xfs_convert_page(inode, pvec.pages[i], tindex++, imap, ioendp, wbc); if (done) break; } pagevec_release(&pvec); cond_resched(); } } STATIC void xfs_vm_invalidatepage( struct page *page, unsigned int offset, unsigned int length) { trace_xfs_invalidatepage(page->mapping->host, page, offset, length); block_invalidatepage(page, offset, length); } /* * If the page has delalloc buffers on it, we need to punch them out before we * invalidate the page. If we don't, we leave a stale delalloc mapping on the * inode that can trip a BUG() in xfs_get_blocks() later on if a direct IO read * is done on that same region - the delalloc extent is returned when none is * supposed to be there. * * We prevent this by truncating away the delalloc regions on the page before * invalidating it. Because they are delalloc, we can do this without needing a * transaction. Indeed - if we get ENOSPC errors, we have to be able to do this * truncation without a transaction as there is no space left for block * reservation (typically why we see a ENOSPC in writeback). * * This is not a performance critical path, so for now just do the punching a * buffer head at a time. */ STATIC void xfs_aops_discard_page( struct page *page) { struct inode *inode = page->mapping->host; struct xfs_inode *ip = XFS_I(inode); struct buffer_head *bh, *head; loff_t offset = page_offset(page); if (!xfs_check_page_type(page, XFS_IO_DELALLOC, true)) goto out_invalidate; if (XFS_FORCED_SHUTDOWN(ip->i_mount)) goto out_invalidate; xfs_alert(ip->i_mount, "page discard on page %p, inode 0x%llx, offset %llu.", page, ip->i_ino, offset); xfs_ilock(ip, XFS_ILOCK_EXCL); bh = head = page_buffers(page); do { int error; xfs_fileoff_t start_fsb; if (!buffer_delay(bh)) goto next_buffer; start_fsb = XFS_B_TO_FSBT(ip->i_mount, offset); error = xfs_bmap_punch_delalloc_range(ip, start_fsb, 1); if (error) { /* something screwed, just bail */ if (!XFS_FORCED_SHUTDOWN(ip->i_mount)) { xfs_alert(ip->i_mount, "page discard unable to remove delalloc mapping."); } break; } next_buffer: offset += 1 << inode->i_blkbits; } while ((bh = bh->b_this_page) != head); xfs_iunlock(ip, XFS_ILOCK_EXCL); out_invalidate: xfs_vm_invalidatepage(page, 0, PAGE_CACHE_SIZE); return; } /* * Write out a dirty page. * * For delalloc space on the page we need to allocate space and flush it. * For unwritten space on the page we need to start the conversion to * regular allocated space. * For any other dirty buffer heads on the page we should flush them. */ STATIC int xfs_vm_writepage( struct page *page, struct writeback_control *wbc) { struct inode *inode = page->mapping->host; struct buffer_head *bh, *head; struct xfs_bmbt_irec imap; xfs_ioend_t *ioend = NULL, *iohead = NULL; loff_t offset; unsigned int type; __uint64_t end_offset; pgoff_t end_index, last_index; ssize_t len; int err, imap_valid = 0, uptodate = 1; int count = 0; int nonblocking = 0; trace_xfs_writepage(inode, page, 0, 0); ASSERT(page_has_buffers(page)); /* * Refuse to write the page out if we are called from reclaim context. * * This avoids stack overflows when called from deeply used stacks in * random callers for direct reclaim or memcg reclaim. We explicitly * allow reclaim from kswapd as the stack usage there is relatively low. * * This should never happen except in the case of a VM regression so * warn about it. */ if (WARN_ON_ONCE((current->flags & (PF_MEMALLOC|PF_KSWAPD)) == PF_MEMALLOC)) goto redirty; /* * Given that we do not allow direct reclaim to call us, we should * never be called while in a filesystem transaction. */ if (WARN_ON_ONCE(current->flags & PF_FSTRANS)) goto redirty; /* Is this page beyond the end of the file? */ offset = i_size_read(inode); end_index = offset >> PAGE_CACHE_SHIFT; last_index = (offset - 1) >> PAGE_CACHE_SHIFT; /* * The page index is less