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. */
orangefs_revalidate_lookup(struct dentry * dentry)16  static 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;
81  out_release_op:
82  	op_release(new_op);
83  out_put_parent:
84  	dput(parent_dentry);
85  	return ret;
86  out_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   */
orangefs_d_revalidate(struct dentry * dentry,unsigned int flags)97  static 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  
141  const struct dentry_operations orangefs_dentry_operations = {
142  	.d_revalidate = orangefs_d_revalidate,
143  };
144