[PATCH] NFS: Don't invalidate directory mapping until attributes expire

[PATCH] NFS: Don't invalidate directory mapping until attributes expire

[Benjamin Coddington]

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@redhat.com>
---
 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

Re: [PATCH] NFS: Don't invalidate directory mapping until attributes expire

[Trond Myklebust]

> On Aug 24, 2016, at 13:27, Benjamin Coddington <bcodding@redhat.com> wrot=
e:
>=20
> 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 mappi=
ng
> on subsequent calls into nfs_readdir().  Add that optimization back here.
>=20
> A directory modified once every second and containing 40k entries takes m=
y
> system around 80 seconds to list.  With this patch, that time is reduced =
to
> 7 seconds.
>=20
> Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
> ---
> fs/nfs/dir.c | 13 +------------
> 1 file changed, 1 insertion(+), 12 deletions(-)
>=20
> 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)
> =09goto out;
> }
>=20
> -static bool nfs_dir_mapping_need_revalidate(struct inode *dir)
> -{
> -=09struct nfs_inode *nfsi =3D NFS_I(dir);
> -
> -=09if (nfs_attribute_cache_expired(dir))
> -=09=09return true;
> -=09if (nfsi->cache_validity & NFS_INO_INVALID_DATA)
> -=09=09return true;
> -=09return 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)
> =09desc->decode =3D NFS_PROTO(inode)->decode_dirent;
> =09desc->plus =3D nfs_use_readdirplus(inode, ctx) ? 1 : 0;
>=20
> -=09if (ctx->pos =3D=3D 0 || nfs_dir_mapping_need_revalidate(inode))
> +=09if (ctx->pos =3D=3D 0 || nfs_attribute_cache_expired(inode))
> =09=09res =3D nfs_revalidate_mapping(inode, file->f_mapping);
> =09if (res < 0)
> =09=09goto out;
> --=20
> 2.5.5
>=20

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().

Re: [PATCH] Don't invalidate directory mapping until attributes expire

[Benjamin Coddington]

>> On Aug 24, 2016, at 13:27, Benjamin Coddington <bcodding@redhat.com> 
>> 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@redhat.com>
>> ---
>> 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().

Hi Trond, I did not correctly understand the case for commit 
311324ad1713,
but re-reading the original posting thread has fixed me up.  I'll send a 
v2
that handles both cases.

Ben

[PATCH v2] NFS: Don't invalidate directory mapping until attributes expire

[Benjamin Coddington]

This approach uses another bit in the inode flags..  if that's too expensive
for this ls -l optimization, I will look for another way.

Change from v1:
	Doesn't completely break the commit 311324ad1713 functionality.

8<-----------------------------------------------------------------------------

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@redhat.com>
---
 fs/nfs/dir.c           | 3 ++-
 include/linux/nfs_fs.h | 1 +
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index 19d93d0cd400..88f5dd561025 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -477,6 +477,7 @@ void nfs_force_use_readdirplus(struct inode *dir)
 {
 	if (!list_empty(&NFS_I(dir)->open_files)) {
 		nfs_advise_use_readdirplus(dir);
+		set_bit(NFS_INO_FORCE_RDPLUS, &NFS_I(dir)->flags);
 		nfs_zap_mapping(dir, dir->i_mapping);
 	}
 }
@@ -878,7 +879,7 @@ static bool nfs_dir_mapping_need_revalidate(struct inode *dir)
 
 	if (nfs_attribute_cache_expired(dir))
 		return true;
-	if (nfsi->cache_validity & NFS_INO_INVALID_DATA)
+	if (test_and_clear_bit(NFS_INO_FORCE_RDPLUS, &nfsi->flags))
 		return true;
 	return false;
 }
diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h
index d71278c3c5bd..729cddb7364f 100644
--- a/include/linux/nfs_fs.h
+++ b/include/linux/nfs_fs.h
@@ -211,6 +211,7 @@ struct nfs_inode {
 #define NFS_INO_LAYOUTCOMMIT	(9)		/* layoutcommit required */
 #define NFS_INO_LAYOUTCOMMITTING (10)		/* layoutcommit inflight */
 #define NFS_INO_LAYOUTSTATS	(11)		/* layoutstats inflight */
+#define NFS_INO_FORCE_RDPLUS	(12)		/* force readdirplus */
 
 static inline struct nfs_inode *NFS_I(const struct inode *inode)
 {
-- 
2.5.5

Re: [PATCH v2] Don't invalidate directory mapping until attributes expire

[Benjamin Coddington]

Any issues with this one?

On 26 Aug 2016, at 11:37, Benjamin Coddington wrote:

> This approach uses another bit in the inode flags..  if that's too 
> expensive
> for this ls -l optimization, I will look for another way.
>
> Change from v1:
> 	Doesn't completely break the commit 311324ad1713 functionality.
>
> 8<-----------------------------------------------------------------------------
>
> 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@redhat.com>
> ---
>  fs/nfs/dir.c           | 3 ++-
>  include/linux/nfs_fs.h | 1 +
>  2 files changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
> index 19d93d0cd400..88f5dd561025 100644
> --- a/fs/nfs/dir.c
> +++ b/fs/nfs/dir.c
> @@ -477,6 +477,7 @@ void nfs_force_use_readdirplus(struct inode *dir)
>  {
>  	if (!list_empty(&NFS_I(dir)->open_files)) {
>  		nfs_advise_use_readdirplus(dir);
> +		set_bit(NFS_INO_FORCE_RDPLUS, &NFS_I(dir)->flags);
>  		nfs_zap_mapping(dir, dir->i_mapping);
>  	}
>  }
> @@ -878,7 +879,7 @@ static bool nfs_dir_mapping_need_revalidate(struct 
> inode *dir)
>
>  	if (nfs_attribute_cache_expired(dir))
>  		return true;
> -	if (nfsi->cache_validity & NFS_INO_INVALID_DATA)
> +	if (test_and_clear_bit(NFS_INO_FORCE_RDPLUS, &nfsi->flags))
>  		return true;
>  	return false;
>  }
> diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h
> index d71278c3c5bd..729cddb7364f 100644
> --- a/include/linux/nfs_fs.h
> +++ b/include/linux/nfs_fs.h
> @@ -211,6 +211,7 @@ struct nfs_inode {
>  #define NFS_INO_LAYOUTCOMMIT	(9)		/* layoutcommit required */
>  #define NFS_INO_LAYOUTCOMMITTING (10)		/* layoutcommit inflight */
>  #define NFS_INO_LAYOUTSTATS	(11)		/* layoutstats inflight */
> +#define NFS_INO_FORCE_RDPLUS	(12)		/* force readdirplus */
>
>  static inline struct nfs_inode *NFS_I(const struct inode *inode)
>  {
> -- 
> 2.5.5
>
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