From: Christoph Hellwig <hch@lst.de> To: Goldwyn Rodrigues <rgoldwyn@suse.com>, linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: [PATCH 06/19] iomap: use write_begin to read pages to unshare Date: Mon, 9 Sep 2019 20:27:09 +0200 Message-ID: <20190909182722.16783-7-hch@lst.de> (raw) In-Reply-To: <20190909182722.16783-1-hch@lst.de> Use the existing iomap write_begin code to read the pages unshared by iomap_file_unshare. That avoids the extra ->readpage call and extent tree lookup currently done by read_mapping_page. Signed-off-by: Christoph Hellwig <hch@lst.de> --- fs/iomap/buffered-io.c | 49 ++++++++++++++---------------------------- 1 file changed, 16 insertions(+), 33 deletions(-) diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c index fe099faf540f..a421977a9496 100644 --- a/fs/iomap/buffered-io.c +++ b/fs/iomap/buffered-io.c @@ -533,6 +533,10 @@ iomap_migrate_page(struct address_space *mapping, struct page *newpage, EXPORT_SYMBOL_GPL(iomap_migrate_page); #endif /* CONFIG_MIGRATION */ +enum { + IOMAP_WRITE_F_UNSHARE = (1 << 0), +}; + static void iomap_write_failed(struct inode *inode, loff_t pos, unsigned len) { @@ -562,7 +566,7 @@ iomap_read_page_sync(loff_t block_start, struct page *page, unsigned poff, } static int -__iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, +__iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, int flags, struct page *page, struct iomap *iomap) { struct iomap_page *iop = iomap_page_create(inode, page); @@ -581,11 +585,14 @@ __iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, if (plen == 0) break; - if ((from <= poff || from >= poff + plen) && + if (!(flags & IOMAP_WRITE_F_UNSHARE) && + (from <= poff || from >= poff + plen) && (to <= poff || to >= poff + plen)) continue; if (iomap_block_needs_zeroing(inode, iomap, block_start)) { + if (WARN_ON_ONCE(flags & IOMAP_WRITE_F_UNSHARE)) + return -EIO; zero_user_segments(page, poff, from, to, poff + plen); iomap_set_range_uptodate(page, poff, plen); continue; @@ -631,7 +638,8 @@ iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, unsigned flags, else if (iomap->flags & IOMAP_F_BUFFER_HEAD) status = __block_write_begin_int(page, pos, len, NULL, iomap); else - status = __iomap_write_begin(inode, pos, len, page, iomap); + status = __iomap_write_begin(inode, pos, len, flags, page, + iomap); if (unlikely(status)) goto out_unlock; @@ -854,22 +862,6 @@ iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *iter, } EXPORT_SYMBOL_GPL(iomap_file_buffered_write); -static struct page * -__iomap_read_page(struct inode *inode, loff_t offset) -{ - struct address_space *mapping = inode->i_mapping; - struct page *page; - - page = read_mapping_page(mapping, offset >> PAGE_SHIFT, NULL); - if (IS_ERR(page)) - return page; - if (!PageUptodate(page)) { - put_page(page); - return ERR_PTR(-EIO); - } - return page; -} - static loff_t iomap_unshare_actor(struct inode *inode, loff_t pos, loff_t length, void *data, struct iomap *iomap) @@ -885,24 +877,15 @@ iomap_unshare_actor(struct inode *inode, loff_t pos, loff_t length, void *data, return length; do { - struct page *page, *rpage; - unsigned long offset; /* Offset into pagecache page */ - unsigned long bytes; /* Bytes to write to page */ - - offset = offset_in_page(pos); - bytes = min_t(loff_t, PAGE_SIZE - offset, length); - - rpage = __iomap_read_page(inode, pos); - if (IS_ERR(rpage)) - return PTR_ERR(rpage); + unsigned long offset = offset_in_page(pos); + unsigned long bytes = min_t(loff_t, PAGE_SIZE - offset, length); + struct page *page; - status = iomap_write_begin(inode, pos, bytes, 0, &page, iomap); - put_page(rpage); + status = iomap_write_begin(inode, pos, bytes, + IOMAP_WRITE_F_UNSHARE, &page, iomap); if (unlikely(status)) return status; - WARN_ON_ONCE(!PageUptodate(page)); - status = iomap_write_end(inode, pos, bytes, bytes, page, iomap); if (unlikely(status <= 0)) { if (WARN_ON_ONCE(status == 0)) -- 2.20.1
