LXR linux/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
  13static inline int coda_fideq(struct CodaFid *fid1, struct CodaFid *fid2)
  14{
  15        return memcmp(fid1, fid2, sizeof(*fid1)) == 0;
  16}
  17
  18static 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 */
  26static 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
  44static 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
  51static 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
  59struct 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*/
  91struct 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. */
 117void 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. */
 134struct 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 */
 156struct 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
 169