fs/orangefs/dcache.c

   1 /*
   2  * (C) 2001 Clemson University and The University of Chicago
   3  *
   4  * See COPYING in top-level directory.
   5  */
   6
   7 /*
   8  *  Implementation of dentry (directory cache) functions.
   9  */
  10
  11 #include "protocol.h"
  12 #include "orangefs-kernel.h"
  13
  14 /* Returns 1 if dentry can still be trusted, else 0. */
  15 static int orangefs_revalidate_lookup(struct dentry *dentry)
  16 {
  17         struct dentry *parent_dentry = dget_parent(dentry);
  18         struct inode *parent_inode = parent_dentry->d_inode;
  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                 ret = -ENOMEM;
  30                 goto out_put_parent;
  31         }
  32
  33         new_op->upcall.req.lookup.sym_follow = ORANGEFS_LOOKUP_LINK_NO_FOLLOW;
  34         new_op->upcall.req.lookup.parent_refn = parent->refn;
  35         strncpy(new_op->upcall.req.lookup.d_name,
  36                 dentry->d_name.name,
  37                 ORANGEFS_NAME_MAX);
  38
  39         gossip_debug(GOSSIP_DCACHE_DEBUG,
  40                      "%s:%s:%d interrupt flag [%d]\n",
  41                      __FILE__,
  42                      __func__,
  43                      __LINE__,
  44                      get_interruptible_flag(parent_inode));
  45
  46         err = service_operation(new_op, "orangefs_lookup",
  47                         get_interruptible_flag(parent_inode));
  48
  49         /* Positive dentry: reject if error or not the same inode. */
  50         if (inode) {
  51                 if (err) {
  52                         gossip_debug(GOSSIP_DCACHE_DEBUG,
  53                             "%s:%s:%d lookup failure.\n",
  54                             __FILE__, __func__, __LINE__);
  55                         goto out_drop;
  56                 }
  57                 if (!match_handle(new_op->downcall.resp.lookup.refn.khandle,
  58                     inode)) {
  59                         gossip_debug(GOSSIP_DCACHE_DEBUG,
  60                             "%s:%s:%d no match.\n",
  61                             __FILE__, __func__, __LINE__);
  62                         goto out_drop;
  63                 }
  64
  65         /* Negative dentry: reject if success or error other than ENOENT. */
  66         } else {
  67                 gossip_debug(GOSSIP_DCACHE_DEBUG, "%s: negative dentry.\n",
  68                     __func__);
  69                 if (!err || err != -ENOENT) {
  70                         if (new_op->downcall.status != 0)
  71                                 gossip_debug(GOSSIP_DCACHE_DEBUG,
  72                                     "%s:%s:%d lookup failure.\n",
  73                                     __FILE__, __func__, __LINE__);
  74                         goto out_drop;
  75                 }
  76         }
  77
  78         orangefs_set_timeout(dentry);
  79         ret = 1;
  80 out_release_op:
  81         op_release(new_op);
  82 out_put_parent:
  83         dput(parent_dentry);
  84         return ret;
  85 out_drop:
  86         gossip_debug(GOSSIP_DCACHE_DEBUG, "%s:%s:%d revalidate failed\n",
  87             __FILE__, __func__, __LINE__);
  88         goto out_release_op;
  89 }
  90
  91 /*
  92  * Verify that dentry is valid.
  93  *
  94  * Should return 1 if dentry can still be trusted, else 0.
  95  */
  96 static int orangefs_d_revalidate(struct dentry *dentry, unsigned int flags)
  97 {
  98         int ret;
  99         unsigned long time = (unsigned long) dentry->d_fsdata;
 100
 101         if (time_before(jiffies, time))
 102                 return 1;
 103
 104         if (flags & LOOKUP_RCU)
 105                 return -ECHILD;
 106
 107         gossip_debug(GOSSIP_DCACHE_DEBUG, "%s: called on dentry %p.\n",
 108                      __func__, dentry);
 109
 110         /* skip root handle lookups. */
 111         if (dentry->d_inode && is_root_handle(dentry->d_inode))
 112                 return 1;
 113
 114         /*
 115          * If this passes, the positive dentry still exists or the negative
 116          * dentry still does not exist.
 117          */
 118         if (!orangefs_revalidate_lookup(dentry))
 119                 return 0;
 120
 121         /* We do not need to continue with negative dentries. */
 122         if (!dentry->d_inode)
 123                 goto out;
 124
 125         /* Now we must perform a getattr to validate the inode contents. */
 126
 127         ret = orangefs_inode_check_changed(dentry->d_inode);
 128         if (ret < 0) {
 129                 gossip_debug(GOSSIP_DCACHE_DEBUG, "%s:%s:%d getattr failure.\n",
 130                     __FILE__, __func__, __LINE__);
 131                 return 0;
 132         }
 133         if (ret == 0)
 134                 return 0;
 135
 136 out:
 137         gossip_debug(GOSSIP_DCACHE_DEBUG,
 138             "%s: negative dentry or positive dentry and inode valid.\n",
 139             __func__);
 140         return 1;
 141 }
 142
 143 const struct dentry_operations orangefs_dentry_operations = {
 144         .d_revalidate = orangefs_d_revalidate,
 145 };