than the end_index, adjust the end_offset * to the highest offset that this page should represent. * ----------------------------------------------------- * | file mapping | | * ----------------------------------------------------- * | Page ... | Page N-2 | Page N-1 | Page N | | * ^--------------------------------^----------|-------- * | desired writeback range | see else | * ---------------------------------^------------------| */ if (page->index < end_index) end_offset = (xfs_off_t)(page->index + 1) << PAGE_CACHE_SHIFT; else { /* * Check whether the page to write out is beyond or straddles * i_size or not. * ------------------------------------------------------- * | file mapping | | * ------------------------------------------------------- * | Page ... | Page N-2 | Page N-1 | Page N | Beyond | * ^--------------------------------^-----------|--------- * | | Straddles | * ---------------------------------^-----------|--------| */ unsigned offset_into_page = offset & (PAGE_CACHE_SIZE - 1); /* * Skip the page if it is fully outside i_size, e.g. due to a * truncate operation that is in progress. We must redirty the * page so that reclaim stops reclaiming it. Otherwise * xfs_vm_releasepage() is called on it and gets confused. * * Note that the end_index is unsigned long, it would overflow * if the given offset is greater than 16TB on 32-bit system * and if we do check the page is fully outside i_size or not * via "if (page->index >= end_index + 1)" as "end_index + 1" * will be evaluated to 0. Hence this page will be redirtied * and be written out repeatedly which would result in an * infinite loop, the user program that perform this operation * will hang. Instead, we can verify this situation by checking * if the page to write is totally beyond the i_size or if it's * offset is just equal to the EOF. */ if (page->index > end_index || (page->index == end_index && offset_into_page == 0)) goto redirty; /* * The page straddles i_size. It must be zeroed out on each * and every writepage invocation because it may be mmapped. * "A file is mapped in multiples of the page size. For a file * that is not a multiple of the page size, the remaining * memory is zeroed when mapped, and writes to that region are * not written out to the file." */ zero_user_segment(page, offset_into_page, PAGE_CACHE_SIZE); /* Adjust the end_offset to the end of file */ end_offset = offset; } len = 1 << inode->i_blkbits; bh = head = page_buffers(page); offset = page_offset(page); type = XFS_IO_OVERWRITE; if (wbc->sync_mode == WB_SYNC_NONE) nonblocking = 1; do { int new_ioend = 0; if (offset >= end_offset) break; if (!buffer_uptodate(bh)) uptodate = 0; /* * set_page_dirty dirties all buffers in a page, independent * of their state. The dirty state however is entirely * meaningless for holes (!mapped && uptodate), so skip * buffers covering holes here. */ if (!buffer_mapped(bh) && buffer_uptodate(bh)) { imap_valid = 0; continue; } if (buffer_unwritten(bh)) { if (type != XFS_IO_UNWRITTEN) { type = XFS_IO_UNWRITTEN; imap_valid = 0; } } else if (buffer_delay(bh)) { if (type != XFS_IO_DELALLOC) { type = XFS_IO_DELALLOC; imap_valid = 0; } } else if (buffer_uptodate(bh)) { if (type != XFS_IO_OVERWRITE) { type = XFS_IO_OVERWRITE; imap_valid = 0; } } else { if (PageUptodate(page)) ASSERT(buffer_mapped(bh)); /* * This buffer is not uptodate and will not be * written to disk. Ensure that we will put any * subsequent writeable buffers into a new * ioend. */ imap_valid = 0; continue; } if (imap_valid) imap_valid = xfs_imap_valid(inode, &imap, offset); if (!imap_valid) { /* * If we didn't have a valid mapping then we need to * put the new mapping into a separate ioend structure. * This ensures non-contiguous extents always have * separate ioends, which is particularly important * for unwritten