From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Kara Subject: [PATCH 2/2] ext4: Fix hole punching for files with indirect blocks Date: Wed, 18 Jun 2014 21:33:04 +0200 Message-ID: <1403119984-3635-2-git-send-email-jack@suse.cz> References: <1403119984-3635-1-git-send-email-jack@suse.cz> Cc: linux-ext4@vger.kernel.org, Jan Kara , stable@vger.kernel.org To: Ted Tso Return-path: In-Reply-To: <1403119984-3635-1-git-send-email-jack@suse.cz> Sender: stable-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org Hole punching code for files with indirect blocks wrongly computed number of blocks which need to be cleared when traversing the indirect block tree. That could result in punching more blocks than actually requested and thus effectively cause a data loss. For example: fallocate -n -p 10240000 4096 will punch the range 10240000 - 12632064 instead of the range 1024000 - 10244096. Fix the calculation. CC: stable@vger.kernel.org Fixes: 8bad6fc813a3a5300f51369c39d315679fd88c72 Signed-off-by: Jan Kara --- fs/ext4/indirect.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/fs/ext4/indirect.c b/fs/ext4/indirect.c index 9d381707a6fc..771949c82715 100644 --- a/fs/ext4/indirect.c +++ b/fs/ext4/indirect.c @@ -1310,16 +1310,24 @@ static int free_hole_blocks(handle_t *handle, struct inode *inode, blk = *i_data; if (level > 0) { ext4_lblk_t first2; + ext4_lblk_t count2; + bh = sb_bread(inode->i_sb, le32_to_cpu(blk)); if (!bh) { EXT4_ERROR_INODE_BLOCK(inode, le32_to_cpu(blk), "Read failure"); return -EIO; } - first2 = (first > offset) ? first - offset : 0; + if (first > offset) { + first2 = first - offset; + count2 = count; + } else { + first2 = 0; + count2 = count - (offset - first); + } ret = free_hole_blocks(handle, inode, bh, (__le32 *)bh->b_data, level - 1, - first2, count - offset, + first2, count2, inode->i_sb->s_blocksize >> 2); if (ret) { brelse(bh); -- 1.8.1.4