fs/coda/cnode.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* cnode related routines for the coda kernel code
   3    (C) 1996 Peter Braam
   4    */
   5
   6 #include <linux/types.h>
   7 #include <linux/string.h>
   8 #include <linux/time.h>
   9
  10 #include <linux/coda.h>
  11 #include <linux/pagemap.h>
  12 #include "coda_psdev.h"
  13 #include "coda_linux.h"
  14
  15 static inline int coda_fideq(struct CodaFid *fid1, struct CodaFid *fid2)
  16 {
  17         return memcmp(fid1, fid2, sizeof(*fid1)) == 0;
  18 }
  19
  20 static const struct inode_operations coda_symlink_inode_operations = {
  21         .get_link       = page_get_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_nohighmem(inode);
  39                 inode->i_data.a_ops = &coda_symlink_aops;
  40                 inode->i_mapping = &inode->i_data;
  41         } else
  42                 init_special_inode(inode, inode->i_mode, huge_decode_dev(attr->va_rdev));
  43 }
  44
  45 static int coda_test_inode(struct inode *inode, void *data)
  46 {
  47         struct CodaFid *fid = (struct CodaFid *)data;
  48         struct coda_inode_info *cii = ITOC(inode);
  49         return coda_fideq(&cii->c_fid, fid);
  50 }
  51
  52 static int coda_set_inode(struct inode *inode, void *data)
  53 {
  54         struct CodaFid *fid = (struct CodaFid *)data;
  55         struct coda_inode_info *cii = ITOC(inode);
  56         cii->c_fid = *fid;
  57         return 0;
  58 }
  59
  60 struct inode * coda_iget(struct super_block * sb, struct CodaFid * fid,
  61                          struct coda_vattr * attr)
  62 {
  63         struct inode *inode;
  64         struct coda_inode_info *cii;
  65         unsigned long hash = coda_f2i(fid);
  66         umode_t inode_type = coda_inode_type(attr);
  67
  68 retry:
  69         inode = iget5_locked(sb, hash, coda_test_inode, coda_set_inode, fid);
  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                 coda_fill_inode(inode, attr);
  80                 unlock_new_inode(inode);
  81         } else if ((inode->i_mode & S_IFMT) != inode_type) {
  82                 /* Inode has changed type, mark bad and grab a new one */
  83                 remove_inode_hash(inode);
  84                 coda_flag_inode(inode, C_PURGE);
  85                 iput(inode);
  86                 goto retry;
  87         }
  88         return inode;
  89 }
  90
  91 /* this is effectively coda_iget:
  92    - get attributes (might be cached)
  93    - get the inode for the fid using vfs iget
  94    - link the two up if this is needed
  95    - fill in the attributes
  96 */
  97 struct inode *coda_cnode_make(struct CodaFid *fid, struct super_block *sb)
  98 {
  99         struct coda_vattr attr;
 100         struct inode *inode;
 101         int error;
 102
 103         /* We get inode numbers from Venus -- see venus source */
 104         error = venus_getattr(sb, fid, &attr);
 105         if (error)
 106                 return ERR_PTR(error);
 107
 108         inode = coda_iget(sb, fid, &attr);
 109         if (IS_ERR(inode))
 110                 pr_warn("%s: coda_iget failed\n", __func__);
 111         return inode;
 112 }
 113
 114
 115 /* Although we treat Coda file identifiers as immutable, there is one
 116  * special case for files created during a disconnection where they may
 117  * not be globally unique. When an identifier collision is detected we
 118  * first try to flush the cached inode from the kernel and finally
 119  * resort to renaming/rehashing in-place. Userspace remembers both old
 120  * and new values of the identifier to handle any in-flight upcalls.
 121  * The real solution is to use globally unique UUIDs as identifiers, but
 122  * retrofitting the existing userspace code for this is non-trivial. */
 123 void coda_replace_fid(struct inode *inode, struct CodaFid *oldfid,
 124                       struct CodaFid *newfid)
 125 {
 126         struct coda_inode_info *cii = ITOC(inode);
 127         unsigned long hash = coda_f2i(newfid);
 128
 129         BUG_ON(!coda_fideq(&cii->c_fid, oldfid));
 130
 131         /* replace fid and rehash inode */
 132         /* XXX we probably need to hold some lock here! */
 133         remove_inode_hash(inode);
 134         cii->c_fid = *newfid;
 135         inode->i_ino = hash;
 136         __insert_inode_hash(inode, hash);
 137 }
 138
 139 /* convert a fid to an inode. */
 140 struct inode *coda_fid_to_inode(struct CodaFid *fid, struct super_block *sb)
 141 {
 142         struct inode *inode;
 143         unsigned long hash = coda_f2i(fid);
 144
 145         inode = ilookup5(sb, hash, coda_test_inode, fid);
 146         if ( !inode )
 147                 return NULL;
 148
 149         /* we should never see newly created inodes because we intentionally
 150          * fail in the initialization callback */
 151         BUG_ON(inode->i_state & I_NEW);
 152
 153         return inode;
 154 }
 155
 156 struct coda_file_info *coda_ftoc(struct file *file)
 157 {
 158         struct coda_file_info *cfi = file->private_data;
 159
 160         BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
 161
 162         return cfi;
 163
 164 }
 165
 166 /* the CONTROL inode is made without asking attributes from Venus */
 167 struct inode *coda_cnode_makectl(struct super_block *sb)
 168 {
 169         struct inode *inode = new_inode(sb);
 170         if (inode) {
 171                 inode->i_ino = CTL_INO;
 172                 inode->i_op = &coda_ioctl_inode_operations;
 173                 inode->i_fop = &coda_ioctl_operations;
 174                 inode->i_mode = 0444;
 175                 return inode;
 176         }
 177         return ERR_PTR(-ENOMEM);
 178 }
 179