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 <linux/pagemap.h>
  12 #include "coda_linux.h"
  13
  14 static inline int coda_fideq(struct CodaFid *fid1, struct CodaFid *fid2)
  15 {
  16         return memcmp(fid1, fid2, sizeof(*fid1)) == 0;
  17 }
  18
  19 static const struct inode_operations coda_symlink_inode_operations = {
  20         .readlink       = generic_readlink,
  21         .get_link       = page_get_link,
  22         .put_link       = page_put_link,
  23         .setattr        = coda_setattr,
  24 };
  25
  26 /* cnode.c */
  27 static void coda_fill_inode(struct inode *inode, struct coda_vattr *attr)
  28 {
  29         coda_vattr_to_iattr(inode, attr);
  30
  31         if (S_ISREG(inode->i_mode)) {
  32                 inode->i_op = &coda_file_inode_operations;
  33                 inode->i_fop = &coda_file_operations;
  34         } else if (S_ISDIR(inode->i_mode)) {
  35                 inode->i_op = &coda_dir_inode_operations;
  36                 inode->i_fop = &coda_dir_operations;
  37         } else if (S_ISLNK(inode->i_mode)) {
  38                 inode->i_op = &coda_symlink_inode_operations;
  39                 inode_nohighmem(inode);
  40                 inode->i_data.a_ops = &coda_symlink_aops;
  41                 inode->i_mapping = &inode->i_data;
  42         } else
  43                 init_special_inode(inode, inode->i_mode, huge_decode_dev(attr->va_rdev));
  44 }
  45
  46 static int coda_test_inode(struct inode *inode, void *data)
  47 {
  48         struct CodaFid *fid = (struct CodaFid *)data;
  49         struct coda_inode_info *cii = ITOC(inode);
  50         return coda_fideq(&cii->c_fid, fid);
  51 }
  52
  53 static int coda_set_inode(struct inode *inode, void *data)
  54 {
  55         struct CodaFid *fid = (struct CodaFid *)data;
  56         struct coda_inode_info *cii = ITOC(inode);
  57         cii->c_fid = *fid;
  58         return 0;
  59 }
  60
  61 struct inode * coda_iget(struct super_block * sb, struct CodaFid * fid,
  62                          struct coda_vattr * attr)
  63 {
  64         struct inode *inode;
  65         struct coda_inode_info *cii;
  66         unsigned long hash = coda_f2i(fid);
  67
  68         inode = iget5_locked(sb, hash, coda_test_inode, coda_set_inode, fid);
  69
  70         if (!inode)
  71                 return ERR_PTR(-ENOMEM);
  72
  73         if (inode->i_state & I_NEW) {
  74                 cii = ITOC(inode);
  75                 /* we still need to set i_ino for things like stat(2) */
  76                 inode->i_ino = hash;
  77                 /* inode is locked and unique, no need to grab cii->c_lock */
  78                 cii->c_mapcount = 0;
  79                 unlock_new_inode(inode);
  80         }
  81
  82         /* always replace the attributes, type might have changed */
  83         coda_fill_inode(inode, attr);
  84         return inode;
  85 }
  86
  87 /* this is effectively coda_iget:
  88    - get attributes (might be cached)
  89    - get the inode for the fid using vfs iget
  90    - link the two up if this is needed
  91    - fill in the attributes
  92 */
  93 struct inode *coda_cnode_make(struct CodaFid *fid, struct super_block *sb)
  94 {
  95         struct coda_vattr attr;
  96         struct inode *inode;
  97         int error;
  98
  99         /* We get inode numbers from Venus -- see venus source */
 100         error = venus_getattr(sb, fid, &attr);
 101         if (error)
 102                 return ERR_PTR(error);
 103
 104         inode = coda_iget(sb, fid, &attr);
 105         if (IS_ERR(inode))
 106                 pr_warn("%s: coda_iget failed\n", __func__);
 107         return inode;
 108 }
 109
 110
 111 /* Although we treat Coda file identifiers as immutable, there is one
 112  * special case for files created during a disconnection where they may
 113  * not be globally unique. When an identifier collision is detected we
 114  * first try to flush the cached inode from the kernel and finally
 115  * resort to renaming/rehashing in-place. Userspace remembers both old
 116  * and new values of the identifier to handle any in-flight upcalls.
 117  * The real solution is to use globally unique UUIDs as identifiers, but
 118  * retrofitting the existing userspace code for this is non-trivial. */
 119 void coda_replace_fid(struct inode *inode, struct CodaFid *oldfid,
 120                       struct CodaFid *newfid)
 121 {
 122         struct coda_inode_info *cii = ITOC(inode);
 123         unsigned long hash = coda_f2i(newfid);
 124
 125         BUG_ON(!coda_fideq(&cii->c_fid, oldfid));
 126
 127         /* replace fid and rehash inode */
 128         /* XXX we probably need to hold some lock here! */
 129         remove_inode_hash(inode);
 130         cii->c_fid = *newfid;
 131         inode->i_ino = hash;
 132         __insert_inode_hash(inode, hash);
 133 }
 134
 135 /* convert a fid to an inode. */
 136 struct inode *coda_fid_to_inode(struct CodaFid *fid, struct super_block *sb)
 137 {
 138         struct inode *inode;
 139         unsigned long hash = coda_f2i(fid);
 140
 141         if ( !sb ) {
 142                 pr_warn("%s: no sb!\n", __func__);
 143                 return NULL;
 144         }
 145
 146         inode = ilookup5(sb, hash, coda_test_inode, fid);
 147         if ( !inode )
 148                 return NULL;
 149
 150         /* we should never see newly created inodes because we intentionally
 151          * fail in the initialization callback */
 152         BUG_ON(inode->i_state & I_NEW);
 153
 154         return inode;
 155 }
 156
 157 /* the CONTROL inode is made without asking attributes from Venus */
 158 struct inode *coda_cnode_makectl(struct super_block *sb)
 159 {
 160         struct inode *inode = new_inode(sb);
 161         if (inode) {
 162                 inode->i_ino = CTL_INO;
 163                 inode->i_op = &coda_ioctl_inode_operations;
 164                 inode->i_fop = &coda_ioctl_operations;
 165                 inode->i_mode = 0444;
 166                 return inode;
 167         }
 168         return ERR_PTR(-ENOMEM);
 169 }
 170