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If a dentry is deleted, then a dentry is recreated with the same handle but a different type (i.e. it was a file and now it's a symlink), then its a different inode. The check was backwards, so d_revalidate would not have noticed. Due to the design of the OrangeFS server, this is rather unlikely. It's also possible for the dentry to be deleted and recreated with the same type. This would be undetectable. It's a bit of a ship of Theseus. Signed-off-by: Martin Brandenburg <martin@omnibond.com> Signed-off-by: Mike Marshall <hubcap@omnibond.com>
142 lines
3.6 KiB
C
142 lines
3.6 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* (C) 2001 Clemson University and The University of Chicago
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*
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* See COPYING in top-level directory.
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*/
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/*
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* Implementation of dentry (directory cache) functions.
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*/
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#include "protocol.h"
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#include "orangefs-kernel.h"
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/* Returns 1 if dentry can still be trusted, else 0. */
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static int orangefs_revalidate_lookup(struct dentry *dentry)
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{
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struct dentry *parent_dentry = dget_parent(dentry);
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struct inode *parent_inode = parent_dentry->d_inode;
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struct orangefs_inode_s *parent = ORANGEFS_I(parent_inode);
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struct inode *inode = dentry->d_inode;
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struct orangefs_kernel_op_s *new_op;
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int ret = 0;
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int err = 0;
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gossip_debug(GOSSIP_DCACHE_DEBUG, "%s: attempting lookup.\n", __func__);
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new_op = op_alloc(ORANGEFS_VFS_OP_LOOKUP);
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if (!new_op)
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goto out_put_parent;
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new_op->upcall.req.lookup.sym_follow = ORANGEFS_LOOKUP_LINK_NO_FOLLOW;
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new_op->upcall.req.lookup.parent_refn = parent->refn;
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strncpy(new_op->upcall.req.lookup.d_name,
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dentry->d_name.name,
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ORANGEFS_NAME_MAX - 1);
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gossip_debug(GOSSIP_DCACHE_DEBUG,
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"%s:%s:%d interrupt flag [%d]\n",
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__FILE__,
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__func__,
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__LINE__,
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get_interruptible_flag(parent_inode));
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err = service_operation(new_op, "orangefs_lookup",
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get_interruptible_flag(parent_inode));
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/* Positive dentry: reject if error or not the same inode. */
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if (inode) {
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if (err) {
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gossip_debug(GOSSIP_DCACHE_DEBUG,
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"%s:%s:%d lookup failure.\n",
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__FILE__, __func__, __LINE__);
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goto out_drop;
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}
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if (!match_handle(new_op->downcall.resp.lookup.refn.khandle,
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inode)) {
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gossip_debug(GOSSIP_DCACHE_DEBUG,
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"%s:%s:%d no match.\n",
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__FILE__, __func__, __LINE__);
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goto out_drop;
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}
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/* Negative dentry: reject if success or error other than ENOENT. */
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} else {
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gossip_debug(GOSSIP_DCACHE_DEBUG, "%s: negative dentry.\n",
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__func__);
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if (!err || err != -ENOENT) {
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if (new_op->downcall.status != 0)
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gossip_debug(GOSSIP_DCACHE_DEBUG,
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"%s:%s:%d lookup failure.\n",
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__FILE__, __func__, __LINE__);
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goto out_drop;
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}
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}
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orangefs_set_timeout(dentry);
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ret = 1;
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out_release_op:
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op_release(new_op);
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out_put_parent:
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dput(parent_dentry);
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return ret;
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out_drop:
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gossip_debug(GOSSIP_DCACHE_DEBUG, "%s:%s:%d revalidate failed\n",
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__FILE__, __func__, __LINE__);
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goto out_release_op;
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}
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/*
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* Verify that dentry is valid.
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*
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* Should return 1 if dentry can still be trusted, else 0.
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*/
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static int orangefs_d_revalidate(struct dentry *dentry, unsigned int flags)
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{
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int ret;
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unsigned long time = (unsigned long) dentry->d_fsdata;
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if (time_before(jiffies, time))
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return 1;
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if (flags & LOOKUP_RCU)
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return -ECHILD;
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gossip_debug(GOSSIP_DCACHE_DEBUG, "%s: called on dentry %p.\n",
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__func__, dentry);
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/* skip root handle lookups. */
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if (dentry->d_inode && is_root_handle(dentry->d_inode))
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return 1;
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/*
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* If this passes, the positive dentry still exists or the negative
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* dentry still does not exist.
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*/
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if (!orangefs_revalidate_lookup(dentry))
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return 0;
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/* We do not need to continue with negative dentries. */
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if (!dentry->d_inode) {
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gossip_debug(GOSSIP_DCACHE_DEBUG,
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"%s: negative dentry or positive dentry and inode valid.\n",
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__func__);
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return 1;
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}
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/* Now we must perform a getattr to validate the inode contents. */
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ret = orangefs_inode_check_changed(dentry->d_inode);
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if (ret < 0) {
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gossip_debug(GOSSIP_DCACHE_DEBUG, "%s:%s:%d getattr failure.\n",
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__FILE__, __func__, __LINE__);
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return 0;
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}
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return !ret;
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}
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const struct dentry_operations orangefs_dentry_operations = {
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.d_revalidate = orangefs_d_revalidate,
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};
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