| /* |
| * 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 "xfs_reflink.h" |
| #include <linux/gfp.h> |
| #include <linux/mpage.h> |
| #include <linux/pagevec.h> |
| #include <linux/writeback.h> |
| |
| /* flags for direct write completions */ |
| #define XFS_DIO_FLAG_UNWRITTEN (1 << 0) |
| #define XFS_DIO_FLAG_APPEND (1 << 1) |
| #define XFS_DIO_FLAG_COW (1 << 2) |
| |
| /* |
| * structure owned by writepages passed to individual writepage calls |
| */ |
| struct xfs_writepage_ctx { |
| struct xfs_bmbt_irec imap; |
| bool imap_valid; |
| unsigned int io_type; |
| struct xfs_ioend *ioend; |
| sector_t last_block; |
| }; |
| |
| 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); |
| } |
| |
| 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 page. Update the page state via the |
| * associated buffer_heads, paying attention to the start and end offsets that |
| * we need to process on the page. |
| * |
| * Landmine Warning: bh->b_end_io() will call end_page_writeback() on the last |
| * buffer in the IO. Once it does this, it is unsafe to access the bufferhead or |
| * the page at all, as we may be racing with memory reclaim and it can free both |
| * the bufferhead chain and the page as it will see the page as clean and |
| * unused. |
| */ |
| static void |
| xfs_finish_page_writeback( |
| struct inode *inode, |
| struct bio_vec *bvec, |
| int error) |
| { |
| unsigned int end = bvec->bv_offset + bvec->bv_len - 1; |
| struct buffer_head *head, *bh, *next; |
| unsigned int off = 0; |
| unsigned int bsize; |
| |
| ASSERT(bvec->bv_offset < PAGE_SIZE); |
| ASSERT((bvec->bv_offset & (i_blocksize(inode) - 1)) == 0); |
| ASSERT(end < PAGE_SIZE); |
| ASSERT((bvec->bv_len & (i_blocksize(inode) - 1)) == 0); |
| |
| bh = head = page_buffers(bvec->bv_page); |
| |
| bsize = bh->b_size; |
| do { |
| if (off > end) |
| break; |
| next = bh->b_this_page; |
| if (off < bvec->bv_offset) |
| goto next_bh; |
| bh->b_end_io(bh, !error); |
| next_bh: |
| off += bsize; |
| } while ((bh = next) != head); |
| } |
| |
| /* |
| * We're now finished for good with this ioend structure. Update the page |
| * state, release holds on bios, and finally free up memory. Do not use the |
| * ioend after this. |
| */ |
| STATIC void |
| xfs_destroy_ioend( |
| struct xfs_ioend *ioend, |
| int error) |
| { |
| struct inode *inode = ioend->io_inode; |
| struct bio *last = ioend->io_bio; |
| struct bio *bio, *next; |
| |
| for (bio = &ioend->io_inline_bio; bio; bio = next) { |
| struct bio_vec *bvec; |
| int i; |
| |
| /* |
| * For the last bio, bi_private points to the ioend, so we |
| * need to explicitly end the iteration here. |
| */ |
| if (bio == last) |
| next = NULL; |
| else |
| next = bio->bi_private; |
| |
| /* walk each page on bio, ending page IO on them */ |
| bio_for_each_segment_all(bvec, bio, i) |
| xfs_finish_page_writeback(inode, bvec, error); |
| |
| bio_put(bio); |
| } |
| } |
| |
| /* |
| * 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; |
| |
| error = xfs_trans_alloc(mp, &M_RES(mp)->tr_fsyncts, 0, 0, 0, &tp); |
| if (error) |
| return error; |
| |
| ioend->io_append_trans = tp; |
| |
| /* |
| * We may pass freeze protection with a transaction. So tell lockdep |
| * we released it. |
| */ |
| __sb_writers_release(ioend->io_inode->i_sb, SB_FREEZE_FS); |
| /* |
| * 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); |
| 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); |
| } |
| |
| int |
| xfs_setfilesize( |
| struct xfs_inode *ip, |
| xfs_off_t offset, |
| size_t size) |
| { |
