On Wed, Feb 26, 2020 at 03:27:06PM +0530, Ritesh Harjani wrote:
> For indirect block mapping if the i_block > max supported block in inode
> then ext4_ind_map_blocks may return a -EIO error. But in case of fiemap
> this could be a valid query to ext4_map_blocks.
> So in case if !create then return 0. This also makes ext4_warning to
> ext4_debug in ext4_block_to_path() for the same reason.
>
> Signed-off-by: Ritesh Harjani <riteshh@xxxxxxxxxxxxx>
> ---
> fs/ext4/indirect.c | 11 +++++++++--
> 1 file changed, 9 insertions(+), 2 deletions(-)
>
> diff --git a/fs/ext4/indirect.c b/fs/ext4/indirect.c
> index 3a4ab70fe9e0..e1ab495dd900 100644
> --- a/fs/ext4/indirect.c
> +++ b/fs/ext4/indirect.c
> @@ -102,7 +102,11 @@ static int ext4_block_to_path(struct inode *inode,
> offsets[n++] = i_block & (ptrs - 1);
> final = ptrs;
> } else {
> - ext4_warning(inode->i_sb, "block %lu > max in inode %lu",
> + /*
> + * It's not yet an error to just query beyond max
> + * block in inode. Fiemap callers may do so.
> + */
> + ext4_debug("block %lu > max in inode %lu",
> i_block + direct_blocks +
> indirect_blocks + double_blocks, inode->i_ino);
Does that mean fiemap callers can spamflood dmesg with this message just
by setting the query start range to a huge value?
--D
> }
> @@ -537,8 +541,11 @@ int ext4_ind_map_blocks(handle_t *handle, struct inode *inode,
> depth = ext4_block_to_path(inode, map->m_lblk, offsets,
> &blocks_to_boundary);
>
> - if (depth == 0)
> + if (depth == 0) {
> + if (!(flags & EXT4_GET_BLOCKS_CREATE))
> + err = 0;
> goto out;
> + }
>
> partial = ext4_get_branch(inode, depth, offsets, chain, &err);
>
> --
> 2.21.0
>