extent conversion at I/O completion * time. */ new_ioend = 1; err = xfs_map_blocks(inode, offset, &imap, type, nonblocking); if (err) goto error; imap_valid = xfs_imap_valid(inode, &imap, offset); } if (imap_valid) { lock_buffer(bh); if (type != XFS_IO_OVERWRITE) xfs_map_at_offset(inode, bh, &imap, offset); xfs_add_to_ioend(inode, bh, offset, type, &ioend, new_ioend); count++; } if (!iohead) iohead = ioend; } while (offset += len, ((bh = bh->b_this_page) != head)); if (uptodate && bh == head) SetPageUptodate(page); xfs_start_page_writeback(page, 1, count); /* if there is no IO to be submitted for this page, we are done */ if (!ioend) return 0; ASSERT(iohead); /* * Any errors from this point onwards need tobe reported through the IO * completion path as we have marked the initial page as under writeback * and unlocked it. */ if (imap_valid) { xfs_off_t end_index; end_index = imap.br_startoff + imap.br_blockcount; /* to bytes */ end_index <<= inode->i_blkbits; /* to pages */ end_index = (end_index - 1) >> PAGE_CACHE_SHIFT; /* check against file size */ if (end_index > last_index) end_index = last_index; xfs_cluster_write(inode, page->index + 1, &imap, &ioend, wbc, end_index); } /* * Reserve log space if we might write beyond the on-disk inode size. */ err = 0; if (ioend->io_type != XFS_IO_UNWRITTEN && xfs_ioend_is_append(ioend)) err = xfs_setfilesize_trans_alloc(ioend); xfs_submit_ioend(wbc, iohead, err); return 0; error: if (iohead) xfs_cancel_ioend(iohead); if (err == -EAGAIN) goto redirty; xfs_aops_discard_page(page); ClearPageUptodate(page); unlock_page(page); return err; redirty: redirty_page_for_writepage(wbc, page); unlock_page(page); return 0; } STATIC int xfs_vm_writepages( struct address_space *mapping, struct writeback_control *wbc) { xfs_iflags_clear(XFS_I(mapping->host), XFS_ITRUNCATED); return generic_writepages(mapping, wbc); } /* * Called to move a page into cleanable state - and from there * to be released. The page should already be clean. We always * have buffer heads in this call. * * Returns 1 if the page is ok to release, 0 otherwise. */ STATIC int xfs_vm_releasepage( struct page *page, gfp_t gfp_mask) { int delalloc, unwritten; trace_xfs_releasepage(page->mapping->host, page, 0, 0); xfs_count_page_state(page, &delalloc, &unwritten); if (WARN_ON_ONCE(delalloc)) return 0; if (WARN_ON_ONCE(unwritten)) return 0; return try_to_free_buffers(page); } /* * When we map a DIO buffer, we may need to attach an ioend that describes the * type of write IO we are doing. This passes to the completion function the * operations it needs to perform. If the mapping is for an overwrite wholly * within the EOF then we don't need an ioend and so we don't allocate one. * This avoids the unnecessary overhead of allocating and freeing ioends for * workloads that don't require transactions on IO completion. * * If we get multiple mappings in a single IO, we might be mapping different * types. But because the direct IO can only have a single private pointer, we * need to ensure that: * * a) i) the ioend spans the entire region of unwritten mappings; or * ii) the ioend spans all the mappings that cross or are beyond EOF; and * b) if it contains unwritten extents, it is *permanently* marked as such * * We could do this by chaining ioends like buffered IO does, but we only * actually get one IO completion callback from the direct IO, and that spans * the entire IO regardless of how many mappings and IOs are needed to complete * the DIO. There is only going to be one reference to the ioend and its life * cycle is constrained by the DIO completion code. hence we don't need * reference counting here. */ static void xfs_map_direct( struct inode *inode, struct buffer_head *bh_result, struct xfs_bmbt_irec *imap, xfs_off_t offset) { struct xfs_ioend *ioend; xfs_off_t size = bh_result->b_size; int type; if (ISUNWRITTEN(imap)) type = XFS_IO_UNWRITTEN; else type = XFS_IO_OVERWRITE; trace_xfs_gbmap_direct(XFS_I(inode), offset, size, type, imap); if (bh_result->b_private) { ioend = bh_result->b_private; ASSERT(ioend->io_size > 0); ASSERT(offset >= ioend->io_offset); if (offset + size > ioend->io_offset + ioend->io_size) ioend->io_size = offset - ioend->io_offset + size; if (type == XFS_IO_UNWRITTEN && type != ioend->io_type) ioend->io_type = XFS_IO_UNWRITTEN; trace_xfs_gbmap_direct_update(XFS_I(inode), ioend->io_offset, ioend->io_size, ioend->io_type, imap); } else if (type == XFS_IO_UNWRITTEN || offset + size > i_size_read(inode)) { ioend = xfs_alloc_ioend(inode, type); ioend->io_offset = offset; ioend->io_size = size; bh_result->b_private = ioend; set_buffer_defer_completion(bh_result); trace_xfs_gbmap_direct_new(XFS_I(inode), offset, size, type, imap); } else { trace_xfs_gbmap_direct_none(XFS_I(inode), offset, size, type, imap); } } /* * If this is O_DIRECT or the mpage code calling tell them how large the mapping * is, so that we can avoid repeated get_blocks calls. * * If the mapping spans EOF, then we have to break the mapping up as the mapping * for blocks beyond EOF must be marked new so that sub block regions can be * correctly zeroed. We can't do this for mappings within EOF unless the mapping * was just allocated or is unwritten, otherwise the callers would overwrite * existing data with zeros. Hence we have to split the mapping into a range up * to and including EOF, and a second mapping for beyond EOF. */ static void xfs_map_trim_size( struct inode *inode, sector_t iblock, struct buffer_head *bh_result, struct xfs_bmbt_irec *imap, xfs_off_t offset, ssize_t size) { xfs_off_t mapping_size; mapping_size = imap->br_startoff + imap->br_blockcount - iblock; mapping_size <<= inode->i_blkbits; ASSERT(mapping_size > 0); if (mapping_size > size) mapping_size = size; if (offset < i_size_read(inode) && offset + mapping_size >= i_size_read(inode)) { /* limit mapping to block that spans EOF */ mapping_size = roundup_64(i_size_read(inode) - offset, 1 << inode->i_blkbits); } if (mapping_size > LONG_MAX) mapping_size = LONG_MAX; bh_result->b_size = mapping_size; } STATIC int __xfs_get_blocks( struct inode *inode, sector_t iblock, struct buffer_head *bh_result, int create, bool direct) { struct xfs_inode *ip = XFS_I(inode); struct xfs_mount *mp = ip->i_mount; xfs_fileoff_t offset_fsb, end_fsb; int error = 0; int lockmode = 0; struct xfs_bmbt_irec imap; int nimaps = 1; xfs_off_t offset; ssize_t size; int new = 0; if (XFS_FORCED_SHUTDOWN(mp)) return -EIO; offset = (xfs_off_t)iblock << inode->i_blkbits; ASSERT(bh_result->b_size >= (1 << inode->i_blkbits)); size = bh_result->b_size; if (!create && direct && offset >= i_size_read(inode)) return 0; /* * Direct I/O is usually done on preallocated files, so try getting * a block mapping without an exclusive lock first. For buffered * writes we already have the exclusive iolock anyway, so avoiding * a lock roundtrip here by taking the ilock exclusive from the * beginning is a useful micro optimization. */ if (create && !direct) { lockmode = XFS_ILOCK_EXCL; xfs_ilock(ip, lockmode); } else { lockmode = xfs_ilock_data_map_shared(ip); } ASSERT(offset <= mp->m_super->s_maxbytes); if (offset + size > mp->m_super->s_maxbytes) size = mp->m_super->s_maxbytes - offset; end_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)offset + size); offset_fsb = XFS_B_TO_FSBT(mp, offset); error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb, &imap, &nimaps, XFS_BMAPI_ENTIRE); if (error) goto out_unlock; if (create && (!nimaps || (imap.br_startblock == HOLESTARTBLOCK || imap.br_startblock == DELAYSTARTBLOCK))) { if (direct || xfs_get_extsz_hint(ip)) { /* * Drop the ilock