From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wi0-f170.google.com ([209.85.212.170]:46688 "EHLO mail-wi0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753385AbaBOP4J (ORCPT ); Sat, 15 Feb 2014 10:56:09 -0500 Received: by mail-wi0-f170.google.com with SMTP id hi5so1268633wib.3 for ; Sat, 15 Feb 2014 07:56:08 -0800 (PST) From: Filipe David Borba Manana To: linux-btrfs@vger.kernel.org Cc: Filipe David Borba Manana Subject: [PATCH] Btrfs: don't insert useless holes when punching beyond the inode's size Date: Sat, 15 Feb 2014 15:55:58 +0000 Message-Id: <1392479758-9108-1-git-send-email-fdmanana@gmail.com> Sender: linux-btrfs-owner@vger.kernel.org List-ID: If we punch beyond the size of an inode, we'll correctly remove any prealloc extents, but we'll also insert file extent items representing holes (disk bytenr == 0) that start with a key offset that lies beyond the inode's size and are not contiguous with the last file extent item. Example: $XFS_IO_PROG -f -c "truncate 118811" $SCRATCH_MNT/foo $XFS_IO_PROG -c "fpunch 582007 864596" $SCRATCH_MNT/foo $XFS_IO_PROG -c "pwrite -S 0x0d -b 39987 92267 39987" $SCRATCH_MNT/foo btrfs-debug-tree output: item 4 key (257 INODE_ITEM 0) itemoff 15885 itemsize 160 inode generation 6 transid 6 size 132254 block group 0 mode 100600 links 1 item 5 key (257 INODE_REF 256) itemoff 15872 itemsize 13 inode ref index 2 namelen 3 name: foo item 6 key (257 EXTENT_DATA 0) itemoff 15819 itemsize 53 extent data disk byte 0 nr 0 gen 6 extent data offset 0 nr 90112 ram 122880 extent compression 0 item 7 key (257 EXTENT_DATA 90112) itemoff 15766 itemsize 53 extent data disk byte 12845056 nr 4096 gen 6 extent data offset 0 nr 45056 ram 45056 extent compression 2 item 8 key (257 EXTENT_DATA 585728) itemoff 15713 itemsize 53 extent data disk byte 0 nr 0 gen 6 extent data offset 0 nr 860160 ram 860160 extent compression 0 The last extent item, which represents a hole, is useless as it lies beyond the inode's size. Signed-off-by: Filipe David Borba Manana --- fs/btrfs/file.c | 28 +++++++++++++++++----------- 1 file changed, 17 insertions(+), 11 deletions(-) diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c index 006af2f..5133d71 100644 --- a/fs/btrfs/file.c +++ b/fs/btrfs/file.c @@ -2165,6 +2165,7 @@ static int btrfs_punch_hole(struct inode *inode, loff_t offset, loff_t len) bool same_page = ((offset >> PAGE_CACHE_SHIFT) == ((offset + len - 1) >> PAGE_CACHE_SHIFT)); bool no_holes = btrfs_fs_incompat(root->fs_info, NO_HOLES); + u64 ino_size = round_up(inode->i_size, PAGE_CACHE_SIZE); ret = btrfs_wait_ordered_range(inode, offset, len); if (ret) @@ -2180,14 +2181,14 @@ static int btrfs_punch_hole(struct inode *inode, loff_t offset, loff_t len) * entire page. */ if (same_page && len < PAGE_CACHE_SIZE) { - if (offset < round_up(inode->i_size, PAGE_CACHE_SIZE)) + if (offset < ino_size) ret = btrfs_truncate_page(inode, offset, len, 0); mutex_unlock(&inode->i_mutex); return ret; } /* zero back part of the first page */ - if (offset < round_up(inode->i_size, PAGE_CACHE_SIZE)) { + if (offset < ino_size) { ret = btrfs_truncate_page(inode, offset, 0, 0); if (ret) { mutex_unlock(&inode->i_mutex); @@ -2196,7 +2197,7 @@ static int btrfs_punch_hole(struct inode *inode, loff_t offset, loff_t len) } /* zero the front end of the last page */ - if (offset + len < round_up(inode->i_size, PAGE_CACHE_SIZE)) { + if (offset + len < ino_size) { ret = btrfs_truncate_page(inode, offset + len, 0, 1); if (ret) { mutex_unlock(&inode->i_mutex); @@ -2285,10 +2286,13 @@ static int btrfs_punch_hole(struct inode *inode, loff_t offset, loff_t len) trans->block_rsv = &root->fs_info->trans_block_rsv; - ret = fill_holes(trans, inode, path, cur_offset, drop_end); - if (ret) { - err = ret; - break; + if (cur_offset < ino_size) { + ret = fill_holes(trans, inode, path, cur_offset, + drop_end); + if (ret) { + err = ret; + break; + } } cur_offset = drop_end; @@ -2321,10 +2325,12 @@ static int btrfs_punch_hole(struct inode *inode, loff_t offset, loff_t len) } trans->block_rsv = &root->fs_info->trans_block_rsv; - ret = fill_holes(trans, inode, path, cur_offset, drop_end); - if (ret) { - err = ret; - goto out_trans; + if (cur_offset < ino_size) { + ret = fill_holes(trans, inode, path, cur_offset, drop_end); + if (ret) { + err = ret; + goto out_trans; + } } out_trans: -- 1.7.9.5