From patchwork Tue Nov 29 17:28:16 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christoph Hellwig X-Patchwork-Id: 9486523 X-Mozilla-Keys: nonjunk Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on sandeen.net X-Spam-Level: X-Spam-Status: No, score=-2.0 required=5.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,RP_MATCHES_RCVD autolearn=ham autolearn_force=no version=3.4.0 X-Spam-HP: BAYES_00=-1.9,HEADER_FROM_DIFFERENT_DOMAINS=0.001, RP_MATCHES_RCVD=-0.1 X-Original-To: sandeen@sandeen.net Delivered-To: sandeen@sandeen.net Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by sandeen.net (Postfix) with ESMTP id 006304A83CA for ; Tue, 29 Nov 2016 11:27:53 -0600 (CST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756608AbcK2R2m (ORCPT ); Tue, 29 Nov 2016 12:28:42 -0500 Received: from bombadil.infradead.org ([198.137.202.9]:44504 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756587AbcK2R2l (ORCPT ); Tue, 29 Nov 2016 12:28:41 -0500 Received: from [83.175.99.196] (helo=localhost) by bombadil.infradead.org with esmtpsa (Exim 4.85_2 #1 (Red Hat Linux)) id 1cBmCr-0001T3-7O; Tue, 29 Nov 2016 17:28:40 +0000 From: Christoph Hellwig To: linux-xfs@vger.kernel.org Cc: axboe@fb.com, linux-fsdevel@vger.kernel.org Subject: [PATCH 5/5] xfs: use iomap_dio_rw Date: Tue, 29 Nov 2016 18:28:16 +0100 Message-Id: <1480440496-25737-6-git-send-email-hch@lst.de> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1480440496-25737-1-git-send-email-hch@lst.de> References: <1480440496-25737-1-git-send-email-hch@lst.de> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-xfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org Straight switch over to using iomap for direct I/O - we already have the non-COW dio path in write_begin for DAX and files with extent size hints, so nothing to add there. The COW path is ported over from the old get_blocks version and a bit of a mess, but I have some work in progress to make it look more like the buffered I/O COW path. This gets rid of xfs_get_blocks_direct and the last caller of xfs_get_blocks with the create flag set, so all that code can be removed. Last but not least I've removed a comment in xfs_filemap_fault that refers to xfs_get_blocks entirely instead of updating it - while the reference is correct, the whole DAX fault path looks different than the non-DAX one, so it seems rather pointless. Signed-off-by: Christoph Hellwig --- fs/iomap.c | 2 +- fs/xfs/xfs_aops.c | 291 ++--------------------------------------------------- fs/xfs/xfs_aops.h | 6 -- fs/xfs/xfs_file.c | 149 +++++++++++---------------- fs/xfs/xfs_iomap.c | 50 +++++++-- 5 files changed, 111 insertions(+), 387 deletions(-) diff --git a/fs/iomap.c b/fs/iomap.c index 93d36fd..fc24462 100644 --- a/fs/iomap.c +++ b/fs/iomap.c @@ -591,7 +591,7 @@ EXPORT_SYMBOL_GPL(iomap_fiemap); * iomap.h: */ #define IOMAP_DIO_WRITE (1 << 30) -#define IOMAP_DIO_DIRTY (1 << 31) +#define IOMAP_DIO_DIRTY (1 << 31) struct iomap_dio { struct kiocb *iocb; diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c index e8f6c2b..265000a 100644 --- a/fs/xfs/xfs_aops.c +++ b/fs/xfs/xfs_aops.c @@ -37,11 +37,6 @@ #include #include -/* 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 */ @@ -1176,45 +1171,6 @@ xfs_vm_releasepage( } /* - * 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. * @@ -1254,51 +1210,12 @@ xfs_map_trim_size( bh_result->b_size = mapping_size; } -/* Bounce unaligned directio writes to the page cache. */ static int -xfs_bounce_unaligned_dio_write( - struct xfs_inode *ip, - xfs_fileoff_t offset_fsb, - struct xfs_bmbt_irec *imap) -{ - struct xfs_bmbt_irec irec; - xfs_fileoff_t delta; - bool shared; - bool x; - int error; - - irec = *imap; - if (offset_fsb > irec.br_startoff) { - delta = offset_fsb - irec.br_startoff; - irec.br_blockcount -= delta; - irec.br_startblock += delta; - irec.br_startoff = offset_fsb; - } - error = xfs_reflink_trim_around_shared(ip, &irec, &shared, &x); - if (error) - return error; - - /* - * We're here because we're trying to do a directio write to a - * region that isn't aligned to a filesystem block. If any part - * of the extent is shared, fall back to buffered mode to handle - * the RMW. This is done by returning -EREMCHG ("remote addr - * changed"), which is caught further up the call stack. - */ - if (shared) { - trace_xfs_reflink_bounce_dio_write(ip, imap); - return -EREMCHG; - } - return 0; -} - -STATIC int -__xfs_get_blocks( +xfs_get_blocks( struct inode *inode, sector_t iblock, struct buffer_head *bh_result, - int create, - bool direct) + int create) { struct xfs_inode *ip = XFS_I(inode); struct xfs_mount *mp = ip->i_mount; @@ -1309,10 +1226,8 @@ __xfs_get_blocks( int nimaps = 1; xfs_off_t offset; ssize_t size; - int new = 0; - bool is_cow = false; - BUG_ON(create && !direct); + BUG_ON(create); if (XFS_FORCED_SHUTDOWN(mp)) return -EIO; @@ -1321,7 +1236,7 @@ __xfs_get_blocks( ASSERT(bh_result->b_size >= (1 << inode->i_blkbits)); size = bh_result->b_size; - if (!create && offset >= i_size_read(inode)) + if (offset >= i_size_read(inode)) return 0; /* @@ -1336,73 +1251,12 @@ __xfs_get_blocks( 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); - ASSERT(!is_cow || !isnullstartblock(imap.br_startblock)); - } - - 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); - } + error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb, + &imap, &nimaps, XFS_BMAPI_ENTIRE); 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) { + if (nimaps) { trace_xfs_get_blocks_found(ip, offset, size, ISUNWRITTEN(&imap) ? XFS_IO_UNWRITTEN : XFS_IO_OVERWRITE, &imap); @@ -1412,12 +1266,6 @@ __xfs_get_blocks( 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); @@ -1427,43 +1275,14 @@ __xfs_get_blocks( */ if (imap.br_startblock != HOLESTARTBLOCK && imap.br_startblock != DELAYSTARTBLOCK && - (create || !ISUNWRITTEN(&imap))) { - if (create && direct && !is_cow) { - error = xfs_bounce_unaligned_dio_write(ip, offset_fsb, - &imap); - if (error) - return error; - } - + !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) - 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: @@ -1471,100 +1290,6 @@ __xfs_get_blocks( return error; } -int -xfs_get_blocks( - struct inode *inode, - sector_t iblock, - struct buffer_head *bh_result, - int create) -{ - return __xfs_get_blocks(inode, iblock, bh_result, create, false); -} - -int -xfs_get_blocks_direct( - struct inode *inode, - sector_t iblock, - struct buffer_head *bh_result, - int create) -{ - return __xfs_get_blocks(inode, iblock, bh_result, create, true); -} - -/* - * 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, diff --git a/fs/xfs/xfs_aops.h b/fs/xfs/xfs_aops.h index 34dc00d..cc174ec 100644 --- a/fs/xfs/xfs_aops.h +++ b/fs/xfs/xfs_aops.h @@ -55,12 +55,6 @@ struct xfs_ioend { extern const struct address_space_operations xfs_address_space_operations; -int xfs_get_blocks(struct inode *inode, sector_t offset, - struct buffer_head *map_bh, int create); -int xfs_get_blocks_direct(struct inode *inode, sector_t offset, - struct buffer_head *map_bh, int create); -int xfs_end_io_direct_write(struct kiocb *iocb, loff_t offset, - ssize_t size, void *private); int xfs_setfilesize(struct xfs_inode *ip, xfs_off_t offset, size_t size); extern void xfs_count_page_state(struct page *, int *, int *); diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c index d054b73..f5effa6 100644 --- a/fs/xfs/xfs_file.c +++ b/fs/xfs/xfs_file.c @@ -210,62 +210,21 @@ xfs_file_dio_aio_read( struct kiocb *iocb, struct iov_iter *to) { - struct address_space *mapping = iocb->ki_filp->f_mapping; - struct inode *inode = mapping->host; - struct xfs_inode *ip = XFS_I(inode); - loff_t isize = i_size_read(inode); + struct xfs_inode *ip = XFS_I(file_inode(iocb->ki_filp)); size_t count = iov_iter_count(to); - loff_t end = iocb->ki_pos + count - 1; - struct iov_iter data; - struct xfs_buftarg *target; - ssize_t ret = 0; + ssize_t ret; trace_xfs_file_direct_read(ip, count, iocb->ki_pos); if (!count) return 0; /* skip atime */ - if (XFS_IS_REALTIME_INODE(ip)) - target = ip->i_mount->m_rtdev_targp; - else - target = ip->i_mount->m_ddev_targp; - - /* DIO must be aligned to device logical sector size */ - if ((iocb->ki_pos | count) & target->bt_logical_sectormask) { - if (iocb->ki_pos == isize) - return 0; - return -EINVAL; - } - file_accessed(iocb->ki_filp); xfs_ilock(ip, XFS_IOLOCK_SHARED); - if (mapping->nrpages) { - ret = filemap_write_and_wait_range(mapping, iocb->ki_pos, end); - if (ret) - goto out_unlock; - - /* - * Invalidate whole pages. This can return an error if we fail - * to invalidate a page, but this should never happen on XFS. - * Warn if it does fail. - */ - ret = invalidate_inode_pages2_range(mapping, - iocb->ki_pos >> PAGE_SHIFT, end >> PAGE_SHIFT); - WARN_ON_ONCE(ret); - ret = 0; - } - - data = *to; - ret = __blockdev_direct_IO(iocb, inode, target->bt_bdev, &data, - xfs_get_blocks_direct, NULL, NULL, 0); - if (ret >= 0) { - iocb->ki_pos += ret; - iov_iter_advance(to, ret); - } - -out_unlock: + ret = iomap_dio_rw(iocb, to, &xfs_iomap_ops, NULL); xfs_iunlock(ip, XFS_IOLOCK_SHARED); + return ret; } @@ -465,6 +424,58 @@ xfs_file_aio_write_checks( return 0; } +static int +xfs_dio_write_end_io( + struct kiocb *iocb, + ssize_t size, + unsigned flags) +{ + struct inode *inode = file_inode(iocb->ki_filp); + struct xfs_inode *ip = XFS_I(inode); + loff_t offset = iocb->ki_pos; + bool update_size = false; + 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; + + /* + * 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); + update_size = true; + } + spin_unlock(&ip->i_flags_lock); + + if (flags & IOMAP_DIO_COW) { + error = xfs_reflink_end_cow(ip, offset, size); + if (error) + return error; + } + + if (flags & IOMAP_DIO_UNWRITTEN) + error = xfs_iomap_write_unwritten(ip, offset, size); + else if (update_size) + error = xfs_setfilesize(ip, offset, size); + + return error; +} + /* * xfs_file_dio_aio_write - handle direct IO writes * @@ -504,9 +515,7 @@ xfs_file_dio_aio_write( int unaligned_io = 0; int iolock; size_t count = iov_iter_count(from); - loff_t end; - struct iov_iter data; - struct xfs_buftarg *target = XFS_IS_REALTIME_INODE(ip) ? + struct xfs_buftarg *target = XFS_IS_REALTIME_INODE(ip) ? mp->m_rtdev_targp : mp->m_ddev_targp; /* DIO must be aligned to device logical sector size */ @@ -534,23 +543,6 @@ xfs_file_dio_aio_write( if (ret) goto out; count = iov_iter_count(from); - end = iocb->ki_pos + count - 1; - - if (mapping->nrpages) { - ret = filemap_write_and_wait_range(mapping, iocb->ki_pos, end); - if (ret) - goto out; - - /* - * Invalidate whole pages. This can return an error if we fail - * to invalidate a page, but this should never happen on XFS. - * Warn if it does fail. - */ - ret = invalidate_inode_pages2_range(mapping, - iocb->ki_pos >> PAGE_SHIFT, end >> PAGE_SHIFT); - WARN_ON_ONCE(ret); - ret = 0; - } /* * If we are doing unaligned IO, wait for all other IO to drain, @@ -573,22 +565,7 @@ xfs_file_dio_aio_write( goto out; } - data = *from; - ret = __blockdev_direct_IO(iocb, inode, target->bt_bdev, &data, - xfs_get_blocks_direct, xfs_end_io_direct_write, - NULL, DIO_ASYNC_EXTEND); - - /* see