in preparation for starting the block * allocation transaction. It will be retaken * exclusively inside xfs_iomap_write_direct for the * actual allocation. */ xfs_iunlock(ip, lockmode); error = xfs_iomap_write_direct(ip, offset, size, &imap, nimaps); if (error) return error; new = 1; } else { /* * Delalloc reservations do not require a transaction, * we can go on without dropping the lock here. If we * are allocating a new delalloc block, make sure that * we set the new flag so that we mark the buffer new so * that we know that it is newly allocated if the write * fails. */ if (nimaps && imap.br_startblock == HOLESTARTBLOCK) new = 1; error = xfs_iomap_write_delay(ip, offset, size, &imap); if (error) goto out_unlock; xfs_iunlock(ip, lockmode); } trace_xfs_get_blocks_alloc(ip, offset, size, ISUNWRITTEN(&imap) ? XFS_IO_UNWRITTEN : XFS_IO_DELALLOC, &imap); } else if (nimaps) { trace_xfs_get_blocks_found(ip, offset, size, ISUNWRITTEN(&imap) ? XFS_IO_UNWRITTEN : XFS_IO_OVERWRITE, &imap); xfs_iunlock(ip, lockmode); } else { trace_xfs_get_blocks_notfound(ip, offset, size); goto out_unlock; } /* trim mapping down to size requested */ if (direct || size > (1 << inode->i_blkbits)) xfs_map_trim_size(inode, iblock, bh_result, &imap, offset, size); /* * For unwritten extents do not report a disk address in the buffered * read case (treat as if we're reading into a hole). */ if (imap.br_startblock != HOLESTARTBLOCK && imap.br_startblock != DELAYSTARTBLOCK && (create || !ISUNWRITTEN(&imap))) { xfs_map_buffer(inode, bh_result, &imap, offset); if (ISUNWRITTEN(&imap)) set_buffer_unwritten(bh_result); /* direct IO needs special help */ if (create && direct) xfs_map_direct(inode, bh_result, &imap, offset); } /* * If this is a realtime file, data may be on a different device. * to that pointed to from the buffer_head b_bdev currently. */ bh_result->b_bdev = xfs_find_bdev_for_inode(inode); /* * If we previously allocated a block out beyond eof and we are now * coming back to use it then we will need to flag it as new even if it * has a disk address. * * With sub-block writes into unwritten extents we also need to mark * the buffer as new so that the unwritten parts of the buffer gets * correctly zeroed. */ if (create && ((!buffer_mapped(bh_result) && !buffer_uptodate(bh_result)) || (offset >= i_size_read(inode)) || (new || ISUNWRITTEN(&imap)))) set_buffer_new(bh_result); if (imap.br_startblock == DELAYSTARTBLOCK) { BUG_ON(direct); if (create) { set_buffer_uptodate(bh_result); set_buffer_mapped(bh_result); set_buffer_delay(bh_result); } } return 0; out_unlock: xfs_iunlock(ip, lockmode); return error; } int xfs_get_blocks( struct inode *inode, sector_t iblock, struct buffer_head *bh_result, int create) { return __xfs_get_blocks(inode, iblock, bh_result, create, false); } int xfs_get_blocks_direct( struct inode *inode, sector_t iblock, struct buffer_head *bh_result, int create) { return __xfs_get_blocks(inode, iblock, bh_result, create, true); } static void __xfs_end_io_direct_write( struct inode *inode, struct xfs_ioend *ioend, loff_t offset, ssize_t size) { struct xfs_mount *mp = XFS_I(inode)->i_mount; if (XFS_FORCED_SHUTDOWN(mp) || ioend->io_error) goto out_end_io; /* * dio completion end_io functions are only called on writes if more * than 0 bytes was written. */ ASSERT(size > 0); /* * The ioend only maps whole blocks, while the IO may be sector aligned. * Hence the ioend offset/size may not match the IO offset/size exactly. * Because we don't map overwrites within EOF into the ioend, the offset * may not match, but only if the endio spans EOF. Either way, write * the IO sizes into the ioend so that completion processing does the * right thing. */ ASSERT(offset + size <= ioend->io_offset + ioend->io_size); ioend->io_size = size; ioend->io_offset = offset; /* * The