| struct xfs_mount *mp = ip->i_mount; |
| struct xfs_trans *tp; |
| int error; |
| |
| error = xfs_trans_alloc(mp, &M_RES(mp)->tr_fsyncts, 0, 0, 0, &tp); |
| if (error) |
| return error; |
| |
| return __xfs_setfilesize(ip, tp, offset, size); |
| } |
| |
| STATIC int |
| xfs_setfilesize_ioend( |
| struct xfs_ioend *ioend, |
| int error) |
| { |
| 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); |
| __sb_writers_acquired(VFS_I(ip)->i_sb, SB_FREEZE_FS); |
| |
| /* we abort the update if there was an IO error */ |
| if (error) { |
| xfs_trans_cancel(tp); |
| return error; |
| } |
| |
| return __xfs_setfilesize(ip, tp, ioend->io_offset, ioend->io_size); |
| } |
| |
| /* |
| * IO write completion. |
| */ |
| STATIC void |
| xfs_end_io( |
| struct work_struct *work) |
| { |
| struct xfs_ioend *ioend = |
| container_of(work, struct xfs_ioend, io_work); |
| struct xfs_inode *ip = XFS_I(ioend->io_inode); |
| xfs_off_t offset = ioend->io_offset; |
| size_t size = ioend->io_size; |
| int error = ioend->io_bio->bi_error; |
| |
| /* |
| * Just clean up the in-memory strutures if the fs has been shut down. |
| */ |
| if (XFS_FORCED_SHUTDOWN(ip->i_mount)) { |
| error = -EIO; |
| goto done; |
| } |
| |
| /* |
| * Clean up any COW blocks on an I/O error. |
| */ |
| if (unlikely(error)) { |
| switch (ioend->io_type) { |
| case XFS_IO_COW: |
| xfs_reflink_cancel_cow_range(ip, offset, size, true); |
| break; |
| } |
| |
| goto done; |
| } |
| |
| /* |
| * Success: commit the COW or unwritten blocks if needed. |
| */ |
| switch (ioend->io_type) { |
| case XFS_IO_COW: |
| error = xfs_reflink_end_cow(ip, offset, size); |
| break; |
| case XFS_IO_UNWRITTEN: |
| error = xfs_iomap_write_unwritten(ip, offset, size); |
| break; |
| default: |
| ASSERT(!xfs_ioend_is_append(ioend) || ioend->io_append_trans); |
| break; |
| } |
| |
| done: |
| if (ioend->io_append_trans) |
| error = xfs_setfilesize_ioend(ioend, error); |
| xfs_destroy_ioend(ioend, error); |
| } |
| |
| STATIC void |
| xfs_end_bio( |
| struct bio *bio) |
| { |
| struct xfs_ioend *ioend = bio->bi_private; |
| struct xfs_mount *mp = XFS_I(ioend->io_inode)->i_mount; |
| |
| if (ioend->io_type == XFS_IO_UNWRITTEN || ioend->io_type == XFS_IO_COW) |
| 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, bio->bi_error); |
| } |
| |
| STATIC int |
| xfs_map_blocks( |
| struct inode *inode, |
| loff_t offset, |
| struct xfs_bmbt_irec *imap, |
| int type) |
| { |
| struct xfs_inode *ip = XFS_I(inode); |
| struct xfs_mount *mp = ip->i_mount; |
| ssize_t count = i_blocksize(inode); |
| 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; |
| |
| ASSERT(type != XFS_IO_COW); |
| if (type == XFS_IO_UNWRITTEN) |
| bmapi_flags |= XFS_BMAPI_IGSTATE; |
| |
| 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); |
| /* |
| * Truncate an overwrite extent if there's a pending CoW |
| * reservation before the end of this extent. This forces us |
| * to come back to writepage to take care of the CoW. |
| */ |
| if (nimaps && type == XFS_IO_OVERWRITE) |
| xfs_reflink_trim_irec_to_next_cow(ip, offset_fsb, imap); |
| 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, XFS_DATA_FORK, 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 bool |
| 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; |
| } |
| |
| 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) |
| { |
| 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); |
| } |
| |
| 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 the bio for an ioend. We are passed an ioend with a bio attached to |
