> On Aug 24, 2016, at 13:27, Benjamin Coddington <bcodding@xxxxxxxxxx> wrote:
>
> Commit 311324ad1713666a6e803aecf0d4e1a136a5b34a ("NFS: Be more aggressive
> in using readdirplus for 'ls -l' situations") removed the optimization
> added by commit 07b5ce8ef2d87f1914054804720d6facbaa3f4ce ("NFS: Make nfs_readdir
> revalidate less often") to bypass the revalidation of the directory mapping
> on subsequent calls into nfs_readdir(). Add that optimization back here.
>
> A directory modified once every second and containing 40k entries takes my
> system around 80 seconds to list. With this patch, that time is reduced to
> 7 seconds.
>
> Signed-off-by: Benjamin Coddington <bcodding@xxxxxxxxxx>
> ---
> fs/nfs/dir.c | 13 +------------
> 1 file changed, 1 insertion(+), 12 deletions(-)
>
> diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
> index 19d93d0cd400..9a036dc6caa3 100644
> --- a/fs/nfs/dir.c
> +++ b/fs/nfs/dir.c
> @@ -872,17 +872,6 @@ int uncached_readdir(nfs_readdir_descriptor_t *desc)
> goto out;
> }
>
> -static bool nfs_dir_mapping_need_revalidate(struct inode *dir)
> -{
> - struct nfs_inode *nfsi = NFS_I(dir);
> -
> - if (nfs_attribute_cache_expired(dir))
> - return true;
> - if (nfsi->cache_validity & NFS_INO_INVALID_DATA)
> - return true;
> - return false;
> -}
> -
> /* The file offset position represents the dirent entry number. A
> last cookie cache takes care of the common case of reading the
> whole directory.
> @@ -914,7 +903,7 @@ static int nfs_readdir(struct file *file, struct dir_context *ctx)
> desc->decode = NFS_PROTO(inode)->decode_dirent;
> desc->plus = nfs_use_readdirplus(inode, ctx) ? 1 : 0;
>
> - if (ctx->pos == 0 || nfs_dir_mapping_need_revalidate(inode))
> + if (ctx->pos == 0 || nfs_attribute_cache_expired(inode))
> res = nfs_revalidate_mapping(inode, file->f_mapping);
> if (res < 0)
> goto out;
> --
> 2.5.5
>
NACK.
As already discussed, this patch will break the functionality introduced in commit 311324ad1713. You need at least to ensure that we respect nfs_force_use_readdirplus().
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