btrfs: Return right extent when fiemap gives unaligned offset and len.

When page aligned start and len passed to extent_fiemap(), the result is
good, but when start and len is not aligned, e.g. start = 1 and len =
4095 is passed to extent_fiemap(), it returns no extent.

The problem is that start and len is all rounded down which causes the
problem. This patch will round down start and round up (start + len) to
return right extent.

Reported-by: Chandan Rajendra <chandan@linux.vnet.ibm.com>
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Reviewed-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <clm@fb.com>
This commit is contained in:
Qu Wenruo 2014-07-18 09:55:43 +08:00 committed by Chris Mason
parent e2eca69dc6
commit 2c91943b50

View File

@ -4213,8 +4213,8 @@ int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
return -ENOMEM;
path->leave_spinning = 1;
start = ALIGN(start, BTRFS_I(inode)->root->sectorsize);
len = ALIGN(len, BTRFS_I(inode)->root->sectorsize);
start = round_down(start, BTRFS_I(inode)->root->sectorsize);
len = round_up(max, BTRFS_I(inode)->root->sectorsize) - start;
/*
* lookup the last file extent. We're not using i_size here