| * it, and we submit that bio. The ioend may be used for multiple bio |
| * submissions, so we only want to allocate an append transaction for the ioend |
| * once. In the case of multiple bio submission, each bio will take an IO |
| * reference to the ioend to ensure that the ioend completion is only done once |
| * all bios have been submitted and the ioend is really done. |
| * |
| * 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 bio and ioend |
| * rather than submit it to IO. This typically only happens on a filesystem |
| * shutdown. |
| */ |
| STATIC int |
| xfs_submit_ioend( |
| struct writeback_control *wbc, |
| struct xfs_ioend *ioend, |
| int status) |
| { |
| /* Convert CoW extents to regular */ |
| if (!status && ioend->io_type == XFS_IO_COW) { |
| status = xfs_reflink_convert_cow(XFS_I(ioend->io_inode), |
| ioend->io_offset, ioend->io_size); |
| } |
| |
| /* Reserve log space if we might write beyond the on-disk inode size. */ |
| if (!status && |
| ioend->io_type != XFS_IO_UNWRITTEN && |
| xfs_ioend_is_append(ioend) && |
| !ioend->io_append_trans) |
| status = xfs_setfilesize_trans_alloc(ioend); |
| |
| ioend->io_bio->bi_private = ioend; |
| ioend->io_bio->bi_end_io = xfs_end_bio; |
| bio_set_op_attrs(ioend->io_bio, REQ_OP_WRITE, |
| (wbc->sync_mode == WB_SYNC_ALL) ? WRITE_SYNC : 0); |
| /* |
| * 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 (status) { |
| ioend->io_bio->bi_error = status; |
| bio_endio(ioend->io_bio); |
| return status; |
| } |
| |
| submit_bio(ioend->io_bio); |
| return 0; |
| } |
| |
| static void |
| xfs_init_bio_from_bh( |
| struct bio *bio, |
| struct buffer_head *bh) |
| { |
| bio->bi_iter.bi_sector = bh->b_blocknr * (bh->b_size >> 9); |
| bio->bi_bdev = bh->b_bdev; |
| } |
| |
| static struct xfs_ioend * |
| xfs_alloc_ioend( |
| struct inode *inode, |
| unsigned int type, |
| xfs_off_t offset, |
| struct buffer_head *bh) |
| { |
| struct xfs_ioend *ioend; |
| struct bio *bio; |
| |
| bio = bio_alloc_bioset(GFP_NOFS, BIO_MAX_PAGES, xfs_ioend_bioset); |
| xfs_init_bio_from_bh(bio, bh); |
| |
| ioend = container_of(bio, struct xfs_ioend, io_inline_bio); |
| INIT_LIST_HEAD(&ioend->io_list); |
| ioend->io_type = type; |
| ioend->io_inode = inode; |
| ioend->io_size = 0; |
| ioend->io_offset = offset; |
| INIT_WORK(&ioend->io_work, xfs_end_io); |
| ioend->io_append_trans = NULL; |
| ioend->io_bio = bio; |
| return ioend; |
| } |
| |
| /* |
| * Allocate a new bio, and chain the old bio to the new one. |
| * |
| * Note that we have to do perform the chaining in this unintuitive order |
| * so that the bi_private linkage is set up in the right direction for the |
| * traversal in xfs_destroy_ioend(). |
| */ |
| static void |
| xfs_chain_bio( |
| struct xfs_ioend *ioend, |
| struct writeback_control *wbc, |
| struct buffer_head *bh) |
| { |
| struct bio *new; |
| |
| new = bio_alloc(GFP_NOFS, BIO_MAX_PAGES); |
| xfs_init_bio_from_bh(new, bh); |
| |
| bio_chain(ioend->io_bio, new); |
| bio_get(ioend->io_bio); /* for xfs_destroy_ioend */ |
| bio_set_op_attrs(ioend->io_bio, REQ_OP_WRITE, |
| (wbc->sync_mode == WB_SYNC_ALL) ? WRITE_SYNC : 0); |
| submit_bio(ioend->io_bio); |
| ioend->io_bio = new; |
| } |
| |
| /* |
| * 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 the ioend we finished off so that the caller can submit it |
| * once it has finished processing the dirty page. |
| */ |
| STATIC void |
| xfs_add_to_ioend( |
| struct inode *inode, |
| struct buffer_head *bh, |
| xfs_off_t offset, |
| struct xfs_writepage_ctx *wpc, |
| struct writeback_control *wbc, |
