* [PATCH] NFSD, VFS: Remove dead code in nfsd_rename()
@ 2011-03-05 23:30 Jesper Juhl
2011-03-06 5:52 ` NeilBrown
0 siblings, 1 reply; 3+ messages in thread
From: Jesper Juhl @ 2011-03-05 23:30 UTC (permalink / raw)
To: linux-nfs; +Cc: linux-kernel, Neil Brown, J. Bruce Fields, Trond Myklebust
Currently we have the following code in fs/nfsd/vfs.c::nfsd_rename() :
...
host_err = nfsd_break_lease(odentry->d_inode);
if (host_err)
goto out_drop_write;
if (ndentry->d_inode) {
host_err = nfsd_break_lease(ndentry->d_inode);
if (host_err)
goto out_drop_write;
}
if (host_err)
goto out_drop_write;
...
'host_err' is guaranteed to be 0 by the time we test 'ndentry->d_inode'.
If 'host_err' becomes != 0 inside the 'if' statement, then we goto
'out_drop_write'. So, after the 'if' statement there is no way that
'host_err' can be anything but 0, so the test afterwards is just dead
code.
This patch removes the dead code.
Signed-off-by: Jesper Juhl <jj@chaosbits.net>
---
vfs.c | 2 --
1 file changed, 2 deletions(-)
diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index da1d970..9cc626b 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -1749,8 +1749,6 @@ nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen,
if (host_err)
goto out_drop_write;
}
- if (host_err)
- goto out_drop_write;
host_err = vfs_rename(fdir, odentry, tdir, ndentry);
if (!host_err) {
host_err = commit_metadata(tfhp);
--
Jesper Juhl <jj@chaosbits.net> http://www.chaosbits.net/
Plain text mails only, please.
Don't top-post http://www.catb.org/~esr/jargon/html/T/top-post.html
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH] NFSD, VFS: Remove dead code in nfsd_rename()
2011-03-05 23:30 [PATCH] NFSD, VFS: Remove dead code in nfsd_rename() Jesper Juhl
@ 2011-03-06 5:52 ` NeilBrown
2011-03-07 16:58 ` J. Bruce Fields
0 siblings, 1 reply; 3+ messages in thread
From: NeilBrown @ 2011-03-06 5:52 UTC (permalink / raw)
To: Jesper Juhl; +Cc: linux-nfs, linux-kernel, J. Bruce Fields, Trond Myklebust
On Sun, 6 Mar 2011 00:30:35 +0100 (CET) Jesper Juhl <jj@chaosbits.net> wrote:
> Currently we have the following code in fs/nfsd/vfs.c::nfsd_rename() :
>
> ...
> host_err = nfsd_break_lease(odentry->d_inode);
> if (host_err)
> goto out_drop_write;
> if (ndentry->d_inode) {
> host_err = nfsd_break_lease(ndentry->d_inode);
> if (host_err)
> goto out_drop_write;
> }
> if (host_err)
> goto out_drop_write;
> ...
>
> 'host_err' is guaranteed to be 0 by the time we test 'ndentry->d_inode'.
> If 'host_err' becomes != 0 inside the 'if' statement, then we goto
> 'out_drop_write'. So, after the 'if' statement there is no way that
> 'host_err' can be anything but 0, so the test afterwards is just dead
> code.
> This patch removes the dead code.
I would probably have gone for:
host_err = nfsd_break_lease(odentry->d_inode);
if (!host_err && ndentry->d_inode)
host_err = nfsd_break_lease(ndentry->d_inode);
if (host_err)
goto out_drop_write;
or even
host_err = nfsd_break_lease(odentry->d_inode);
if (ndentry->d_inode)
host_err = hosterr ?: nfsd_break_lease(ndentry->d_inode);
if (host_err)
goto out_drop_write;
but it is largely a matter of taste. I agree there is redundant code there
and your's is a suitable fix.
