NFS: Refactor nfs_lookup_revalidate()
Refactor the code in nfs_lookup_revalidate() as a stepping stone towards optimising and fixing nfs4_lookup_revalidate(). Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
This commit is contained in:
Trond Myklebust
parent
be189f7e7f
commit
5ceb9d7fda
284
fs/nfs/dir.c
284
fs/nfs/dir.c
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@ -1072,129 +1072,16 @@ int nfs_neg_need_reval(struct inode *dir, struct dentry *dentry,
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return !nfs_check_verifier(dir, dentry, flags & LOOKUP_RCU);
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}
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/*
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* This is called every time the dcache has a lookup hit,
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* and we should check whether we can really trust that
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* lookup.
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*
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* NOTE! The hit can be a negative hit too, don't assume
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* we have an inode!
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*
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* If the parent directory is seen to have changed, we throw out the
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* cached dentry and do a new lookup.
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*/
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static int nfs_lookup_revalidate(struct dentry *dentry, unsigned int flags)
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static int
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nfs_lookup_revalidate_done(struct inode *dir, struct dentry *dentry,
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struct inode *inode, int error)
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{
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struct inode *dir;
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struct inode *inode;
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struct dentry *parent;
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struct nfs_fh *fhandle = NULL;
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struct nfs_fattr *fattr = NULL;
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struct nfs4_label *label = NULL;
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int error;
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if (flags & LOOKUP_RCU) {
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parent = READ_ONCE(dentry->d_parent);
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dir = d_inode_rcu(parent);
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if (!dir)
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return -ECHILD;
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} else {
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parent = dget_parent(dentry);
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dir = d_inode(parent);
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}
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nfs_inc_stats(dir, NFSIOS_DENTRYREVALIDATE);
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inode = d_inode(dentry);
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if (!inode) {
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if (nfs_neg_need_reval(dir, dentry, flags)) {
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if (flags & LOOKUP_RCU)
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return -ECHILD;
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goto out_bad;
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}
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goto out_valid;
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}
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if (is_bad_inode(inode)) {
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if (flags & LOOKUP_RCU)
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return -ECHILD;
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dfprintk(LOOKUPCACHE, "%s: %pd2 has dud inode\n",
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__func__, dentry);
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goto out_bad;
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}
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if (NFS_PROTO(dir)->have_delegation(inode, FMODE_READ))
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goto out_set_verifier;
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/* Force a full look up iff the parent directory has changed */
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if (!(flags & (LOOKUP_EXCL | LOOKUP_REVAL)) &&
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nfs_check_verifier(dir, dentry, flags & LOOKUP_RCU)) {
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error = nfs_lookup_verify_inode(inode, flags);
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if (error) {
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if (flags & LOOKUP_RCU)
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return -ECHILD;
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if (error == -ESTALE)
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goto out_zap_parent;
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goto out_error;
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}
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nfs_advise_use_readdirplus(dir);
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goto out_valid;
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}
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if (flags & LOOKUP_RCU)
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return -ECHILD;
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if (NFS_STALE(inode))
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goto out_bad;
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error = -ENOMEM;
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fhandle = nfs_alloc_fhandle();
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fattr = nfs_alloc_fattr();
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if (fhandle == NULL || fattr == NULL)
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goto out_error;
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label = nfs4_label_alloc(NFS_SERVER(inode), GFP_NOWAIT);
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if (IS_ERR(label))
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goto out_error;
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trace_nfs_lookup_revalidate_enter(dir, dentry, flags);
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error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, fhandle, fattr, label);
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trace_nfs_lookup_revalidate_exit(dir, dentry, flags, error);
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if (error == -ESTALE || error == -ENOENT)
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goto out_bad;
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if (error)
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goto out_error;
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if (nfs_compare_fh(NFS_FH(inode), fhandle))
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goto out_bad;
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if ((error = nfs_refresh_inode(inode, fattr)) != 0)
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goto out_bad;
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nfs_setsecurity(inode, fattr, label);
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nfs_free_fattr(fattr);
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nfs_free_fhandle(fhandle);
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nfs4_label_free(label);
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/* set a readdirplus hint that we had a cache miss */
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nfs_force_use_readdirplus(dir);
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out_set_verifier:
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nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
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out_valid:
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if (flags & LOOKUP_RCU) {
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if (parent != READ_ONCE(dentry->d_parent))
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return -ECHILD;
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} else
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dput(parent);
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switch (error) {
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case 1:
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dfprintk(LOOKUPCACHE, "NFS: %s(%pd2) is valid\n",
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__func__, dentry);
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return 1;
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out_zap_parent:
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nfs_zap_caches(dir);
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out_bad:
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WARN_ON(flags & LOOKUP_RCU);
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nfs_free_fattr(fattr);
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nfs_free_fhandle(fhandle);
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nfs4_label_free(label);
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case 0:
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nfs_mark_for_revalidate(dir);
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if (inode && S_ISDIR(inode->i_mode)) {
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/* Purge readdir caches. */
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@ -1206,23 +1093,166 @@ out_zap_parent:
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* inodes on unmount and further oopses.