| struct list_head *iolist) |
| { |
| if (!wpc->ioend || wpc->io_type != wpc->ioend->io_type || |
| bh->b_blocknr != wpc->last_block + 1 || |
| offset != wpc->ioend->io_offset + wpc->ioend->io_size) { |
| if (wpc->ioend) |
| list_add(&wpc->ioend->io_list, iolist); |
| wpc->ioend = xfs_alloc_ioend(inode, wpc->io_type, offset, bh); |
| } |
| |
| /* |
| * If the buffer doesn't fit into the bio we need to allocate a new |
| * one. This shouldn't happen more than once for a given buffer. |
| */ |
| while (xfs_bio_add_buffer(wpc->ioend->io_bio, bh) != bh->b_size) |
| xfs_chain_bio(wpc->ioend, wbc, bh); |
| |
| wpc->ioend->io_size += bh->b_size; |
| wpc->last_block = bh->b_blocknr; |
| xfs_start_buffer_writeback(bh); |
| } |
| |
| 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; |
| } |
| |
| 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 += i_blocksize(inode); |
| |
| } while ((bh = bh->b_this_page) != head); |
| |
| xfs_iunlock(ip, XFS_ILOCK_EXCL); |
| out_invalidate: |
| xfs_vm_invalidatepage(page, 0, PAGE_SIZE); |
| return; |
| } |
| |
| static int |
| xfs_map_cow( |
| struct xfs_writepage_ctx *wpc, |
| struct inode *inode, |
| loff_t offset, |
| unsigned int *new_type) |
| { |
| struct xfs_inode *ip = XFS_I(inode); |
| struct xfs_bmbt_irec imap; |
| bool is_cow = false, need_alloc = false; |
| int error; |
| |
| /* |
| * If we already have a valid COW mapping keep using it. |
| */ |
| if (wpc->io_type == XFS_IO_COW) { |
| wpc->imap_valid = xfs_imap_valid(inode, &wpc->imap, offset); |
| if (wpc->imap_valid) { |
| *new_type = XFS_IO_COW; |
| return 0; |
| } |
| } |
| |
| /* |
| * Else we need to check if there is a COW mapping at this offset. |
| */ |
| xfs_ilock(ip, XFS_ILOCK_SHARED); |
| is_cow = xfs_reflink_find_cow_mapping(ip, offset, &imap, &need_alloc); |
| xfs_iunlock(ip, XFS_ILOCK_SHARED); |
| |
| if (!is_cow) |
| return 0; |
| |
| /* |
| * And if the COW mapping has a delayed extent here we need to |
| * allocate real space for it now. |
| */ |
| if (need_alloc) { |
| error = xfs_iomap_write_allocate(ip, XFS_COW_FORK, offset, |
| &imap); |
| if (error) |
| return error; |
| } |
| |
| wpc->io_type = *new_type = XFS_IO_COW; |
| wpc->imap_valid = true; |
| wpc->imap = imap; |
| return 0; |
| } |
| |
| /* |
| * We implement an immediate ioend submission policy here to avoid needing to |
| * chain multiple ioends and hence nest mempool allocations which can violate |
| * forward progress guarantees we need to provide. The current ioend we are |
| * adding buffers to is cached on the writepage context, and if the new buffer |
| * does not append to the cached ioend it will create a new ioend and cache that |
| * instead. |
| * |
| * If a new ioend is created and cached, the old ioend is returned and queued |
| * locally for submission once the entire page is processed or an error has been |
| * detected. While ioends are submitted immediately after they are completed, |
| * batching optimisations are provided by higher level block plugging. |
| * |
| * At the end of a writeback pass, there will be a cached ioend remaining on the |
| * writepage context that the caller will need to submit. |
| */ |
| static int |
| xfs_writepage_map( |
| struct xfs_writepage_ctx *wpc, |
| struct writeback_control *wbc, |
| struct inode *inode, |
| struct page *page, |
| loff_t offset, |
| __uint64_t end_offset) |
| { |
| LIST_HEAD(submit_list); |
| struct xfs_ioend *ioend, *next; |
| struct buffer_head *bh, *head; |
| ssize_t len = i_blocksize(inode); |
| int error = 0; |
| int count = 0; |
| int uptodate = 1; |