generic_file_direct_write() for why this is necessary */ - if (mapping->nrpages) { - invalidate_inode_pages2_range(mapping, - iocb->ki_pos >> PAGE_SHIFT, - end >> PAGE_SHIFT); - } - - if (ret > 0) { - iocb->ki_pos += ret; - iov_iter_advance(from, ret); - } + ret = iomap_dio_rw(iocb, from, &xfs_iomap_ops, xfs_dio_write_end_io); out: xfs_iunlock(ip, iolock); @@ -1468,15 +1445,9 @@ xfs_filemap_fault( return xfs_filemap_page_mkwrite(vma, vmf); xfs_ilock(XFS_I(inode), XFS_MMAPLOCK_SHARED); - if (IS_DAX(inode)) { - /* - * we do not want to trigger unwritten extent conversion on read - * faults - that is unnecessary overhead and would also require - * changes to xfs_get_blocks_direct() to map unwritten extent - * ioend for conversion on read-only mappings. - */ + if (IS_DAX(inode)) ret = dax_iomap_fault(vma, vmf, &xfs_iomap_ops); - } else + else ret = filemap_fault(vma, vmf); xfs_iunlock(XFS_I(inode), XFS_MMAPLOCK_SHARED); diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c index 15a83813..0d14742 100644 --- a/fs/xfs/xfs_iomap.c +++ b/fs/xfs/xfs_iomap.c @@ -950,6 +950,19 @@ static inline bool imap_needs_alloc(struct inode *inode, (IS_DAX(inode) && ISUNWRITTEN(imap)); } +static inline bool need_excl_ilock(struct xfs_inode *ip, unsigned flags) +{ + /* + * COW writes will allocate delalloc space, so we need to make sure + * to take the lock exclusively here. + */ + if (xfs_is_reflink_inode(ip) && (flags & (IOMAP_WRITE | IOMAP_ZERO))) + return true; + if ((flags & IOMAP_DIRECT) && (flags & IOMAP_WRITE)) + return true; + return false; +} + static int xfs_file_iomap_begin( struct inode *inode, @@ -969,18 +982,14 @@ xfs_file_iomap_begin( if (XFS_FORCED_SHUTDOWN(mp)) return -EIO; - if ((flags & IOMAP_WRITE) && !IS_DAX(inode) && - !xfs_get_extsz_hint(ip)) { + if (((flags & (IOMAP_WRITE | IOMAP_DIRECT)) == IOMAP_WRITE) && + !IS_DAX(inode) && !xfs_get_extsz_hint(ip)) { /* Reserve delalloc blocks for regular writeback. */ return xfs_file_iomap_begin_delay(inode, offset, length, flags, iomap); } - /* - * COW writes will allocate delalloc space, so we need to make sure - * to take the lock exclusively here. - */ - if ((flags & (IOMAP_WRITE | IOMAP_ZERO)) && xfs_is_reflink_inode(ip)) { + if (need_excl_ilock(ip, flags)) { lockmode = XFS_ILOCK_EXCL; xfs_ilock(ip, XFS_ILOCK_EXCL); } else { @@ -993,17 +1002,41 @@ xfs_file_iomap_begin( offset_fsb = XFS_B_TO_FSBT(mp, offset); end_fsb = XFS_B_TO_FSB(mp, offset + length); + if (xfs_is_reflink_inode(ip) && + (flags & IOMAP_WRITE) && (flags & IOMAP_DIRECT)) { + shared = xfs_reflink_find_cow_mapping(ip, offset, &imap); + if (shared) { + xfs_iunlock(ip, lockmode); + goto alloc_done; + } + ASSERT(!isnullstartblock(imap.br_startblock)); + } + error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb, &imap, &nimaps, 0); if (error) goto out_unlock; - if (flags & IOMAP_REPORT) { + if ((flags & IOMAP_REPORT) || + (xfs_is_reflink_inode(ip) && + (flags & IOMAP_WRITE) && (flags & IOMAP_DIRECT))) { /* Trim the mapping to the nearest shared extent boundary. */ error = xfs_reflink_trim_around_shared(ip, &imap, &shared, &trimmed); if (error) goto out_unlock; + + /* + * We're here because we're trying to do a directio write to a + * region that isn't aligned to a filesystem block. If the + * extent is shared, fall back to buffered mode to handle the + * RMW. + */ + if (!(flags & IOMAP_REPORT) && shared) { + trace_xfs_reflink_bounce_dio_write(ip, &imap); + error = -EREMCHG; + goto out_unlock; + } } if ((flags & (IOMAP_WRITE | IOMAP_ZERO)) && xfs_is_reflink_inode(ip)) { @@ -1038,6 +1071,7 @@ xfs_file_iomap_begin( if (error) return error; +alloc_done: iomap->flags = IOMAP_F_NEW; trace_xfs_iomap_alloc(ip, offset, length, 0, &imap); } else {