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 General 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 #include <linux/smp_lock.h>
  21
  22 static int hfs_revalidate_dentry(struct dentry *, struct nameidata *);
  23 static int hfs_hash_dentry(struct dentry *, struct qstr *);
  24 static int hfs_compare_dentry(struct dentry *, struct qstr *, struct qstr *);
  25 static void hfs_dentry_iput(struct dentry *, struct inode *);
  26 struct dentry_operations hfs_dentry_operations =
  27 {
  28         .d_revalidate   = hfs_revalidate_dentry,
  29         .d_hash         = hfs_hash_dentry,
  30         .d_compare      = hfs_compare_dentry,
  31         .d_iput         = hfs_dentry_iput,
  32 };
  33
  34 /*
  35  * hfs_buffer_get()
  36  *
  37  * Return a buffer for the 'block'th block of the media.
  38  * If ('read'==0) then the buffer is not read from disk.
  39  */
  40 hfs_buffer hfs_buffer_get(hfs_sysmdb sys_mdb, int block, int read) {
  41         hfs_buffer tmp = HFS_BAD_BUFFER;
  42
  43         if (read) {
  44                 tmp = sb_bread(sys_mdb, block);
  45         } else {
  46                 tmp = sb_getblk(sys_mdb, block);
  47                 if (tmp) {
  48                         set_buffer_uptodate(tmp);
  49                 }
  50         }
  51         if (!tmp) {
  52                 hfs_error("hfs_fs: unable to read block 0x%08x from dev %s\n",
  53                           block, hfs_mdb_name(sys_mdb));
  54         }
  55
  56         return tmp;
  57 }
  58
  59 /* dentry case-handling: just lowercase everything */
  60
  61 /* hfs_strhash now uses the same hashing function as the dcache. */
  62 static int hfs_hash_dentry(struct dentry *dentry, struct qstr *this)
  63 {
  64         if (this->len > HFS_NAMELEN)
  65                 return 0;
  66
  67         this->hash = hfs_strhash(this->name, this->len);
  68         return 0;
  69 }
  70
  71 /* return 1 on failure and 0 on success */
  72 static int hfs_compare_dentry(struct dentry *dentry, struct qstr *a,
  73                               struct qstr *b)
  74 {
  75         if (a->len != b->len) return 1;
  76
  77         if (a->len > HFS_NAMELEN)
  78           return 1;
  79
  80         return !hfs_streq(a->name, a->len, b->name, b->len);
  81 }
  82
  83 static void hfs_dentry_iput(struct dentry *dentry, struct inode *inode)
  84 {
  85         struct hfs_cat_entry *entry = HFS_I(inode)->entry;
  86
  87         lock_kernel();
  88         entry->sys_entry[HFS_ITYPE_TO_INT(HFS_ITYPE(inode->i_ino))] = NULL;
  89         unlock_kernel();
  90         iput(inode);
  91 }
  92
  93 static int hfs_revalidate_dentry(struct dentry *dentry, struct nameidata *nd)
  94 {
  95         struct inode *inode = dentry->d_inode;
  96         int diff;
  97
  98         /* fix up inode on a timezone change */
  99         lock_kernel();
 100         if (inode &&
 101             (diff = (hfs_to_utc(0) - HFS_I(inode)->tz_secondswest))) {
 102                 inode->i_ctime.tv_sec += diff;
 103                 inode->i_atime.tv_sec += diff;
 104                 inode->i_mtime.tv_sec += diff;
 105                 HFS_I(inode)->tz_secondswest += diff;
 106         }
 107         unlock_kernel();
 108         return 1;
 109 }