| unsigned int new_type; |
| |
| bh = head = page_buffers(page); |
| offset = page_offset(page); |
| do { |
| 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)) { |
| wpc->imap_valid = false; |
| continue; |
| } |
| |
| if (buffer_unwritten(bh)) |
| new_type = XFS_IO_UNWRITTEN; |
| else if (buffer_delay(bh)) |
| new_type = XFS_IO_DELALLOC; |
| else if (buffer_uptodate(bh)) |
| new_type = XFS_IO_OVERWRITE; |
| 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. |
| */ |
| wpc->imap_valid = false; |
| continue; |
| } |
| |
| if (xfs_is_reflink_inode(XFS_I(inode))) { |
| error = xfs_map_cow(wpc, inode, offset, &new_type); |
| if (error) |
| goto out; |
| } |
| |
| if (wpc->io_type != new_type) { |
| wpc->io_type = new_type; |
| wpc->imap_valid = false; |
| } |
| |
| if (wpc->imap_valid) |
| wpc->imap_valid = xfs_imap_valid(inode, &wpc->imap, |
| offset); |
| if (!wpc->imap_valid) { |
| error = xfs_map_blocks(inode, offset, &wpc->imap, |
| wpc->io_type); |
| if (error) |
| goto out; |
| wpc->imap_valid = xfs_imap_valid(inode, &wpc->imap, |
| offset); |
| } |
| if (wpc->imap_valid) { |
| lock_buffer(bh); |
| if (wpc->io_type != XFS_IO_OVERWRITE) |
| xfs_map_at_offset(inode, bh, &wpc->imap, offset); |
| xfs_add_to_ioend(inode, bh, offset, wpc, wbc, &submit_list); |
| count++; |
| } |
| |
| } while (offset += len, ((bh = bh->b_this_page) != head)); |
| |
| if (uptodate && bh == head) |
| SetPageUptodate(page); |
| |
| ASSERT(wpc->ioend || list_empty(&submit_list)); |
| |
| out: |
| /* |
| * On error, we have to fail the ioend here because we have locked |
| * buffers in the ioend. If we don't do this, we'll deadlock |
| * invalidating the page as that tries to lock the buffers on the page. |
| * Also, because we may have set pages under writeback, we have to make |
| * sure we run IO completion to mark the error state of the IO |
| * appropriately, so we can't cancel the ioend directly here. That means |
| * we have to mark this page as under writeback if we included any |
| * buffers from it in the ioend chain so that completion treats it |
| * correctly. |
| * |
| * If we didn't include the page in the ioend, the on error we can |
| * simply discard and unlock it as there are no other users of the page |
| * or it's buffers right now. The caller will still need to trigger |
| * submission of outstanding ioends on the writepage context so they are |
| * treated correctly on error. |
| */ |
| if (count) { |
| xfs_start_page_writeback(page, !error); |
| |
| /* |
| * Preserve the original error if there was one, otherwise catch |
| * submission errors here and propagate into subsequent ioend |
| * submissions. |
| */ |
| list_for_each_entry_safe(ioend, next, &submit_list, io_list) { |
| int error2; |
| |
| list_del_init(&ioend->io_list); |
| error2 = xfs_submit_ioend(wbc, ioend, error); |
| if (error2 && !error) |
| error = error2; |
| } |
| } else if (error) { |
| xfs_aops_discard_page(page); |
| ClearPageUptodate(page); |
| unlock_page(page); |
| } else { |
| /* |
| * We can end up here with no error and nothing to write if we |
| * race with a partial page truncate on a sub-page block sized |
| * filesystem. In that case we need to mark the page clean. |
| */ |
| xfs_start_page_writeback(page, 1); |
| end_page_writeback(page); |
| } |
| |
| mapping_set_error(page->mapping, error); |
| return error; |
| } |
| |
| /* |
| * 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_do_writepage( |
| struct page *page, |
| struct writeback_control *wbc, |
| void *data) |
| { |
| struct xfs_writepage_ctx *wpc = data; |
