fs/hfs/sysdep.c

   1 /*
   2  * linux/fs/hfs/sysdep.c
   3  *
   4  * Copyright (C) 1996  Paul H. Hargrove
   5  * This file may be distributed under the terms of the GNU Public License.
   6  *
   7  * This file contains the code to do various system dependent things.
   8  *
   9  * "XXX" in a comment is a note to myself to consider changing something.
  10  *
  11  * In function preconditions the term "valid" applied to a pointer to
  12  * a structure means that the pointer is non-NULL and the structure it
  13  * points to has all fields initialized to consistent values.
  14  */
  15
  16 #include "hfs.h"
  17 #include <linux/hfs_fs_sb.h>
  18 #include <linux/hfs_fs_i.h>
  19 #include <linux/hfs_fs.h>
  20
  21 static int hfs_revalidate_dentry(struct dentry *, int);
  22 static int hfs_hash_dentry(struct dentry *, struct qstr *);
  23 static int hfs_compare_dentry(struct dentry *, struct qstr *, struct qstr *);
  24 static void hfs_dentry_iput(struct dentry *, struct inode *);
  25 struct dentry_operations hfs_dentry_operations =
  26 {
  27         hfs_revalidate_dentry,  /* d_revalidate(struct dentry *) */
  28         hfs_hash_dentry,        /* d_hash */
  29         hfs_compare_dentry,     /* d_compare */
  30         NULL,                   /* d_delete(struct dentry *) */
  31         NULL,                   /* d_release(struct dentry *) */
  32         hfs_dentry_iput         /* d_iput(struct dentry *, struct inode *) */
  33 };
  34
  35 /*
  36  * hfs_buffer_get()
  37  *
  38  * Return a buffer for the 'block'th block of the media.
  39  * If ('read'==0) then the buffer is not read from disk.
  40  */
  41 hfs_buffer hfs_buffer_get(hfs_sysmdb sys_mdb, int block, int read) {
  42         hfs_buffer tmp = HFS_BAD_BUFFER;
  43
  44         if (read) {
  45                 tmp = bread(sys_mdb->s_dev, block, HFS_SECTOR_SIZE);
  46         } else {
  47                 tmp = getblk(sys_mdb->s_dev, block, HFS_SECTOR_SIZE);
  48                 if (tmp) {
  49                         mark_buffer_uptodate(tmp, 1);
  50                 }
  51         }
  52         if (!tmp) {
  53                 hfs_error("hfs_fs: unable to read block 0x%08x from dev %s\n",
  54                           block, hfs_mdb_name(sys_mdb));
  55         }
  56
  57         return tmp;
  58 }
  59
  60 /* dentry case-handling: just lowercase everything */
  61
  62 /* hfs_strhash now uses the same hashing function as the dcache. */
  63 static int hfs_hash_dentry(struct dentry *dentry, struct qstr *this)
  64 {
  65         if (this->len > HFS_NAMELEN)
  66                 return 0;
  67
  68         this->hash = hfs_strhash(this->name, this->len);
  69         return 0;
  70 }
  71
  72 /* return 1 on failure and 0 on success */
  73 static int hfs_compare_dentry(struct dentry *dentry, struct qstr *a,
  74                               struct qstr *b)
  75 {
  76         if (a->len != b->len) return 1;
  77
  78         if (a->len > HFS_NAMELEN)
  79           return 1;
  80
  81         return !hfs_streq(a->name, a->len, b->name, b->len);
  82 }
  83
  84 static void hfs_dentry_iput(struct dentry *dentry, struct inode *inode)
  85 {
  86         struct hfs_cat_entry *entry = HFS_I(inode)->entry;
  87
  88         entry->sys_entry[HFS_ITYPE_TO_INT(HFS_ITYPE(inode->i_ino))] = NULL;
  89         iput(inode);
  90 }
  91
  92 static int hfs_revalidate_dentry(struct dentry *dentry, int flags)
  93 {
  94         struct inode *inode = dentry->d_inode;
  95         int diff;
  96
  97         /* fix up inode on a timezone change */
  98         if (inode &&
  99             (diff = (hfs_to_utc(0) - HFS_I(inode)->tz_secondswest))) {
 100                 inode->i_ctime += diff;
 101                 inode->i_atime += diff;
 102                 inode->i_mtime += diff;
 103                 HFS_I(inode)->tz_secondswest += diff;
 104         }
 105         return 1;
 106 }