dcache.c

  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 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;
 78out_release_op:
 79	op_release(new_op);
 80	return ret;
 81out_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 */
 92static 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
137const struct dentry_operations orangefs_dentry_operations = {
138	.d_revalidate = orangefs_d_revalidate,
139};