1// SPDX-License-Identifier: GPL-2.0
2/*
3 * (C) 2001 Clemson University and The University of Chicago
4 *
5 * See COPYING in top-level directory.
6 */
7
8/*
9 *  Implementation of dentry (directory cache) functions.
10 */
11
12#include "protocol.h"
13#include "orangefs-kernel.h"
14
15/* Returns 1 if dentry can still be trusted, else 0. */
16static int orangefs_revalidate_lookup(struct dentry *dentry)
17{
18	struct dentry *parent_dentry = dget_parent(dentry);
19	struct inode *parent_inode = parent_dentry->d_inode;
20	struct orangefs_inode_s *parent = ORANGEFS_I(parent_inode);
21	struct inode *inode = dentry->d_inode;
22	struct orangefs_kernel_op_s *new_op;
23	int ret = 0;
24	int err = 0;
25
26	gossip_debug(GOSSIP_DCACHE_DEBUG, "%s: attempting lookup.\n", __func__);
27
28	new_op = op_alloc(ORANGEFS_VFS_OP_LOOKUP);
29	if (!new_op) {
30		ret = -ENOMEM;
31		goto out_put_parent;
32	}
33
34	new_op->upcall.req.lookup.sym_follow = ORANGEFS_LOOKUP_LINK_NO_FOLLOW;
35	new_op->upcall.req.lookup.parent_refn = parent->refn;
36	strncpy(new_op->upcall.req.lookup.d_name,
37		dentry->d_name.name,
38		ORANGEFS_NAME_MAX - 1);
39
40	gossip_debug(GOSSIP_DCACHE_DEBUG,
41		     "%s:%s:%d interrupt flag [%d]\n",
42		     __FILE__,
43		     __func__,
44		     __LINE__,
45		     get_interruptible_flag(parent_inode));
46
47	err = service_operation(new_op, "orangefs_lookup",
48			get_interruptible_flag(parent_inode));
49
50	/* Positive dentry: reject if error or not the same inode. */
51	if (inode) {
52		if (err) {
53			gossip_debug(GOSSIP_DCACHE_DEBUG,
54			    "%s:%s:%d lookup failure.\n",
55			    __FILE__, __func__, __LINE__);
56			goto out_drop;
57		}
58		if (!match_handle(new_op->downcall.resp.lookup.refn.khandle,
59		    inode)) {
60			gossip_debug(GOSSIP_DCACHE_DEBUG,
61			    "%s:%s:%d no match.\n",
62			    __FILE__, __func__, __LINE__);
63			goto out_drop;
64		}
65
66	/* Negative dentry: reject if success or error other than ENOENT. */
67	} else {
68		gossip_debug(GOSSIP_DCACHE_DEBUG, "%s: negative dentry.\n",
69		    __func__);
70		if (!err || err != -ENOENT) {
71			if (new_op->downcall.status != 0)
72				gossip_debug(GOSSIP_DCACHE_DEBUG,
73				    "%s:%s:%d lookup failure.\n",
74				    __FILE__, __func__, __LINE__);
75			goto out_drop;
76		}
77	}
78
79	orangefs_set_timeout(dentry);
80	ret = 1;
81out_release_op:
82	op_release(new_op);
83out_put_parent:
84	dput(parent_dentry);
85	return ret;
86out_drop:
87	gossip_debug(GOSSIP_DCACHE_DEBUG, "%s:%s:%d revalidate failed\n",
88	    __FILE__, __func__, __LINE__);
89	goto out_release_op;
90}
91
92/*
93 * Verify that dentry is valid.
94 *
95 * Should return 1 if dentry can still be trusted, else 0.
96 */
97static int orangefs_d_revalidate(struct dentry *dentry, unsigned int flags)
98{
99	int ret;
100	unsigned long time = (unsigned long) dentry->d_fsdata;
101
102	if (time_before(jiffies, time))
103		return 1;
104
105	if (flags & LOOKUP_RCU)
106		return -ECHILD;
107
108	gossip_debug(GOSSIP_DCACHE_DEBUG, "%s: called on dentry %p.\n",
109		     __func__, dentry);
110
111	/* skip root handle lookups. */
112	if (dentry->d_inode && is_root_handle(dentry->d_inode))
113		return 1;
114
115	/*
116	 * If this passes, the positive dentry still exists or the negative
117	 * dentry still does not exist.
118	 */
119	if (!orangefs_revalidate_lookup(dentry))
120		return 0;
121
122	/* We do not need to continue with negative dentries. */
123	if (!dentry->d_inode) {
124		gossip_debug(GOSSIP_DCACHE_DEBUG,
125		    "%s: negative dentry or positive dentry and inode valid.\n",
126		    __func__);
127		return 1;
128	}
129
130	/* Now we must perform a getattr to validate the inode contents. */
131
132	ret = orangefs_inode_check_changed(dentry->d_inode);
133	if (ret < 0) {
134		gossip_debug(GOSSIP_DCACHE_DEBUG, "%s:%s:%d getattr failure.\n",
135		    __FILE__, __func__, __LINE__);
136		return 0;
137	}
138	return !ret;
139}
140
141const struct dentry_operations orangefs_dentry_operations = {
142	.d_revalidate = orangefs_d_revalidate,
143};
144