2020-11-02 18:18:51

by Trond Myklebust

Subject: [PATCH 03/12] NFS: Clean up nfs_readdir_page_filler()

From: Trond Myklebust <[email protected]>

Clean up handling of the case where there are no entries in the readdir
reply.

Signed-off-by: Trond Myklebust <[email protected]>
---
fs/nfs/dir.c | 39 ++++++++++++++++++---------------------
1 file changed, 18 insertions(+), 21 deletions(-)

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index 604ebe015387..68acbde3f914 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -601,16 +601,12 @@ int nfs_readdir_page_filler(nfs_readdir_descriptor_t *desc, struct nfs_entry *en
struct xdr_stream stream;
struct xdr_buf buf;
struct page *scratch;
- unsigned int count = 0;
int status;

scratch = alloc_page(GFP_KERNEL);
if (scratch == NULL)
return -ENOMEM;

- if (buflen == 0)
- goto out_nopages;
-
xdr_init_decode_pages(&stream, &buf, xdr_pages, buflen);
xdr_set_scratch_buffer(&stream, page_address(scratch), PAGE_SIZE);

@@ -619,27 +615,27 @@ int nfs_readdir_page_filler(nfs_readdir_descriptor_t *desc, struct nfs_entry *en
entry->label->len = NFS4_MAXLABELLEN;

status = xdr_decode(desc, entry, &stream);
- if (status != 0) {
- if (status == -EAGAIN)
- status = 0;
+ if (status != 0)
break;
- }
-
- count++;

if (desc->plus)
nfs_prime_dcache(file_dentry(desc->file), entry,
desc->dir_verifier);

status = nfs_readdir_add_to_array(entry, page);
- if (status != 0)
- break;
- } while (!entry->eof);
+ } while (!status && !entry->eof);

-out_nopages:
- if (count == 0 || (status == -EBADCOOKIE && entry->eof != 0)) {
- nfs_readdir_page_set_eof(page);
+ switch (status) {
+ case -EBADCOOKIE:
+ if (entry->eof) {
+ nfs_readdir_page_set_eof(page);
+ status = 0;
+ }
+ break;
+ case -ENOSPC:
+ case -EAGAIN:
status = 0;
+ break;
}

put_page(scratch);
@@ -714,14 +710,15 @@ int nfs_readdir_xdr_to_array(nfs_readdir_descriptor_t *desc, struct page *page,

if (status < 0)
break;
+
pglen = status;
- status = nfs_readdir_page_filler(desc, &entry, pages, page, pglen);
- if (status < 0) {
- if (status == -ENOSPC)
- status = 0;
+ if (pglen == 0) {
+ nfs_readdir_page_set_eof(page);
break;
}
- } while (!nfs_readdir_array_is_full(array));
+
+ status = nfs_readdir_page_filler(desc, &entry, pages, page, pglen);
+ } while (!status && !nfs_readdir_array_is_full(array));

nfs_readdir_free_pages(pages, array_size);
out_release_array:
--
2.28.0

2020-11-03 14:21:20

by Benjamin Coddington

Subject: Re: [PATCH 03/12] NFS: Clean up nfs_readdir_page_filler()

On 2 Nov 2020, at 13:06, [email protected] wrote:

> From: Trond Myklebust <[email protected]>
>
> Clean up handling of the case where there are no entries in the
> readdir
> reply.
>
> Signed-off-by: Trond Myklebust <[email protected]>
> ---
> fs/nfs/dir.c | 39 ++++++++++++++++++---------------------
> 1 file changed, 18 insertions(+), 21 deletions(-)
>
> diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
> index 604ebe015387..68acbde3f914 100644
> --- a/fs/nfs/dir.c
> +++ b/fs/nfs/dir.c
> @@ -601,16 +601,12 @@ int
> nfs_readdir_page_filler(nfs_readdir_descriptor_t *desc, struct
> nfs_entry *en
> struct xdr_stream stream;
> struct xdr_buf buf;
> struct page *scratch;
> - unsigned int count = 0;
> int status;
>
> scratch = alloc_page(GFP_KERNEL);
> if (scratch == NULL)
> return -ENOMEM;
>
> - if (buflen == 0)
> - goto out_nopages;
> -
> xdr_init_decode_pages(&stream, &buf, xdr_pages, buflen);
> xdr_set_scratch_buffer(&stream, page_address(scratch), PAGE_SIZE);
>
> @@ -619,27 +615,27 @@ int
> nfs_readdir_page_filler(nfs_readdir_descriptor_t *desc, struct
> nfs_entry *en
> entry->label->len = NFS4_MAXLABELLEN;
>
> status = xdr_decode(desc, entry, &stream);
> - if (status != 0) {
> - if (status == -EAGAIN)
> - status = 0;
> + if (status != 0)
> break;
> - }
> -
> - count++;
>
> if (desc->plus)
> nfs_prime_dcache(file_dentry(desc->file), entry,
> desc->dir_verifier);
>
> status = nfs_readdir_add_to_array(entry, page);
> - if (status != 0)
> - break;
> - } while (!entry->eof);
> + } while (!status && !entry->eof);
>
> -out_nopages:
> - if (count == 0 || (status == -EBADCOOKIE && entry->eof != 0)) {
> - nfs_readdir_page_set_eof(page);
> + switch (status) {
> + case -EBADCOOKIE:
> + if (entry->eof) {
> + nfs_readdir_page_set_eof(page);
> + status = 0;
> + }
> + break;
> + case -ENOSPC:

If you return ENOSPC, then you don't need to use
nfs_readdir_array_is_full(array) below..

