diff options
Diffstat (limited to 'fs/xfs/xfs_aops.c')
| -rw-r--r-- | fs/xfs/xfs_aops.c | 1931 |
1 files changed, 1931 insertions, 0 deletions
diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c new file mode 100644 index 000000000..a56960dd1 --- /dev/null +++ b/fs/xfs/xfs_aops.c @@ -0,0 +1,1931 @@ +/* + * 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 <linux/gfp.h> +#include <linux/mpage.h> +#include <linux/pagevec.h> +#include <linux/writeback.h> + +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 | <EOF> | + * ----------------------------------------------------- + * | 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 | <EOF> | + * ------------------------------------------------------- + * | 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, + int 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, 0); +} + +STATIC 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, 1); +} + +/* + * 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_inode *ip = XFS_I(inode); + struct xfs_mount *mp = ip->i_mount; + struct xfs_ioend *ioend = private; + + trace_xfs_gbmap_direct_endio(ip, offset, size, + ioend ? ioend->io_type : 0, NULL); + + if (!ioend) { + ASSERT(offset + size <= i_size_read(inode)); + return; + } + + if (XFS_FORCED_SHUTDOWN(mp)) + 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(&ip->i_flags_lock); + if (offset + size > i_size_read(inode)) + i_size_write(inode, offset + size); + spin_unlock(&ip->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; +} + +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, +}; |