next prev parent reply index Thread overview: 54+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-09-09 18:27 iomap and xfs COW cleanups Christoph Hellwig 2019-09-09 18:27 ` [PATCH 01/19] iomap: better document the IOMAP_F_* flags Christoph Hellwig 2019-09-14 0:42 ` Allison Collins 2019-09-16 18:08 ` Darrick J. Wong 2019-09-09 18:27 ` [PATCH 02/19] iomap: remove the unused iomap argument to __iomap_write_end Christoph Hellwig 2019-09-14 0:42 ` Allison Collins 2019-09-16 18:10 ` Darrick J. Wong 2019-09-09 18:27 ` [PATCH 03/19] iomap: always use AOP_FLAG_NOFS in iomap_write_begin Christoph Hellwig 2019-09-16 18:11 ` Darrick J. Wong 2019-09-09 18:27 ` [PATCH 04/19] iomap: ignore non-shared or non-data blocks in xfs_file_dirty Christoph Hellwig 2019-09-16 18:12 ` Darrick J. Wong 2019-09-09 18:27 ` [PATCH 05/19] iomap: move the zeroing case out of iomap_read_page_sync Christoph Hellwig 2019-09-16 18:17 ` Darrick J. Wong 2019-09-09 18:27 ` Christoph Hellwig [this message] 2019-09-16 18:34 ` [PATCH 06/19] iomap: use write_begin to read pages to unshare Darrick J. Wong 2019-09-30 11:07 ` Christoph Hellwig 2019-10-08 15:12 ` Darrick J. Wong 2019-09-09 18:27 ` [PATCH 07/19] iomap: use a srcmap for a read-modify-write I/O Christoph Hellwig 2019-09-10 12:48 ` Goldwyn Rodrigues 2019-09-10 14:39 ` hch 2019-09-16 17:57 ` Darrick J. Wong 2019-09-16 18:42 ` Darrick J. Wong 2019-09-18 18:15 ` Darrick J. Wong 2019-09-09 18:27 ` [PATCH 08/19] xfs: also call xfs_file_iomap_end_delalloc for zeroing operations Christoph Hellwig 2019-09-18 17:09 ` Darrick J. Wong 2019-09-09 18:27 ` [PATCH 09/19] xfs: remove xfs_reflink_dirty_extents Christoph Hellwig 2019-09-18 17:17 ` Darrick J. Wong 2019-09-18 17:25 ` Christoph Hellwig 2019-09-18 17:31 ` Darrick J. Wong 2019-09-09 18:27 ` [PATCH 10/19] xfs: pass two imaps to xfs_reflink_allocate_cow Christoph Hellwig 2019-09-18 17:26 ` Darrick J. Wong 2019-09-30 11:10 ` Christoph Hellwig 2019-09-09 18:27 ` [PATCH 11/19] xfs: refactor xfs_file_iomap_begin_delay Christoph Hellwig 2019-09-18 17:30 ` Darrick J. Wong 2019-09-09 18:27 ` [PATCH 12/19] xfs: fill out the srcmap in iomap_begin Christoph Hellwig 2019-09-18 17:52 ` Darrick J. Wong 2019-10-01 6:26 ` Christoph Hellwig 2019-09-09 18:27 ` [PATCH 13/19] xfs: factor out a helper to calculate the end_fsb Christoph Hellwig 2019-09-14 0:42 ` Allison Collins 2019-09-18 17:55 ` Darrick J. Wong 2019-09-09 18:27 ` [PATCH 14/19] xfs: split out a new set of read-only iomap ops Christoph Hellwig 2019-09-18 17:56 ` Darrick J. Wong 2019-09-09 18:27 ` [PATCH 15/19] xfs: move xfs_file_iomap_begin_delay around Christoph Hellwig 2019-09-18 17:59 ` Darrick J. Wong 2019-09-30 11:14 ` Christoph Hellwig 2019-09-09 18:27 ` [PATCH 16/19] xfs: split the iomap ops for buffered vs direct writes Christoph Hellwig 2019-09-18 18:00 ` Darrick J. Wong 2019-09-09 18:27 ` [PATCH 17/19] xfs: rename the whichfork variable in xfs_buffered_write_iomap_begin Christoph Hellwig 2019-09-14 0:42 ` Allison Collins 2019-09-18 18:00 ` Darrick J. Wong 2019-09-09 18:27 ` [PATCH 18/19] xfs: cleanup xfs_iomap_write_unwritten Christoph Hellwig 2019-09-18 18:06 ` Darrick J. Wong 2019-09-09 18:27 ` [PATCH 19/19] xfs: improve the IOMAP_NOWAIT check for COW inodes Christoph Hellwig 2019-09-18 18:09 ` Darrick J. Wong
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