On Fri, Aug 15, 2008 at 05:38:33PM -0700, Mingming Cao wrote:
>
> Ext4: journal credits reservation fixes for extent file writepage
>
> From: Mingming Cao <cmm@xxxxxxxxxx>
>
> This patch modified the writepage/write_begin credit caculation for
> extent files, to use the credits caculation helper function.
>
> The current calculation of how many index/leaf blocks should be
> accounted is too conservetive, it always consider the worse case, where
> the tree level is 5, and in the case of multiple chunk allocation, it
> always multiple the needed credits. This path uses the accurate depth of
> the inode with some extras to caluate the index blocks, and also less
> conservetive in the case of multiple allocation accounting.
>
> Signed-off-by: Mingming Cao <cmm@xxxxxxxxxx>
> ---
> ---
> fs/ext4/ext4_extents.h | 3 +
> fs/ext4/extents.c | 88 ++++++++++++++++---------------------------------
> fs/ext4/migrate.c | 3 +
> 3 files changed, 34 insertions(+), 60 deletions(-)
>
> Index: linux-2.6.27-rc3/fs/ext4/ext4_extents.h
> ===================================================================
> --- linux-2.6.27-rc3.orig/fs/ext4/ext4_extents.h 2008-08-15 14:43:20.000000000 -0700
> +++ linux-2.6.27-rc3/fs/ext4/ext4_extents.h 2008-08-15 14:44:15.000000000 -0700
> @@ -216,7 +216,9 @@ extern int ext4_ext_calc_metadata_amount
> extern ext4_fsblk_t idx_pblock(struct ext4_extent_idx *);
> extern void ext4_ext_store_pblock(struct ext4_extent *, ext4_fsblk_t);
> extern int ext4_extent_tree_init(handle_t *, struct inode *);
> -extern int ext4_ext_calc_credits_for_insert(struct inode *, struct ext4_ext_path *);
> +extern int ext4_ext_calc_credits_for_single_extent(struct inode *inode,
> + int num,
> + struct ext4_ext_path *path);
> extern int ext4_ext_try_to_merge(struct inode *inode,
> struct ext4_ext_path *path,
> struct ext4_extent *);
> Index: linux-2.6.27-rc3/fs/ext4/extents.c
> ===================================================================
> --- linux-2.6.27-rc3.orig/fs/ext4/extents.c 2008-08-15 14:43:20.000000000 -0700
> +++ linux-2.6.27-rc3/fs/ext4/extents.c 2008-08-15 14:51:07.000000000 -0700
> @@ -1747,54 +1747,62 @@ static int ext4_ext_rm_idx(handle_t *han
> }
>
> /*
> - * ext4_ext_calc_credits_for_insert:
> - * This routine returns max. credits that the extent tree can consume.
> - * It should be OK for low-performance paths like ->writepage()
> - * To allow many writing processes to fit into a single transaction,
> - * the caller should calculate credits under i_data_sem and
> - * pass the actual path.
> + * ext4_ext_calc_credits_for_single_extent:
> + * This routine returns max. credits that needed to insert an extent
> + * to the extent tree.
> + * When pass the actual path, the caller should calculate credits
> + * under i_data_sem.
> */
> -int ext4_ext_calc_credits_for_insert(struct inode *inode,
> +int ext4_ext_calc_credits_for_single_extent(struct inode *inode, int num,
> struct ext4_ext_path *path)
> {
s/num/nrblocks/
> - int depth, needed;
> -
> if (path) {
> + int depth = ext_depth(inode);
> + int ret;
> +
> /* probably there is space in leaf? */
> - depth = ext_depth(inode);
> if (le16_to_cpu(path[depth].p_hdr->eh_entries)
> - < le16_to_cpu(path[depth].p_hdr->eh_max))
> - return 1;
> - }
> -
> - /*
> - * given 32-bit logical block (4294967296 blocks), max. tree
> - * can be 4 levels in depth -- 4 * 340^4 == 53453440000.
> - * Let's also add one more level for imbalance.
> - */
> - depth = 5;
> + < le16_to_cpu(path[depth].p_hdr->eh_max)) {
>
> - /* allocation of new data block(s) */
> - needed = 2;
-aneesh
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