fs/orangefs/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. */
  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  */
  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 };