| struct inode *inode = page->mapping->host; |
| loff_t offset; |
| __uint64_t end_offset; |
| pgoff_t end_index; |
| |
| 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? |
| * |
| * 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 | |
| * ---------------------------------^------------------| |
| */ |
| offset = i_size_read(inode); |
| end_index = offset >> PAGE_SHIFT; |
| if (page->index < end_index) |
| end_offset = (xfs_off_t)(page->index + 1) << PAGE_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_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_SIZE); |
| |
| /* Adjust the end_offset to the end of file */ |
| end_offset = offset; |
| } |
| |
| return xfs_writepage_map(wpc, wbc, inode, page, offset, end_offset); |
| |
| redirty: |
| redirty_page_for_writepage(wbc, page); |
| unlock_page(page); |
| return 0; |
| } |
| |
| STATIC int |
| xfs_vm_writepage( |
| struct page *page, |
| struct writeback_control *wbc) |
| { |
| struct xfs_writepage_ctx wpc = { |
| .io_type = XFS_IO_INVALID, |
| }; |
| int ret; |
| |
| ret = xfs_do_writepage(page, wbc, &wpc); |
| if (wpc.ioend) |
| ret = xfs_submit_ioend(wbc, wpc.ioend, ret); |
| return ret; |
| } |
| |
| STATIC int |
| xfs_vm_writepages( |
| struct address_space *mapping, |
| struct writeback_control *wbc) |
| { |
| struct xfs_writepage_ctx wpc = { |
| .io_type = XFS_IO_INVALID, |
| }; |
| int ret; |
| |
| xfs_iflags_clear(XFS_I(mapping->host), XFS_ITRUNCATED); |
| if (dax_mapping(mapping)) |
| return dax_writeback_mapping_range(mapping, |
| xfs_find_bdev_for_inode(mapping->host), wbc); |
| |
| ret = write_cache_pages(mapping, wbc, xfs_do_writepage, &wpc); |
| if (wpc.ioend) |
| ret = xfs_submit_ioend(wbc, wpc.ioend, ret); |
| return ret; |
| } |
| |
| /* |
| * 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); |
| |
| /* |
| * mm accommodates an old ext3 case where clean pages might not have had |
| * the dirty bit cleared. Thus, it can send actual dirty pages to |
| * ->releasepage() via shrink_active_list(). Conversely, |
| * block_invalidatepage() can send pages that are still marked dirty |
| * but otherwise have invalidated buffers. |
| * |
| * We want to release the latter to avoid unnecessary buildup of the |
| * LRU, skip the former and warn if we've left any lingering |
| * delalloc/unwritten buffers on clean pages. Skip pages with delalloc |
| * or unwritten buffers and warn if the page is not dirty. Otherwise |
| * try to release the buffers. |
| */ |
| xfs_count_page_state(page, &delalloc, &unwritten); |
| |
| if (delalloc) { |
| WARN_ON_ONCE(!PageDirty(page)); |
| return 0; |
| } |
| if (unwritten) { |
| WARN_ON_ONCE(!PageDirty(page)); |
| return 0; |
| } |
| |
| return try_to_free_buffers(page); |
| } |
| |
| /* |
| * When we map a DIO buffer, we may need to pass flags to |
| * xfs_end_io_direct_write to tell it what kind of write IO we are doing. |
| * |
| * Note that for DIO, an IO to the highest supported file block offset (i.e. |
| * 2^63 - 1FSB bytes) will result in the offset + count overflowing a signed 64 |
| * bit variable. Hence if we see this overflow, we have to assume that the IO is |
| * extending the file size. We won't know for sure until IO completion is run |
| * and the actual max write offset is communicated to the IO completion |
| * routine. |
| */ |
| static void |
| xfs_map_direct( |
| struct inode *inode, |
| struct buffer_head *bh_result, |
| struct xfs_bmbt_irec *imap, |
| xfs_off_t offset, |
| bool is_cow) |
| { |
| uintptr_t *flags = (uintptr_t *)&bh_result->b_private; |
