From 8dfee37230ba3eafbeb9ff8cc28f0f8a32f3eec8 Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Thu, 26 Jun 2014 12:30:54 -0400 Subject: [PATCH] ext4: Fix hole punching for files with indirect blocks 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: bee871a23a29ee8aacb012f2c33cc7b752ec61ad Signed-off-by: Jan Kara Signed-off-by: Theodore Ts'o --- 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 6f3bb55567b63..fd69da1948265 100644 --- a/fs/ext4/indirect.c +++ b/fs/ext4/indirect.c @@ -1316,16 +1316,24 @@ 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); -- 2.39.5