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                 goto out_put_parent;
  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         strncpy(new_op->upcall.req.lookup.d_name,
  34                 dentry->d_name.name,
  35                 ORANGEFS_NAME_LEN);
  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         ret = 1;
  77 out_release_op:
  78         op_release(new_op);
  79 out_put_parent:
  80         dput(parent_dentry);
  81         return ret;
  82 out_drop:
  83         gossip_debug(GOSSIP_DCACHE_DEBUG, "%s:%s:%d revalidate failed\n",
  84             __FILE__, __func__, __LINE__);
  85         d_drop(dentry);
  86         goto out_release_op;
  87 }
  88
  89 /*
  90  * Verify that dentry is valid.
  91  *
  92  * Should return 1 if dentry can still be trusted, else 0.
  93  */
  94 static int orangefs_d_revalidate(struct dentry *dentry, unsigned int flags)
  95 {
  96         int ret;
  97
  98         if (flags & LOOKUP_RCU)
  99                 return -ECHILD;
 100
 101         gossip_debug(GOSSIP_DCACHE_DEBUG, "%s: called on dentry %p.\n",
 102                      __func__, dentry);
 103
 104         /* skip root handle lookups. */
 105         if (dentry->d_inode && is_root_handle(dentry->d_inode))
 106                 return 1;
 107
 108         /*
 109          * If this passes, the positive dentry still exists or the negative
 110          * dentry still does not exist.
 111          */
 112         if (!orangefs_revalidate_lookup(dentry)) {
 113                 d_drop(dentry);
 114                 return 0;
 115         }
 116
 117         /* We do not need to continue with negative dentries. */
 118         if (!dentry->d_inode)
 119                 goto out;
 120
 121         /* Now we must perform a getattr to validate the inode contents. */
 122
 123         ret = orangefs_inode_getattr(dentry->d_inode,
 124             ORANGEFS_ATTR_SYS_TYPE|ORANGEFS_ATTR_SYS_LNK_TARGET, 1);
 125         if (ret < 0) {
 126                 gossip_debug(GOSSIP_DCACHE_DEBUG, "%s:%s:%d getattr failure.\n",
 127                     __FILE__, __func__, __LINE__);
 128                 d_drop(dentry);
 129                 return 0;
 130         }
 131         if (ret == 0) {
 132                 d_drop(dentry);
 133                 return 0;
 134         }
 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 };