| xfs_off_t size = bh_result->b_size; |
| |
| trace_xfs_get_blocks_map_direct(XFS_I(inode), offset, size, |
| ISUNWRITTEN(imap) ? XFS_IO_UNWRITTEN : is_cow ? XFS_IO_COW : |
| XFS_IO_OVERWRITE, imap); |
| |
| if (ISUNWRITTEN(imap)) { |
| *flags |= XFS_DIO_FLAG_UNWRITTEN; |
| set_buffer_defer_completion(bh_result); |
| } else if (is_cow) { |
| *flags |= XFS_DIO_FLAG_COW; |
| set_buffer_defer_completion(bh_result); |
| } |
| if (offset + size > i_size_read(inode) || offset + size < 0) { |
| *flags |= XFS_DIO_FLAG_APPEND; |
| set_buffer_defer_completion(bh_result); |
| } |
| } |
| |
| /* |
| * 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, |
| i_blocksize(inode)); |
| } |
| 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, |
| bool dax_fault) |
| { |
| 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; |
| bool is_cow = false; |
| bool need_alloc = false; |
| |
| BUG_ON(create && !direct); |
| |
| if (XFS_FORCED_SHUTDOWN(mp)) |
| return -EIO; |
| |
| offset = (xfs_off_t)iblock << inode->i_blkbits; |
| ASSERT(bh_result->b_size >= i_blocksize(inode)); |
| size = bh_result->b_size; |
| |
| if (!create && 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. |
| */ |
| 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); |
| |
| if (create && direct && xfs_is_reflink_inode(ip)) |
| is_cow = xfs_reflink_find_cow_mapping(ip, offset, &imap, |
| &need_alloc); |
| if (!is_cow) { |
| error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb, |
| &imap, &nimaps, XFS_BMAPI_ENTIRE); |
| /* |
| * Truncate an overwrite extent if there's a pending CoW |
| * reservation before the end of this extent. This |
| * forces us to come back to get_blocks to take care of |
| * the CoW. |
| */ |
| if (create && direct && nimaps && |
| imap.br_startblock != HOLESTARTBLOCK && |
| imap.br_startblock != DELAYSTARTBLOCK && |
| !ISUNWRITTEN(&imap)) |
| xfs_reflink_trim_irec_to_next_cow(ip, offset_fsb, |
| &imap); |
| } |
| ASSERT(!need_alloc); |
| if (error) |
| goto out_unlock; |
| |
| /* |
| * The only time we can ever safely find delalloc blocks on direct I/O |
| * is a dio write to post-eof speculative preallocation. All other |
| * scenarios are indicative of a problem or misuse (such as mixing |
| * direct and mapped I/O). |
| * |
| * The file may be unmapped by the time we get here so we cannot |
| * reliably fail the I/O based on mapping. Instead, fail the I/O if this |
| * is a read or a write within eof. Otherwise, carry on but warn as a |
| * precuation if the file happens to be mapped. |
| */ |
| if (direct && imap.br_startblock == DELAYSTARTBLOCK) { |
| if (!create || offset < i_size_read(VFS_I(ip))) { |
| WARN_ON_ONCE(1); |
| error = -EIO; |
| goto out_unlock; |
| } |
| WARN_ON_ONCE(mapping_mapped(VFS_I(ip)->i_mapping)); |
| } |
| |
| /* for DAX, we convert unwritten extents directly */ |
| if (create && |
| (!nimaps || |
| (imap.br_startblock == HOLESTARTBLOCK || |
| imap.br_startblock == DELAYSTARTBLOCK) || |
| (IS_DAX(inode) && ISUNWRITTEN(&imap)))) { |
| /* |
| * xfs_iomap_write_direct() expects the shared lock. It |
| * is unlocked on return. |
| */ |
| if (lockmode == XFS_ILOCK_EXCL) |
| xfs_ilock_demote(ip, lockmode); |
| |
| error = xfs_iomap_write_direct(ip, offset, size, |
| &imap, nimaps); |
| if (error) |
| return error; |
| new = 1; |
| |
| 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; |
| } |
| |
| if (IS_DAX(inode) && create) { |
| ASSERT(!ISUNWRITTEN(&imap)); |
| /* zeroing is not needed at a higher layer */ |
| new = 0; |
| } |
| |
| /* trim mapping down to size requested */ |