> + case -EAGAIN:
> status = 0;
> + break;
> }
>
> put_page(scratch);
> @@ -714,14 +710,15 @@ int
> nfs_readdir_xdr_to_array(nfs_readdir_descriptor_t *desc, struct page
> *page,
>
> if (status < 0)
> break;
> +
> pglen = status;
> - status = nfs_readdir_page_filler(desc, &entry, pages, page, pglen);
> - if (status < 0) {
> - if (status == -ENOSPC)
> - status = 0;
> + if (pglen == 0) {
> + nfs_readdir_page_set_eof(page);
> break;
> }
> - } while (!nfs_readdir_array_is_full(array));
> +
> + status = nfs_readdir_page_filler(desc, &entry, pages, page, pglen);
> + } while (!status && !nfs_readdir_array_is_full(array));

^^ here.

I suppose nfs_readdir_array_is_full() is nice and clear.. I wonder if
the
compiler would optimize it away.

Ben

2020-11-03 14:28:46

by Benjamin Coddington

Subject: Re: [PATCH 03/12] NFS: Clean up nfs_readdir_page_filler()

On 3 Nov 2020, at 9:18, Benjamin Coddington wrote:

> On 2 Nov 2020, at 13:06, [email protected] wrote:
>
>> From: Trond Myklebust <[email protected]>
>>
>> Clean up handling of the case where there are no entries in the
>> readdir
>> reply.
>>
>> Signed-off-by: Trond Myklebust <[email protected]>
>> ---
>> fs/nfs/dir.c | 39 ++++++++++++++++++---------------------
>> 1 file changed, 18 insertions(+), 21 deletions(-)
>>
>> diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
>> index 604ebe015387..68acbde3f914 100644
>> --- a/fs/nfs/dir.c
>> +++ b/fs/nfs/dir.c
>> @@ -601,16 +601,12 @@ int
>> nfs_readdir_page_filler(nfs_readdir_descriptor_t *desc, struct
>> nfs_entry *en
>> struct xdr_stream stream;
>> struct xdr_buf buf;
>> struct page *scratch;
>> - unsigned int count = 0;
>> int status;
>>
>> scratch = alloc_page(GFP_KERNEL);
>> if (scratch == NULL)
>> return -ENOMEM;
>>
>> - if (buflen == 0)
>> - goto out_nopages;
>> -
>> xdr_init_decode_pages(&stream, &buf, xdr_pages, buflen);
>> xdr_set_scratch_buffer(&stream, page_address(scratch), PAGE_SIZE);
>>
>> @@ -619,27 +615,27 @@ int
>> nfs_readdir_page_filler(nfs_readdir_descriptor_t *desc, struct
>> nfs_entry *en
>> entry->label->len = NFS4_MAXLABELLEN;
>>
>> status = xdr_decode(desc, entry, &stream);
>> - if (status != 0) {
>> - if (status == -EAGAIN)
>> - status = 0;
>> + if (status != 0)
>> break;
>> - }
>> -
>> - count++;
>>
>> if (desc->plus)
>> nfs_prime_dcache(file_dentry(desc->file), entry,
>> desc->dir_verifier);
>>
>> status = nfs_readdir_add_to_array(entry, page);
>> - if (status != 0)
>> - break;
>> - } while (!entry->eof);
>> + } while (!status && !entry->eof);
>>
>> -out_nopages:
>> - if (count == 0 || (status == -EBADCOOKIE && entry->eof != 0)) {
>> - nfs_readdir_page_set_eof(page);
>> + switch (status) {
>> + case -EBADCOOKIE:
>> + if (entry->eof) {
>> + nfs_readdir_page_set_eof(page);
>> + status = 0;
>> + }
>> + break;
>> + case -ENOSPC:
>
> If you return ENOSPC, then you don't need to use
> nfs_readdir_array_is_full(array) below..
>
>> + case -EAGAIN:
>> status = 0;
>> + break;
>> }
>>
>> put_page(scratch);
>> @@ -714,14 +710,15 @@ int
>> nfs_readdir_xdr_to_array(nfs_readdir_descriptor_t *desc, struct page
>> *page,
>>
>> if (status < 0)
>> break;
>> +
>> pglen = status;
>> - status = nfs_readdir_page_filler(desc, &entry, pages, page,
>> pglen);
>> - if (status < 0) {
>> - if (status == -ENOSPC)
>> - status = 0;
>> + if (pglen == 0) {
>> + nfs_readdir_page_set_eof(page);
>> break;
>> }
>> - } while (!nfs_readdir_array_is_full(array));
>> +
>> + status = nfs_readdir_page_filler(desc, &entry, pages, page,
>> pglen);
>> + } while (!status && !nfs_readdir_array_is_full(array));
>
> ^^ here.
>
> I suppose nfs_readdir_array_is_full() is nice and clear.. I wonder if
> the
> compiler would optimize it away.

Ah, I see now -- the check handles the case of eof as well..

I suppose I shouldn't send a stream of consciousness to the list. Sorry
about that.

Ben