NeilBrown
>
> Signed-off-by: Jesper Juhl <jj@chaosbits.net>
> ---
> vfs.c | 2 --
> 1 file changed, 2 deletions(-)
>
> diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
> index da1d970..9cc626b 100644
> --- a/fs/nfsd/vfs.c
> +++ b/fs/nfsd/vfs.c
> @@ -1749,8 +1749,6 @@ nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen,
> if (host_err)
> goto out_drop_write;
> }
> - if (host_err)
> - goto out_drop_write;
> host_err = vfs_rename(fdir, odentry, tdir, ndentry);
> if (!host_err) {
> host_err = commit_metadata(tfhp);
>
>
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] NFSD, VFS: Remove dead code in nfsd_rename()
2011-03-06 5:52 ` NeilBrown
@ 2011-03-07 16:58 ` J. Bruce Fields
0 siblings, 0 replies; 3+ messages in thread
From: J. Bruce Fields @ 2011-03-07 16:58 UTC (permalink / raw)
To: NeilBrown; +Cc: Jesper Juhl, linux-nfs, linux-kernel, Trond Myklebust
On Sun, Mar 06, 2011 at 04:52:42PM +1100, NeilBrown wrote:
> On Sun, 6 Mar 2011 00:30:35 +0100 (CET) Jesper Juhl <jj@chaosbits.net> wrote:
>
> > Currently we have the following code in fs/nfsd/vfs.c::nfsd_rename() :
> >
> > ...
> > host_err = nfsd_break_lease(odentry->d_inode);
> > if (host_err)
> > goto out_drop_write;
> > if (ndentry->d_inode) {
> > host_err = nfsd_break_lease(ndentry->d_inode);
> > if (host_err)
> > goto out_drop_write;
> > }
> > if (host_err)
> > goto out_drop_write;
> > ...
> >
> > 'host_err' is guaranteed to be 0 by the time we test 'ndentry->d_inode'.
> > If 'host_err' becomes != 0 inside the 'if' statement, then we goto
> > 'out_drop_write'. So, after the 'if' statement there is no way that
> > 'host_err' can be anything but 0, so the test afterwards is just dead
> > code.
> > This patch removes the dead code.
>
> I would probably have gone for:
>
> host_err = nfsd_break_lease(odentry->d_inode);
> if (!host_err && ndentry->d_inode)
> host_err = nfsd_break_lease(ndentry->d_inode);
> if (host_err)
> goto out_drop_write;
>
> or even
> host_err = nfsd_break_lease(odentry->d_inode);
> if (ndentry->d_inode)
> host_err = hosterr ?: nfsd_break_lease(ndentry->d_inode);
> if (host_err)
> goto out_drop_write;
>
>
> but it is largely a matter of taste. I agree there is redundant code there
> and your's is a suitable fix.
Yeah, works for me. Thanks for catching that; queueing up for 2.6.39.
--b.
>
> NeilBrown
>
> >
> > Signed-off-by: Jesper Juhl <jj@chaosbits.net>
> > ---
> > vfs.c | 2 --
> > 1 file changed, 2 deletions(-)
> >
> > diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
> > index da1d970..9cc626b 100644
> > --- a/fs/nfsd/vfs.c
> > +++ b/fs/nfsd/vfs.c
> > @@ -1749,8 +1749,6 @@ nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen,
> > if (host_err)
> > goto out_drop_write;
> > }
> > - if (host_err)
> > - goto out_drop_write;
> > host_err = vfs_rename(fdir, odentry, tdir, ndentry);
> > if (!host_err) {
> > host_err = commit_metadata(tfhp);
> >
> >
>
^ permalink raw reply [flat|nested] 3+ messages in thread
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2011-03-05 23:30 [PATCH] NFSD, VFS: Remove dead code in nfsd_rename() Jesper Juhl
2011-03-06 5:52 ` NeilBrown
2011-03-07 16:58 ` J. Bruce Fields
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