ioend tells us whether we are doing unwritten extent conversion * or an append transaction that updates the on-disk file size. These * cases are the only cases where we should *potentially* be needing * to update the VFS inode size. * * We need to update the in-core inode size here so that we don't end up * with the on-disk inode size being outside the in-core inode size. We * have no other method of updating EOF for AIO, so always do it here * if necessary. * * We need to lock the test/set EOF update as we can be racing with * other IO completions here to update the EOF. Failing to serialise * here can result in EOF moving backwards and Bad Things Happen when * that occurs. */ spin_lock(&XFS_I(inode)->i_flags_lock); if (offset + size > i_size_read(inode)) i_size_write(inode, offset + size); spin_unlock(&XFS_I(inode)->i_flags_lock); /* * If we are doing an append IO that needs to update the EOF on disk, * do the transaction reserve now so we can use common end io * processing. Stashing the error (if there is one) in the ioend will * result in the ioend processing passing on the error if it is * possible as we can't return it from here. */ if (ioend->io_type == XFS_IO_OVERWRITE) ioend->io_error = xfs_setfilesize_trans_alloc(ioend); out_end_io: xfs_end_io(&ioend->io_work); return; } /* * Complete a direct I/O write request. * * The ioend structure is passed from __xfs_get_blocks() to tell us what to do. * If no ioend exists (i.e. @private == NULL) then the write IO is an overwrite * wholly within the EOF and so there is nothing for us to do. Note that in this * case the completion can be called in interrupt context, whereas if we have an * ioend we will always be called in task context (i.e. from a workqueue). */ STATIC void xfs_end_io_direct_write( struct kiocb *iocb, loff_t offset, ssize_t size, void *private) { struct inode *inode = file_inode(iocb->ki_filp); struct xfs_ioend *ioend = private; trace_xfs_gbmap_direct_endio(XFS_I(inode), offset, size, ioend ? ioend->io_type : 0, NULL); if (!ioend) { ASSERT(offset + size <= i_size_read(inode)); return; } __xfs_end_io_direct_write(inode, ioend, offset, size); } /* * For DAX we need a mapping buffer callback for unwritten extent conversion * when page faults allocate blocks and then zero them. Note that in this * case the mapping indicated by the ioend may extend beyond EOF. We most * definitely do not want to extend EOF here, so we trim back the ioend size to * EOF. */ #ifdef CONFIG_FS_DAX void xfs_end_io_dax_write( struct buffer_head *bh, int uptodate) { struct xfs_ioend *ioend = bh->b_private; struct inode *inode = ioend->io_inode; ssize_t size = ioend->io_size; ASSERT(IS_DAX(ioend->io_inode)); /* if there was an error zeroing, then don't convert it */ if (!uptodate) ioend->io_error = -EIO; /* * Trim update to EOF, so we don't extend EOF during unwritten extent * conversion of partial EOF blocks. */ spin_lock(&XFS_I(inode)->i_flags_lock); if (ioend->io_offset + size > i_size_read(inode)) size = i_size_read(inode) - ioend->io_offset; spin_unlock(&XFS_I(inode)->i_flags_lock); __xfs_end_io_direct_write(inode, ioend, ioend->io_offset, size); } #else void xfs_end_io_dax_write(struct buffer_head *bh, int uptodate) { } #endif STATIC ssize_t xfs_vm_direct_IO( struct kiocb *iocb, struct iov_iter *iter, loff_t offset) { struct inode *inode = iocb->ki_filp->f_mapping->host; struct block_device *bdev = xfs_find_bdev_for_inode(inode); if (iov_iter_rw(iter) == WRITE) { return __blockdev_direct_IO(iocb, inode, bdev, iter, offset, xfs_get_blocks_direct, xfs_end_io_direct_write, NULL, DIO_ASYNC_EXTEND); } return __blockdev_direct_IO(iocb, inode, bdev, iter, offset, xfs_get_blocks_direct, NULL, NULL, 0); } /* * Punch out the delalloc blocks we have already allocated. * * Don't bother with xfs_setattr