All of lore.kernel.org
 help / color / mirror / Atom feed
From: Trond Myklebust <trondmy@hammerspace.com>
To: "schumakeranna@gmail.com" <schumakeranna@gmail.com>,
	"bfields@redhat.com" <bfields@redhat.com>
Cc: "linux-nfs@vger.kernel.org" <linux-nfs@vger.kernel.org>,
	"daire@dneg.com" <daire@dneg.com>
Subject: Re: [PATCH 3/3] nfs: don't allow reexport reclaims
Date: Mon, 14 Jun 2021 14:56:55 +0000	[thread overview]
Message-ID: <3189d061c1e862fe305e501226fcc9ebc1fe544d.camel@hammerspace.com> (raw)
In-Reply-To: <1623682098-13236-4-git-send-email-bfields@redhat.com>

On Mon, 2021-06-14 at 10:48 -0400, J. Bruce Fields wrote:
> From: "J. Bruce Fields" <bfields@redhat.com>
> 
> In the reexport case, nfsd is currently passing along locks with the
> reclaim bit set.  The client sends a new lock request, which is
> granted
> if there's currently no conflict--even if it's possible a conflicting
> lock could have been briefly held in the interim.
> 
> We don't currently have any way to safely grant reclaim, so for now
> let's just deny them all.
> 
> I'm doing this by passing the reclaim bit to nfs and letting it fail
> the
> call, with the idea that eventually the client might be able to do
> something more forgiving here.
> 
> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
> ---
>  fs/nfs/file.c       | 3 +++
>  fs/nfsd/nfs4state.c | 3 +++
>  fs/nfsd/nfsproc.c   | 1 +
>  include/linux/fs.h  | 1 +
>  4 files changed, 8 insertions(+)
> 
> diff --git a/fs/nfs/file.c b/fs/nfs/file.c
> index 1fef107961bc..35a29b440e3e 100644
> --- a/fs/nfs/file.c
> +++ b/fs/nfs/file.c
> @@ -806,6 +806,9 @@ int nfs_lock(struct file *filp, int cmd, struct
> file_lock *fl)
>  
>         nfs_inc_stats(inode, NFSIOS_VFSLOCK);
>  
> +       if (fl->fl_flags & FL_RECLAIM)
> +               return -NFSERR_NO_GRACE;

NACK. nfs_lock() is required to return a POSIX error. I know that right
now, nfsd is the only thing setting FL_RECLAIM, but we can't guarantee
that will always be the case.

> +
>         /* No mandatory locks over NFS */
>         if (__mandatory_lock(inode) && fl->fl_type != F_UNLCK)
>                 goto out_err;
> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> index 00d98bbab2a6..3ef42c0d5d38 100644
> --- a/fs/nfsd/nfs4state.c
> +++ b/fs/nfsd/nfs4state.c
> @@ -6903,6 +6903,9 @@ nfsd4_lock(struct svc_rqst *rqstp, struct
> nfsd4_compound_state *cstate,
>         if (!locks_in_grace(net) && lock->lk_reclaim)
>                 goto out;
>  
> +       if (lock->lk_reclaim)
> +               fl_flags |= FL_RECLAIM;
> +
>         fp = lock_stp->st_stid.sc_file;
>         switch (lock->lk_type) {
>                 case NFS4_READW_LT:
> diff --git a/fs/nfsd/nfsproc.c b/fs/nfsd/nfsproc.c
> index 60d7c59e7935..80c430c37ab7 100644
> --- a/fs/nfsd/nfsproc.c
> +++ b/fs/nfsd/nfsproc.c
> @@ -881,6 +881,7 @@ nfserrno (int errno)
>                 { nfserr_serverfault, -ENFILE },
>                 { nfserr_io, -EUCLEAN },
>                 { nfserr_perm, -ENOKEY },
> +               { nfserr_no_grace, -NFSERR_NO_GRACE},
>         };
>         int     i;
>  
> diff --git a/include/linux/fs.h b/include/linux/fs.h
> index c3c88fdb9b2a..9be479999109 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -997,6 +997,7 @@ static inline struct file *get_file(struct file
> *f)
>  #define FL_UNLOCK_PENDING      512 /* Lease is being broken */
>  #define FL_OFDLCK      1024    /* lock is "owned" by struct file */
>  #define FL_LAYOUT      2048    /* outstanding pNFS layout */
> +#define FL_RECLAIM     4096    /* reclaiming from a reboot server */
>  
>  #define FL_CLOSE_POSIX (FL_POSIX | FL_CLOSE)
>  

-- 
Trond Myklebust
Linux NFS client maintainer, Hammerspace
trond.myklebust@hammerspace.com



  reply	other threads:[~2021-06-14 14:57 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-14 14:48 [PATCH 0/3] reexport lock fixes J. Bruce Fields
2021-06-14 14:48 ` [PATCH 1/3] nfs: don't atempt blocking locks on nfs reexports J. Bruce Fields
2021-06-14 14:48 ` [PATCH 2/3] lockd: lockd server-side shouldn't set fl_ops J. Bruce Fields
2021-06-14 14:48 ` [PATCH 3/3] nfs: don't allow reexport reclaims J. Bruce Fields
2021-06-14 14:56   ` Trond Myklebust [this message]
2021-06-14 19:34     ` J. Bruce Fields
2021-06-14 19:53       ` Trond Myklebust
2021-06-14 20:03         ` bfields
2021-06-14 21:03           ` Trond Myklebust
2021-07-22 14:34             ` bfields

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=3189d061c1e862fe305e501226fcc9ebc1fe544d.camel@hammerspace.com \
    --to=trondmy@hammerspace.com \
    --cc=bfields@redhat.com \
    --cc=daire@dneg.com \
    --cc=linux-nfs@vger.kernel.org \
    --cc=schumakeranna@gmail.com \
    --subject='Re: [PATCH 3/3] nfs: don'\''t allow reexport reclaims' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.