fs/coda/cnode.c

   1 /* cnode related routines for the coda kernel code
   2    (C) 1996 Peter Braam
   3    */
   4
   5 #include <linux/types.h>
   6 #include <linux/string.h>
   7 #include <linux/time.h>
   8
   9 #include <linux/coda.h>
  10 #include <linux/coda_psdev.h>
  11 #include "coda_linux.h"
  12
  13 static inline int coda_fideq(struct CodaFid *fid1, struct CodaFid *fid2)
  14 {
  15         return memcmp(fid1, fid2, sizeof(*fid1)) == 0;
  16 }
  17
  18 static const struct inode_operations coda_symlink_inode_operations = {
  19         .readlink       = generic_readlink,
  20         .follow_link    = page_follow_link_light,
  21         .put_link       = page_put_link,
  22         .setattr        = coda_setattr,
  23 };
  24
  25 /* cnode.c */
  26 static void coda_fill_inode(struct inode *inode, struct coda_vattr *attr)
  27 {
  28         coda_vattr_to_iattr(inode, attr);
  29
  30         if (S_ISREG(inode->i_mode)) {
  31                 inode->i_op = &coda_file_inode_operations;
  32                 inode->i_fop = &coda_file_operations;
  33         } else if (S_ISDIR(inode->i_mode)) {
  34                 inode->i_op = &coda_dir_inode_operations;
  35                 inode->i_fop = &coda_dir_operations;
  36         } else if (S_ISLNK(inode->i_mode)) {
  37                 inode->i_op = &coda_symlink_inode_operations;
  38                 inode->i_data.a_ops = &coda_symlink_aops;
  39                 inode->i_mapping = &inode->i_data;
  40         } else
  41                 init_special_inode(inode, inode->i_mode, huge_decode_dev(attr->va_rdev));
  42 }
  43
  44 static int coda_test_inode(struct inode *inode, void *data)
  45 {
  46         struct CodaFid *fid = (struct CodaFid *)data;
  47         struct coda_inode_info *cii = ITOC(inode);
  48         return coda_fideq(&cii->c_fid, fid);
  49 }
  50
  51 static int coda_set_inode(struct inode *inode, void *data)
  52 {
  53         struct CodaFid *fid = (struct CodaFid *)data;
  54         struct coda_inode_info *cii = ITOC(inode);
  55         cii->c_fid = *fid;
  56         return 0;
  57 }
  58
  59 struct inode * coda_iget(struct super_block * sb, struct CodaFid * fid,
  60                          struct coda_vattr * attr)
  61 {
  62         struct inode *inode;
  63         struct coda_inode_info *cii;
  64         unsigned long hash = coda_f2i(fid);
  65
  66         inode = iget5_locked(sb, hash, coda_test_inode, coda_set_inode, fid);
  67
  68         if (!inode)
  69                 return ERR_PTR(-ENOMEM);
  70
  71         if (inode->i_state & I_NEW) {
  72                 cii = ITOC(inode);
  73                 /* we still need to set i_ino for things like stat(2) */
  74                 inode->i_ino = hash;
  75                 /* inode is locked and unique, no need to grab cii->c_lock */
  76                 cii->c_mapcount = 0;
  77                 unlock_new_inode(inode);
  78         }
  79
  80         /* always replace the attributes, type might have changed */
  81         coda_fill_inode(inode, attr);
  82         return inode;
  83 }
  84
  85 /* this is effectively coda_iget:
  86    - get attributes (might be cached)
  87    - get the inode for the fid using vfs iget
  88    - link the two up if this is needed
  89    - fill in the attributes
  90 */
  91 struct inode *coda_cnode_make(struct CodaFid *fid, struct super_block *sb)
  92 {
  93         struct coda_vattr attr;
  94         struct inode *inode;
  95         int error;
  96
  97         /* We get inode numbers from Venus -- see venus source */
  98         error = venus_getattr(sb, fid, &attr);
  99         if (error)
 100                 return ERR_PTR(error);
 101
 102         inode = coda_iget(sb, fid, &attr);
 103         if (IS_ERR(inode))
 104                 printk("coda_cnode_make: coda_iget failed\n");
 105         return inode;
 106 }
 107
 108
 109 /* Although we treat Coda file identifiers as immutable, there is one
 110  * special case for files created during a disconnection where they may
 111  * not be globally unique. When an identifier collision is detected we
 112  * first try to flush the cached inode from the kernel and finally
 113  * resort to renaming/rehashing in-place. Userspace remembers both old
 114  * and new values of the identifier to handle any in-flight upcalls.
 115  * The real solution is to use globally unique UUIDs as identifiers, but
 116  * retrofitting the existing userspace code for this is non-trivial. */
 117 void coda_replace_fid(struct inode *inode, struct CodaFid *oldfid,
 118                       struct CodaFid *newfid)
 119 {
 120         struct coda_inode_info *cii = ITOC(inode);
 121         unsigned long hash = coda_f2i(newfid);
 122
 123         BUG_ON(!coda_fideq(&cii->c_fid, oldfid));
 124
 125         /* replace fid and rehash inode */
 126         /* XXX we probably need to hold some lock here! */
 127         remove_inode_hash(inode);
 128         cii->c_fid = *newfid;
 129         inode->i_ino = hash;
 130         __insert_inode_hash(inode, hash);
 131 }
 132
 133 /* convert a fid to an inode. */
 134 struct inode *coda_fid_to_inode(struct CodaFid *fid, struct super_block *sb)
 135 {
 136         struct inode *inode;
 137         unsigned long hash = coda_f2i(fid);
 138
 139         if ( !sb ) {
 140                 printk("coda_fid_to_inode: no sb!\n");
 141                 return NULL;
 142         }
 143
 144         inode = ilookup5(sb, hash, coda_test_inode, fid);
 145         if ( !inode )
 146                 return NULL;
 147
 148         /* we should never see newly created inodes because we intentionally
 149          * fail in the initialization callback */
 150         BUG_ON(inode->i_state & I_NEW);
 151
 152         return inode;
 153 }
 154
 155 /* the CONTROL inode is made without asking attributes from Venus */
 156 struct inode *coda_cnode_makectl(struct super_block *sb)
 157 {
 158         struct inode *inode = new_inode(sb);
 159         if (inode) {
 160                 inode->i_ino = CTL_INO;
 161                 inode->i_op = &coda_ioctl_inode_operations;
 162                 inode->i_fop = &coda_ioctl_operations;
 163                 inode->i_mode = 0444;
 164                 return inode;
 165         }
 166         return ERR_PTR(-ENOMEM);
 167 }
 168