given that nothing can have made it to disk yet * as the page is still locked at this point. */ STATIC void xfs_vm_kill_delalloc_range( struct inode *inode, loff_t start, loff_t end) { struct xfs_inode *ip = XFS_I(inode); xfs_fileoff_t start_fsb; xfs_fileoff_t end_fsb; int error; start_fsb = XFS_B_TO_FSB(ip->i_mount, start); end_fsb = XFS_B_TO_FSB(ip->i_mount, end); if (end_fsb <= start_fsb) return; xfs_ilock(ip, XFS_ILOCK_EXCL); error = xfs_bmap_punch_delalloc_range(ip, start_fsb, end_fsb - start_fsb); if (error) { /* something screwed, just bail */ if (!XFS_FORCED_SHUTDOWN(ip->i_mount)) { xfs_alert(ip->i_mount, "xfs_vm_write_failed: unable to clean up ino %lld", ip->i_ino); } } xfs_iunlock(ip, XFS_ILOCK_EXCL); } STATIC void xfs_vm_write_failed( struct inode *inode, struct page *page, loff_t pos, unsigned len) { loff_t block_offset; loff_t block_start; loff_t block_end; loff_t from = pos & (PAGE_CACHE_SIZE - 1); loff_t to = from + len; struct buffer_head *bh, *head; /* * The request pos offset might be 32 or 64 bit, this is all fine * on 64-bit platform. However, for 64-bit pos request on 32-bit * platform, the high 32-bit will be masked off if we evaluate the * block_offset via (pos & PAGE_MASK) because the PAGE_MASK is * 0xfffff000 as an unsigned long, hence the result is incorrect * which could cause the following ASSERT failed in most cases. * In order to avoid this, we can evaluate the block_offset of the * start of the page by using shifts rather than masks the mismatch * problem. */ block_offset = (pos >> PAGE_CACHE_SHIFT) << PAGE_CACHE_SHIFT; ASSERT(block_offset + from == pos); head = page_buffers(page); block_start = 0; for (bh = head; bh != head || !block_start; bh = bh->b_this_page, block_start = block_end, block_offset += bh->b_size) { block_end = block_start + bh->b_size; /* skip buffers before the write */ if (block_end <= from) continue; /* if the buffer is after the write, we're done */ if (block_start >= to) break; if (!buffer_delay(bh)) continue; if (!buffer_new(bh) && block_offset < i_size_read(inode)) continue; xfs_vm_kill_delalloc_range(inode, block_offset, block_offset + bh->b_size); /* * This buffer does not contain data anymore. make sure anyone * who finds it knows that for certain. */ clear_buffer_delay(bh); clear_buffer_uptodate(bh); clear_buffer_mapped(bh); clear_buffer_new(bh); clear_buffer_dirty(bh); } } /* * This used to call block_write_begin(), but it unlocks and releases the page * on error, and we need that page to be able to punch stale delalloc blocks out * on failure. hence we copy-n-waste it here and call xfs_vm_write_failed() at * the appropriate point. */ STATIC int xfs_vm_write_begin( struct file *file, struct address_space *mapping, loff_t pos, unsigned len, unsigned flags, struct page **pagep, void **fsdata) { pgoff_t index = pos >> PAGE_CACHE_SHIFT; struct page *page; int status; ASSERT(len <= PAGE_CACHE_SIZE); page = grab_cache_page_write_begin(mapping, index, flags); if (!page) return -ENOMEM; status = __block_write_begin(page, pos, len, xfs_get_blocks); if (unlikely(status)) { struct inode *inode = mapping->host; size_t isize = i_size_read(inode); xfs_vm_write_failed(inode, page, pos, len); unlock_page(page); /* * If the write is beyond EOF, we only want to kill blocks * allocated in this write, not blocks that were previously * written successfully. */ if (pos + len > isize) { ssize_t start = max_t(ssize_t, pos, isize); truncate_pagecache_range(inode, start, pos + len); } page_cache_release(page); page = NULL; } *pagep = page; return status; } /* * On failure, we only need to kill delalloc blocks beyond EOF in the range of * this specific write because they will never be written. Previous writes * beyond EOF where block allocation succeeded do not need to be trashed, so * only new blocks from