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*/
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if (IS_ROOT(dentry))
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goto out_valid;
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return 1;
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}
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dput(parent);
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dfprintk(LOOKUPCACHE, "NFS: %s(%pd2) is invalid\n",
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__func__, dentry);
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return 0;
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out_error:
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WARN_ON(flags & LOOKUP_RCU);
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nfs_free_fattr(fattr);
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nfs_free_fhandle(fhandle);
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nfs4_label_free(label);
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dput(parent);
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}
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dfprintk(LOOKUPCACHE, "NFS: %s(%pd2) lookup returned error %d\n",
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__func__, dentry, error);
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return error;
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}
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static int
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nfs_lookup_revalidate_negative(struct inode *dir, struct dentry *dentry,
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unsigned int flags)
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{
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int ret = 1;
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if (nfs_neg_need_reval(dir, dentry, flags)) {
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if (flags & LOOKUP_RCU)
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return -ECHILD;
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ret = 0;
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}
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return nfs_lookup_revalidate_done(dir, dentry, NULL, ret);
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}
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static int
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nfs_lookup_revalidate_delegated(struct inode *dir, struct dentry *dentry,
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struct inode *inode)
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{
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nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
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return nfs_lookup_revalidate_done(dir, dentry, inode, 1);
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}
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static int
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nfs_lookup_revalidate_dentry(struct inode *dir, struct dentry *dentry,
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struct inode *inode)
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{
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struct nfs_fh *fhandle;
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struct nfs_fattr *fattr;
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struct nfs4_label *label;
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int ret;
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ret = -ENOMEM;
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fhandle = nfs_alloc_fhandle();
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fattr = nfs_alloc_fattr();
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label = nfs4_label_alloc(NFS_SERVER(inode), GFP_KERNEL);
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if (fhandle == NULL || fattr == NULL || IS_ERR(label))
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goto out;
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ret = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, fhandle, fattr, label);
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if (ret < 0) {
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if (ret == -ESTALE || ret == -ENOENT)
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ret = 0;
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goto out;
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}
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ret = 0;
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if (nfs_compare_fh(NFS_FH(inode), fhandle))
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goto out;
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if (nfs_refresh_inode(inode, fattr) < 0)
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goto out;
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nfs_setsecurity(inode, fattr, label);
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nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
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/* set a readdirplus hint that we had a cache miss */
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nfs_force_use_readdirplus(dir);
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ret = 1;
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out:
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nfs_free_fattr(fattr);
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nfs_free_fhandle(fhandle);
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nfs4_label_free(label);
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return nfs_lookup_revalidate_done(dir, dentry, inode, ret);
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}
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/*
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* This is called every time the dcache has a lookup hit,
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* and we should check whether we can really trust that
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* lookup.
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*
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* NOTE! The hit can be a negative hit too, don't assume
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* we have an inode!
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*
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* If the parent directory is seen to have changed, we throw out the
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* cached dentry and do a new lookup.
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*/
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static int
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nfs_do_lookup_revalidate(struct inode *dir, struct dentry *dentry,
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unsigned int flags)
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{
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struct inode *inode;
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int error;
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nfs_inc_stats(dir, NFSIOS_DENTRYREVALIDATE);
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inode = d_inode(dentry);
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if (!inode)
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return nfs_lookup_revalidate_negative(dir, dentry, flags);
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if (is_bad_inode(inode)) {
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dfprintk(LOOKUPCACHE, "%s: %pd2 has dud inode\n",
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__func__, dentry);
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goto out_bad;
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}
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if (NFS_PROTO(dir)->have_delegation(inode, FMODE_READ))
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return nfs_lookup_revalidate_delegated(dir, dentry, inode);
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/* Force a full look up iff the parent directory has changed */
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if (!(flags & (LOOKUP_EXCL | LOOKUP_REVAL)) &&
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nfs_check_verifier(dir, dentry, flags & LOOKUP_RCU)) {
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error = nfs_lookup_verify_inode(inode, flags);
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if (error) {
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if (error == -ESTALE)
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nfs_zap_caches(dir);
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goto out_bad;
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}
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nfs_advise_use_readdirplus(dir);
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goto out_valid;
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}
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if (flags & LOOKUP_RCU)
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return -ECHILD;
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if (NFS_STALE(inode))
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goto out_bad;
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trace_nfs_lookup_revalidate_enter(dir, dentry, flags);
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error = nfs_lookup_revalidate_dentry(dir, dentry, inode);
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trace_nfs_lookup_revalidate_exit(dir, dentry, flags, error);
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return error;
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out_valid:
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return nfs_lookup_revalidate_done(dir, dentry, inode, 1);
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out_bad:
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if (flags & LOOKUP_RCU)
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return -ECHILD;
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return nfs_lookup_revalidate_done(dir, dentry, inode, 0);
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}
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static int
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nfs_lookup_revalidate(struct dentry *dentry, unsigned int flags)
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{
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struct dentry *parent;
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struct inode *dir;
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int ret;
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if (flags & LOOKUP_RCU) {
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parent = READ_ONCE(dentry->d_parent);
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dir = d_inode_rcu(parent);
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if (!dir)
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return -ECHILD;
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ret = nfs_do_lookup_revalidate(dir, dentry, flags);
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if (parent != READ_ONCE(dentry->d_parent))
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return -ECHILD;
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} else {
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parent = dget_parent(dentry);
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ret = nfs_do_lookup_revalidate(d_inode(parent), dentry, flags);
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dput(parent);
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}
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return ret;
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}
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/*
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* A weaker form of d_revalidate for revalidating just the d_inode(dentry)
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* when we don't really care about the dentry name. This is called when a
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