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NFS: nfs4_lookup_revalidate: only evaluate parent if it will be used.

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nfs4_lookup_revalidate only uses 'parent' to get 'dir', and only
uses 'dir' if 'inode == NULL'.

So we don't need to find out what 'parent' or 'dir' is until we
know that 'inode' is NULL.

By moving 'dget_parent' inside the 'if', we can reduce the number of
call sites for 'dput(parent)'.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
This commit is contained in:
NeilBrown 2014-07-14 11:28:20 +10:00 committed by Trond Myklebust
parent 1f70ef96b1
commit 49317a7fda
1 changed files with 8 additions and 9 deletions
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17
fs/nfs/dir.c
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@ -1529,9 +1529,7 @@ EXPORT_SYMBOL_GPL(nfs_atomic_open);
static int nfs4_lookup_revalidate(struct dentry *dentry, unsigned int flags)
{
struct dentry *parent = NULL;
struct inode *inode;
struct inode *dir;
int ret = 0;
if (flags & LOOKUP_RCU)
@ -1545,34 +1543,35 @@ static int nfs4_lookup_revalidate(struct dentry *dentry, unsigned int flags)
goto no_open;
inode = dentry->d_inode;
parent = dget_parent(dentry);
dir = parent->d_inode;
/* We can't create new files in nfs_open_revalidate(), so we
* optimize away revalidation of negative dentries.
*/
if (inode == NULL) {
struct dentry *parent;
struct inode *dir;
parent = dget_parent(dentry);
dir = parent->d_inode;
if (!nfs_neg_need_reval(dir, dentry, flags))
ret = 1;
dput(parent);
goto out;
}
/* NFS only supports OPEN on regular files */
if (!S_ISREG(inode->i_mode))
goto no_open_dput;
goto no_open;
/* We cannot do exclusive creation on a positive dentry */
if (flags & LOOKUP_EXCL)
goto no_open_dput;
goto no_open;
/* Let f_op->open() actually open (and revalidate) the file */
ret = 1;
out:
dput(parent);
return ret;
no_open_dput:
dput(parent);
no_open:
return nfs_lookup_revalidate(dentry, flags);
}