this write should be trashed. For blocks within * EOF, generic_write_end() zeros them so they are safe to leave alone and be * written with all the other valid data. */ STATIC int xfs_vm_write_end( struct file *file, struct address_space *mapping, loff_t pos, unsigned len, unsigned copied, struct page *page, void *fsdata) { int ret; ASSERT(len <= PAGE_CACHE_SIZE); ret = generic_write_end(file, mapping, pos, len, copied, page, fsdata); if (unlikely(ret < len)) { struct inode *inode = mapping->host; size_t isize = i_size_read(inode); loff_t to = pos + len; if (to > isize) { /* only kill blocks in this write beyond EOF */ if (pos > isize) isize = pos; xfs_vm_kill_delalloc_range(inode, isize, to); truncate_pagecache_range(inode, isize, to); } } return ret; } STATIC sector_t xfs_vm_bmap( struct address_space *mapping, sector_t block) { struct inode *inode = (struct inode *)mapping->host; struct xfs_inode *ip = XFS_I(inode); trace_xfs_vm_bmap(XFS_I(inode)); xfs_ilock(ip, XFS_IOLOCK_SHARED); filemap_write_and_wait(mapping); xfs_iunlock(ip, XFS_IOLOCK_SHARED); return generic_block_bmap(mapping, block, xfs_get_blocks); } STATIC int xfs_vm_readpage( struct file *unused, struct page *page) { return mpage_readpage(page, xfs_get_blocks); } STATIC int xfs_vm_readpages( struct file *unused, struct address_space *mapping, struct list_head *pages, unsigned nr_pages) { return mpage_readpages(mapping, pages, nr_pages, xfs_get_blocks); } /* * This is basically a copy of __set_page_dirty_buffers() with one * small tweak: buffers beyond EOF do not get marked dirty. If we mark them * dirty, we'll never be able to clean them because we don't write buffers * beyond EOF, and that means we can't invalidate pages that span EOF * that have been marked dirty. Further, the dirty state can leak into * the file interior if the file is extended, resulting in all sorts of * bad things happening as the state does not match the underlying data. * * XXX: this really indicates that bufferheads in XFS need to die. Warts like * this only exist because of bufferheads and how the generic code manages them. */ STATIC int xfs_vm_set_page_dirty( struct page *page) { struct address_space *mapping = page->mapping; struct inode *inode = mapping->host; loff_t end_offset; loff_t offset; int newly_dirty; if (unlikely(!mapping)) return !TestSetPageDirty(page); end_offset = i_size_read(inode); offset = page_offset(page); spin_lock(&mapping->private_lock); if (page_has_buffers(page)) { struct buffer_head *head = page_buffers(page); struct buffer_head *bh = head; do { if (offset < end_offset) set_buffer_dirty(bh); bh = bh->b_this_page; offset += 1 << inode->i_blkbits; } while (bh != head); } newly_dirty = !TestSetPageDirty(page); spin_unlock(&mapping->private_lock); if (newly_dirty) { /* sigh - __set_page_dirty() is static, so copy it here, too */ unsigned long flags; spin_lock_irqsave(&mapping->tree_lock, flags); if (page->mapping) { /* Race with truncate? */ WARN_ON_ONCE(!PageUptodate(page)); account_page_dirtied(page, mapping); radix_tree_tag_set(&mapping->page_tree, page_index(page), PAGECACHE_TAG_DIRTY); } spin_unlock_irqrestore(&mapping->tree_lock, flags); __mark_inode_dirty(mapping->host, I_DIRTY_PAGES); } return newly_dirty; } const struct address_space_operations xfs_address_space_operations = { .readpage = xfs_vm_readpage, .readpages = xfs_vm_readpages, .writepage = xfs_vm_writepage, .writepages = xfs_vm_writepages, .set_page_dirty = xfs_vm_set_page_dirty, .releasepage = xfs_vm_releasepage, .invalidatepage = xfs_vm_invalidatepage, .write_begin = xfs_vm_write_begin, .write_end = xfs_vm_write_end, .bmap = xfs_vm_bmap, .direct_IO = xfs_vm_direct_IO, .migratepage = buffer_migrate_page, .is_partially_uptodate = block_is_partially_uptodate, .error_remove_page = generic_error_remove_page, };