2021-02-19 02:03:29

by Trond Myklebust

Subject: [PATCH] nfsd: Don't keep looking up unhashed files in the nfsd file cache

From: Trond Myklebust <[email protected]>

If a file is unhashed, then we're going to reject it anyway and retry,
so make sure we skip it when we're doing the RCU lockless lookup.
This avoids a number of unnecessary nfserr_jukebox returns from
nfsd_file_acquire()

Fixes: 65294c1f2c5e ("nfsd: add a new struct file caching facility to nfsd")
Signed-off-by: Trond Myklebust <[email protected]>
---
fs/nfsd/filecache.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/fs/nfsd/filecache.c b/fs/nfsd/filecache.c
index 53fcbf79bdca..7629248fdd53 100644
--- a/fs/nfsd/filecache.c
+++ b/fs/nfsd/filecache.c
@@ -898,6 +898,8 @@ nfsd_file_find_locked(struct inode *inode, unsigned int may_flags,
continue;
if (!nfsd_match_cred(nf->nf_cred, current_cred()))
continue;
+ if (!test_bit(NFSD_FILE_HASHED, &nf->nf_flags))
+ continue;
if (nfsd_file_get(nf) != NULL)
return nf;
}
--
2.29.2

2021-02-25 03:27:55

by J. Bruce Fields

Subject: Re: [PATCH] nfsd: Don't keep looking up unhashed files in the nfsd file cache

On Thu, Feb 18, 2021 at 09:02:07PM -0500, [email protected] wrote:
> From: Trond Myklebust <[email protected]>
>
> If a file is unhashed, then we're going to reject it anyway and retry,
> so make sure we skip it when we're doing the RCU lockless lookup.
> This avoids a number of unnecessary nfserr_jukebox returns from
> nfsd_file_acquire()

Looks good to me.--b.

>
> Fixes: 65294c1f2c5e ("nfsd: add a new struct file caching facility to nfsd")
> Signed-off-by: Trond Myklebust <[email protected]>
> ---
> fs/nfsd/filecache.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/fs/nfsd/filecache.c b/fs/nfsd/filecache.c
> index 53fcbf79bdca..7629248fdd53 100644
> --- a/fs/nfsd/filecache.c
> +++ b/fs/nfsd/filecache.c
> @@ -898,6 +898,8 @@ nfsd_file_find_locked(struct inode *inode, unsigned int may_flags,
> continue;
> if (!nfsd_match_cred(nf->nf_cred, current_cred()))
> continue;
> + if (!test_bit(NFSD_FILE_HASHED, &nf->nf_flags))
> + continue;
> if (nfsd_file_get(nf) != NULL)
> return nf;
> }
> --
> 2.29.2

2021-02-25 03:28:07

by Chuck Lever

Subject: Re: [PATCH] nfsd: Don't keep looking up unhashed files in the nfsd file cache

> On Feb 24, 2021, at 3:59 PM, J. Bruce Fields <[email protected]> wrote:
>
> On Thu, Feb 18, 2021 at 09:02:07PM -0500, [email protected] wrote:
>> From: Trond Myklebust <[email protected]>
>>
>> If a file is unhashed, then we're going to reject it anyway and retry,
>> so make sure we skip it when we're doing the RCU lockless lookup.
>> This avoids a number of unnecessary nfserr_jukebox returns from
>> nfsd_file_acquire()
>
> Looks good to me.--b.

Thanks for the review. This is now included in the for-rc topic branch at:

git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux.git


>> Fixes: 65294c1f2c5e ("nfsd: add a new struct file caching facility to nfsd")
>> Signed-off-by: Trond Myklebust <[email protected]>
>> ---
>> fs/nfsd/filecache.c | 2 ++
>> 1 file changed, 2 insertions(+)
>>
>> diff --git a/fs/nfsd/filecache.c b/fs/nfsd/filecache.c
>> index 53fcbf79bdca..7629248fdd53 100644
>> --- a/fs/nfsd/filecache.c
>> +++ b/fs/nfsd/filecache.c
>> @@ -898,6 +898,8 @@ nfsd_file_find_locked(struct inode *inode, unsigned int may_flags,
>> continue;
>> if (!nfsd_match_cred(nf->nf_cred, current_cred()))
>> continue;
>> + if (!test_bit(NFSD_FILE_HASHED, &nf->nf_flags))
>> + continue;
>> if (nfsd_file_get(nf) != NULL)
>> return nf;
>> }
>> --
>> 2.29.2

--
Chuck Lever