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