| 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) { |
| if (dax_fault) |
| ASSERT(!ISUNWRITTEN(&imap)); |
| else |
| xfs_map_direct(inode, bh_result, &imap, offset, |
| is_cow); |
| } |
| } |
| |
| /* |
| * 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); |
| |
| 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, 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, false); |
| } |
| |
| int |
| xfs_get_blocks_dax_fault( |
| struct inode *inode, |
| sector_t iblock, |
| struct buffer_head *bh_result, |
| int create) |
| { |
| return __xfs_get_blocks(inode, iblock, bh_result, create, true, true); |
| } |
| |
| /* |
| * Complete a direct I/O write request. |
| * |
| * xfs_map_direct passes us some flags in the private data to tell us what to |
| * do. If no flags are set, then the write IO is an overwrite wholly within |
| * the existing allocated file size 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 flags set we will always be called in task context |
| * (i.e. from a workqueue). |
| */ |
| int |
| 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); |
| uintptr_t flags = (uintptr_t)private; |
| int error = 0; |
| |
| trace_xfs_end_io_direct_write(ip, offset, size); |
| |
| if (XFS_FORCED_SHUTDOWN(ip->i_mount)) |
| return -EIO; |
| |
| if (size <= 0) |
| return size; |
| |
| /* |
| * The flags tell us whether we are doing unwritten extent conversions |
| * 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. |
| */ |
| if (flags == 0) { |
| ASSERT(offset + size <= i_size_read(inode)); |
| return 0; |
| } |
| |
| /* |
| * 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 (flags & XFS_DIO_FLAG_COW) |
| error = xfs_reflink_end_cow(ip, offset, size); |
| if (flags & XFS_DIO_FLAG_UNWRITTEN) { |
| trace_xfs_end_io_direct_write_unwritten(ip, offset, size); |
| |
| error = xfs_iomap_write_unwritten(ip, offset, size); |
| } |
| if (flags & XFS_DIO_FLAG_APPEND) { |
| trace_xfs_end_io_direct_write_append(ip, offset, size); |
| |
| error = xfs_setfilesize(ip, offset, size); |
| } |
| |
| return error; |
| } |
| |
| STATIC ssize_t |
| xfs_vm_direct_IO( |
| struct kiocb *iocb, |
| struct iov_iter *iter) |
| { |
| /* |
| * We just need the method present so that open/fcntl allow direct I/O. |
| */ |
| return -EINVAL; |
| } |
| |
| 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); |
| |
| /* |
| * The swap code (ab-)uses ->bmap to get a block mapping and then |
| * bypasseѕ the file system for actual I/O. We really can't allow |
| * that on reflinks inodes, so we have to skip out here. And yes, |
| * 0 is the magic code for a bmap error. |
| * |
| * Since we don't pass back blockdev info, we can't return bmap |
| * information for rt files either. |
| */ |
| if (xfs_is_reflink_inode(ip) || XFS_IS_REALTIME_INODE(ip)) { |
| xfs_iunlock(ip, XFS_IOLOCK_SHARED); |
| return 0; |
| } |
| 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) |
| { |
| trace_xfs_vm_readpage(page->mapping->host, 1); |
| 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) |
| { |
| trace_xfs_vm_readpages(mapping->host, 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 += i_blocksize(inode); |
| } while (bh != head); |
| } |
| /* |
| * Lock out page->mem_cgroup migration to keep PageDirty |
| * synchronized with per-memcg dirty page counters. |
| */ |
| lock_page_memcg(page); |
| 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); |
| } |
| unlock_page_memcg(page); |
| if (newly_dirty) |
| __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, |
| .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, |
| }; |