Hi. Eric.
This is the patch for punch hole issue.
Thanks.
2012/6/14, Ashish Sangwan <ashishsangwan2@xxxxxxxxx>:
> The current implementation of hole punch uses the same code path as for
> truncate in which the block removal starts from the end of the file and
> continue backwards removing extents and in the process decreases the
> count of valid entries in the extent header of extent index.
> If all the extents under current extent index are removed than this index
> is also removed and the number of valid entries in the "depth -1"
> extent header is decreased by 1.
>
> Whether to continue removing extents or not is decided by the return value
> of function ext4_ext_more_to_rm() which checks 2 conditions:
> a) if there are no more indexes to process.
> b) if the number of entries are decreased in the header of "depth -1".
>
> In case of hole punch, if the last block to be removed is not part of the
> last extent index than this index will not be deleted, hence the number of
> valid entries in the extent header of "depth - 1" will remain as it is and
> ext4_ext_more_to_rm will return 0 although the required blocks are not
> yet removed.
>
> This patch fixes the above mentioned problem as instead of removing the
> extents from the end of file, it starts removing the blocks from the
> particular extent from which removing blocks is actually required and
> continue backward until done.
>
> Signed-off-by: Ashish Sangwan <ashish.sangwan2@xxxxxxxxx>
> Signed-off-by: Namjae Jeon <linkinjeon@xxxxxxxxx>
> ---
> fs/ext4/extents.c | 43 +++++++++++++++++++++++++++----------------
> 1 files changed, 27 insertions(+), 16 deletions(-)
>
> diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
> index 91341ec..27c3a30 100644
> --- a/fs/ext4/extents.c
> +++ b/fs/ext4/extents.c
> @@ -2570,10 +2570,10 @@ static int ext4_ext_remove_space(struct inode
> *inode, ext4_lblk_t start,
> {
> struct super_block *sb = inode->i_sb;
> int depth = ext_depth(inode);
> - struct ext4_ext_path *path;
> + struct ext4_ext_path *path = NULL;
> ext4_fsblk_t partial_cluster = 0;
> handle_t *handle;
> - int i, err;
> + int i = 0, err;
>
> ext_debug("truncate since %u to %u\n", start, end);
>
> @@ -2606,8 +2606,12 @@ again:
> }
> depth = ext_depth(inode);
> ex = path[depth].p_ext;
> - if (!ex)
> + if (!ex) {
> + ext4_ext_drop_refs(path);
> + kfree(path);
> + path = NULL;
> goto cont;
> + }
>
> ee_block = le32_to_cpu(ex->ee_block);
>
> @@ -2637,8 +2641,6 @@ again:
> if (err < 0)
> goto out;
> }
> - ext4_ext_drop_refs(path);
> - kfree(path);
> }
> cont:
>
> @@ -2647,19 +2649,27 @@ cont:
> * after i_size and walking into the tree depth-wise.
> */
> depth = ext_depth(inode);
> - path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 1), GFP_NOFS);
> - if (path == NULL) {
> - ext4_journal_stop(handle);
> - return -ENOMEM;
> - }
> - path[0].p_depth = depth;
> - path[0].p_hdr = ext_inode_hdr(inode);
> + if (path) {
> + int k = i = depth;
> + while (--k >= 0)
> + path[k].p_block =
> + le16_to_cpu(path[k].p_hdr->eh_entries)+1;
> + } else {
> + path =
> + kzalloc(sizeof(struct ext4_ext_path) * (depth + 1), GFP_NOFS);
> + if (path == NULL) {
> + ext4_journal_stop(handle);
> + return -ENOMEM;
> + }
> + path[0].p_depth = depth;
> + path[0].p_hdr = ext_inode_hdr(inode);
>
> - if (ext4_ext_check(inode, path[0].p_hdr, depth)) {
> - err = -EIO;
> - goto out;
> + if (ext4_ext_check(inode, path[0].p_hdr, depth)) {
> + err = -EIO;
> + goto out;
> + }
> }
> - i = err = 0;
> + err = 0;
>
> while (i >= 0 && err == 0) {
> if (i == depth) {
> @@ -2773,6 +2783,7 @@ cont:
> out:
> ext4_ext_drop_refs(path);
> kfree(path);
> + path = NULL;
> if (err == -EAGAIN)
> goto again;
> ext4_journal_stop(handle);
> --
> 1.7.2.3
>
>
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