diff mbox series

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

Message ID 20201102180658.6218-4-trondmy@kernel.org (mailing list archive)
State New
Headers show
Series Readdir enhancements | expand

Commit Message

trondmy@kernel.org Nov. 2, 2020, 6:06 p.m. UTC
From: Trond Myklebust <trond.myklebust@hammerspace.com>

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

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
---
 fs/nfs/dir.c | 39 ++++++++++++++++++---------------------
 1 file changed, 18 insertions(+), 21 deletions(-)

Comments

Benjamin Coddington Nov. 3, 2020, 2:18 p.m. UTC | #1
On 2 Nov 2020, at 13:06, trondmy@kernel.org wrote:

> From: Trond Myklebust <trond.myklebust@hammerspace.com>
>
> Clean up handling of the case where there are no entries in the 
> readdir
> reply.
>
> Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
> ---
>  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
Benjamin Coddington Nov. 3, 2020, 2:24 p.m. UTC | #2
On 3 Nov 2020, at 9:18, Benjamin Coddington wrote:

> On 2 Nov 2020, at 13:06, trondmy@kernel.org wrote:
>
>> From: Trond Myklebust <trond.myklebust@hammerspace.com>
>>
>> Clean up handling of the case where there are no entries in the 
>> readdir
>> reply.
>>
>> Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
>> ---
>>  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
diff mbox series

Patch

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: