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Groups > linux.kernel > #1412789
| From | Al Viro <viro@ZenIV.linux.org.uk> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: NFS/d_splice_alias breakage |
| Date | 2016-06-03 06:50 +0200 |
| Message-ID | <rFPdv-73m-7@gated-at.bofh.it> (permalink) |
| References | <rFJUt-3Rl-1@gated-at.bofh.it> <rFO7L-6nc-11@gated-at.bofh.it> <rFOhr-6qj-9@gated-at.bofh.it> <rFOU9-6WX-3@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Fri, Jun 03, 2016 at 05:26:48AM +0100, Al Viro wrote:
> Looks like the right thing to do would be to do d_drop() at no_open:,
> just before we call nfs_lookup(). If not earlier, actually... How
> about the following?
A bit of rationale: dentry in question is negative and attempt to open
it has just failed; in case it's really negative we did that d_drop()
anyway (and then unconditionally rehashed it). In case when we proceed to
nfs_lookup() and it does not fail, we'll have it rehashed there (with the
right inode). What do we lose from doing d_drop() on *any* error here?
It's negative, with dubious validity. In the worst case, we had open
and lookup fail, but it's just us - the sucker really is negative and
somebody else would be able to revalidate it. If we drop it here (and
not rehash later), that somebody else will have to allocate an in-core
dentry before doing lookup or atomic_open. Which is negligible extra
burden.
> diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
> index aaf7bd0..6e3a6f4 100644
> --- a/fs/nfs/dir.c
> +++ b/fs/nfs/dir.c
> @@ -1536,9 +1536,9 @@ int nfs_atomic_open(struct inode *dir, struct dentry *dentry,
> err = PTR_ERR(inode);
> trace_nfs_atomic_open_exit(dir, ctx, open_flags, err);
> put_nfs_open_context(ctx);
> + d_drop(dentry);
> switch (err) {
> case -ENOENT:
> - d_drop(dentry);
> d_add(dentry, NULL);
> nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
> break;
Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread
NFS/d_splice_alias breakage Oleg Drokin <green@linuxhacker.ru> - 2016-06-03 01:10 +0200
[PATCH] Allow d_splice_alias to accept hashed dentries green@linuxhacker.ru - 2016-06-03 02:10 +0200
Re: [PATCH] Allow d_splice_alias to accept hashed dentries Oleg Drokin <green@linuxhacker.ru> - 2016-06-03 02:30 +0200
Re: NFS/d_splice_alias breakage Trond Myklebust <trondmy@primarydata.com> - 2016-06-03 02:50 +0200
Re: NFS/d_splice_alias breakage Oleg Drokin <green@linuxhacker.ru> - 2016-06-03 03:00 +0200
Re: NFS/d_splice_alias breakage Al Viro <viro@ZenIV.linux.org.uk> - 2016-06-03 05:30 +0200
Re: NFS/d_splice_alias breakage Al Viro <viro@ZenIV.linux.org.uk> - 2016-06-03 05:40 +0200
Re: NFS/d_splice_alias breakage Al Viro <viro@ZenIV.linux.org.uk> - 2016-06-03 05:30 +0200
Re: NFS/d_splice_alias breakage Al Viro <viro@ZenIV.linux.org.uk> - 2016-06-03 05:40 +0200
Re: NFS/d_splice_alias breakage Oleg Drokin <green@linuxhacker.ru> - 2016-06-03 05:50 +0200
Re: NFS/d_splice_alias breakage Al Viro <viro@ZenIV.linux.org.uk> - 2016-06-03 06:30 +0200
Re: NFS/d_splice_alias breakage Al Viro <viro@ZenIV.linux.org.uk> - 2016-06-03 06:50 +0200
Re: NFS/d_splice_alias breakage Al Viro <viro@ZenIV.linux.org.uk> - 2016-06-03 07:00 +0200
Re: NFS/d_splice_alias breakage Oleg Drokin <green@linuxhacker.ru> - 2016-06-03 07:00 +0200
Re: NFS/d_splice_alias breakage Al Viro <viro@ZenIV.linux.org.uk> - 2016-06-03 08:00 +0200
Re: NFS/d_splice_alias breakage Oleg Drokin <green@linuxhacker.ru> - 2016-06-07 01:40 +0200
Re: NFS/d_splice_alias breakage Oleg Drokin <green@linuxhacker.ru> - 2016-06-10 03:40 +0200
Re: NFS/d_splice_alias breakage Oleg Drokin <green@linuxhacker.ru> - 2016-06-10 18:50 +0200
Dcache oops Oleg Drokin <green@linuxhacker.ru> - 2016-06-03 18:40 +0200
Re: Dcache oops Al Viro <viro@ZenIV.linux.org.uk> - 2016-06-03 20:30 +0200
Re: Dcache oops Oleg Drokin <green@linuxhacker.ru> - 2016-06-03 20:40 +0200
Re: Dcache oops Al Viro <viro@ZenIV.linux.org.uk> - 2016-06-03 22:10 +0200
Re: Dcache oops Linus Torvalds <torvalds@linux-foundation.org> - 2016-06-03 23:20 +0200
Re: Dcache oops Al Viro <viro@ZenIV.linux.org.uk> - 2016-06-03 23:30 +0200
Re: Dcache oops Linus Torvalds <torvalds@linux-foundation.org> - 2016-06-04 00:10 +0200
Re: Dcache oops Al Viro <viro@ZenIV.linux.org.uk> - 2016-06-04 00:30 +0200
Re: Dcache oops Al Viro <viro@ZenIV.linux.org.uk> - 2016-06-04 00:30 +0200
Re: Dcache oops Al Viro <viro@ZenIV.linux.org.uk> - 2016-06-04 00:40 +0200
Re: Dcache oops Oleg Drokin <green@linuxhacker.ru> - 2016-06-04 00:50 +0200
Re: Dcache oops Oleg Drokin <green@linuxhacker.ru> - 2016-06-04 02:00 +0200
Re: Dcache oops Al Viro <viro@ZenIV.linux.org.uk> - 2016-06-04 03:00 +0200
Re: Dcache oops Jeff Layton <jlayton@poochiereds.net> - 2016-06-04 14:30 +0200
Re: Dcache oops Oleg Drokin <green@linuxhacker.ru> - 2016-06-04 18:20 +0200
[PATCH] nfs4: Fix potential use after free of state in nfs4_do_reclaim. green@linuxhacker.ru - 2016-06-04 18:30 +0200
Re: [PATCH] nfs4: Fix potential use after free of state in nfs4_do_reclaim. Jeff Layton <jlayton@poochiereds.net> - 2016-06-04 22:00 +0200
Re: Dcache oops Linus Torvalds <torvalds@linux-foundation.org> - 2016-06-04 00:40 +0200
Re: Dcache oops Oleg Drokin <green@linuxhacker.ru> - 2016-06-04 00:50 +0200
Re: Dcache oops Al Viro <viro@ZenIV.linux.org.uk> - 2016-06-04 00:50 +0200
Re: Dcache oops Oleg Drokin <green@linuxhacker.ru> - 2016-06-03 23:20 +0200
Re: Dcache oops Al Viro <viro@ZenIV.linux.org.uk> - 2016-06-03 23:50 +0200
Re: Dcache oops Al Viro <viro@ZenIV.linux.org.uk> - 2016-06-04 00:20 +0200
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