Re: [PATCH 10/31] libext2fs: Allow callers to punch a single block

jon ernst
2013-10-01T19:09:45Z

On Mon, Sep 30, 2013 at 9:27 PM, Darrick J. Wong
<darrick.wong@oracle.com> wrote:
> The range of blocks to punch is treated as an inclusive range on both ends,
> i.e. if start=1 and end=2, both blocks 1 and 2 are punched out. Thus, start ==
> end means that the caller wishes to punch a single block. Remove the check
> that prevents us from punching a single block.
>
> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> ---
> lib/ext2fs/ext2fs.h | 4 ++++
> lib/ext2fs/punch.c | 5 +----
> 2 files changed, 5 insertions(+), 4 deletions(-)
>
>
> diff --git a/lib/ext2fs/ext2fs.h b/lib/ext2fs/ext2fs.h
> index 311ceda..c37e00b 100644
> --- a/lib/ext2fs/ext2fs.h
> +++ b/lib/ext2fs/ext2fs.h
> @@ -1385,6 +1385,10 @@ extern errcode_t ext2fs_check_mount_point(const char *device, int *mount_flags,
> char *mtpt, int mtlen);
>
> /* punch.c */
> +/*
> + * NOTE: This function removes from an inode the blocks "start", "end", and
> + * every block in between.
> + */
> extern errcode_t ext2fs_punch(ext2_filsys fs, ext2_ino_t ino,
> struct ext2_inode *inode,
> char *block_buf, blk64_t start,
> diff --git a/lib/ext2fs/punch.c b/lib/ext2fs/punch.c
> index 11c7668..aac1942 100644
> --- a/lib/ext2fs/punch.c
> +++ b/lib/ext2fs/punch.c
> @@ -315,9 +315,6 @@ extern errcode_t ext2fs_punch(ext2_filsys fs, ext2_ino_t ino,
> if (start > end)
> return EINVAL;
>
> - if (start == end)
> - return 0;
> -
> /* Read inode structure if necessary */
> if (!inode) {
> retval = ext2fs_read_inode(fs, ino, &inode_buf);
> @@ -332,7 +329,7 @@ extern errcode_t ext2fs_punch(ext2_filsys fs, ext2_ino_t ino,
>
> if (start > ~0U)
> return 0;
> - count = ((end - start) < ~0U) ? (end - start) : ~0U;
> + count = ((end - start + 1) < ~0U) ? (end - start + 1) : ~0U;
can you simply put "count = end - start + 1;" since you have checked
start > end case earlier.
> retval = ext2fs_punch_ind(fs, inode, block_buf,
> (blk_t) start, count);
> }
>
> --
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