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	strscpy(new_op->upcall.req.lookup.d_name, dentry->d_name.name);
 37
 38	gossip_debug(GOSSIP_DCACHE_DEBUG,
 39		     "%s:%s:%d interrupt flag [%d]\n",
 40		     __FILE__,
 41		     __func__,
 42		     __LINE__,
 43		     get_interruptible_flag(parent_inode));
 44
 45	err = service_operation(new_op, "orangefs_lookup",
 46			get_interruptible_flag(parent_inode));
 47
 48	/* Positive dentry: reject if error or not the same inode. */
 49	if (inode) {
 50		if (err) {
 51			gossip_debug(GOSSIP_DCACHE_DEBUG,
 52			    "%s:%s:%d lookup failure.\n",
 53			    __FILE__, __func__, __LINE__);
 54			goto out_drop;
 55		}
 56		if (!match_handle(new_op->downcall.resp.lookup.refn.khandle,
 57		    inode)) {
 58			gossip_debug(GOSSIP_DCACHE_DEBUG,
 59			    "%s:%s:%d no match.\n",
 60			    __FILE__, __func__, __LINE__);
 61			goto out_drop;
 62		}
 63
 64	/* Negative dentry: reject if success or error other than ENOENT. */
 65	} else {
 66		gossip_debug(GOSSIP_DCACHE_DEBUG, "%s: negative dentry.\n",
 67		    __func__);
 68		if (!err || err != -ENOENT) {
 69			if (new_op->downcall.status != 0)
 70				gossip_debug(GOSSIP_DCACHE_DEBUG,
 71				    "%s:%s:%d lookup failure.\n",
 72				    __FILE__, __func__, __LINE__);
 73			goto out_drop;
 74		}
 75	}
 76
 77	orangefs_set_timeout(dentry);
 78	ret = 1;
 79out_release_op:
 80	op_release(new_op);
 81out_put_parent:
 82	dput(parent_dentry);
 83	return ret;
 84out_drop:
 85	gossip_debug(GOSSIP_DCACHE_DEBUG, "%s:%s:%d revalidate failed\n",
 86	    __FILE__, __func__, __LINE__);
 87	goto out_release_op;
 88}
 89
 90/*
 91 * Verify that dentry is valid.
 92 *
 93 * Should return 1 if dentry can still be trusted, else 0.
 94 */
 95static int orangefs_d_revalidate(struct dentry *dentry, unsigned int flags)
 96{
 97	int ret;
 98	unsigned long time = (unsigned long) dentry->d_fsdata;
 99
100	if (time_before(jiffies, time))
101		return 1;
102
103	if (flags & LOOKUP_RCU)
104		return -ECHILD;
105
106	gossip_debug(GOSSIP_DCACHE_DEBUG, "%s: called on dentry %p.\n",
107		     __func__, dentry);
108
109	/* skip root handle lookups. */
110	if (dentry->d_inode && is_root_handle(dentry->d_inode))
111		return 1;
112
113	/*
114	 * If this passes, the positive dentry still exists or the negative
115	 * dentry still does not exist.
116	 */
117	if (!orangefs_revalidate_lookup(dentry))
118		return 0;
119
120	/* We do not need to continue with negative dentries. */
121	if (!dentry->d_inode) {
122		gossip_debug(GOSSIP_DCACHE_DEBUG,
123		    "%s: negative dentry or positive dentry and inode valid.\n",
124		    __func__);
125		return 1;
126	}
127
128	/* Now we must perform a getattr to validate the inode contents. */
129
130	ret = orangefs_inode_check_changed(dentry->d_inode);
131	if (ret < 0) {
132		gossip_debug(GOSSIP_DCACHE_DEBUG, "%s:%s:%d getattr failure.\n",
133		    __FILE__, __func__, __LINE__);
134		return 0;
135	}
136	return !ret;
137}
138
139const struct dentry_operations orangefs_dentry_operations = {
140	.d_revalidate = orangefs_d_revalidate,
141};