1 /*
2 * linux/fs/fat/file.c
3 *
4 * Written 1992,1993 by Werner Almesberger
5 *
6 * regular file handling primitives for fat-based filesystems
7 */
8
9 #include <linux/sched.h>
10 #include <linux/locks.h>
11 #include <linux/fs.h>
12 #include <linux/msdos_fs.h>
13 #include <linux/errno.h>
14 #include <linux/fcntl.h>
15 #include <linux/stat.h>
16 #include <linux/string.h>
17 #include <linux/pagemap.h>
18 #include <linux/fat_cvf.h>
19
20 #include <asm/uaccess.h>
21 #include <asm/system.h>
22
23 #define PRINTK(x)
24 #define Printk(x) printk x
25
26 struct file_operations fat_file_operations = {
27 llseek: generic_file_llseek,
28 read: fat_file_read,
29 write: fat_file_write,
30 mmap: generic_file_mmap,
31 fsync: file_fsync,
32 };
33
34 struct inode_operations fat_file_inode_operations = {
35 truncate: fat_truncate,
36 setattr: fat_notify_change,
37 };
38
fat_file_read(struct file * filp,char * buf,size_t count,loff_t * ppos)39 ssize_t fat_file_read(
40 struct file *filp,
41 char *buf,
42 size_t count,
43 loff_t *ppos)
44 {
45 struct inode *inode = filp->f_dentry->d_inode;
46 return MSDOS_SB(inode->i_sb)->cvf_format
47 ->cvf_file_read(filp,buf,count,ppos);
48 }
49
50
fat_get_block(struct inode * inode,long iblock,struct buffer_head * bh_result,int create)51 int fat_get_block(struct inode *inode, long iblock, struct buffer_head *bh_result, int create)
52 {
53 struct super_block *sb = inode->i_sb;
54 unsigned long phys;
55
56 phys = fat_bmap(inode, iblock);
57 if (phys) {
58 bh_result->b_dev = inode->i_dev;
59 bh_result->b_blocknr = phys;
60 bh_result->b_state |= (1UL << BH_Mapped);
61 return 0;
62 }
63 if (!create)
64 return 0;
65 if (iblock << sb->s_blocksize_bits != MSDOS_I(inode)->mmu_private) {
66 BUG();
67 return -EIO;
68 }
69 if (!(iblock % MSDOS_SB(inode->i_sb)->cluster_size)) {
70 if (fat_add_cluster(inode) < 0)
71 return -ENOSPC;
72 }
73 MSDOS_I(inode)->mmu_private += sb->s_blocksize;
74 phys = fat_bmap(inode, iblock);
75 if (!phys)
76 BUG();
77 bh_result->b_dev = inode->i_dev;
78 bh_result->b_blocknr = phys;
79 bh_result->b_state |= (1UL << BH_Mapped);
80 bh_result->b_state |= (1UL << BH_New);
81 return 0;
82 }
83
fat_file_write(struct file * filp,const char * buf,size_t count,loff_t * ppos)84 ssize_t fat_file_write(
85 struct file *filp,
86 const char *buf,
87 size_t count,
88 loff_t *ppos)
89 {
90 struct inode *inode = filp->f_dentry->d_inode;
91 struct super_block *sb = inode->i_sb;
92 return MSDOS_SB(sb)->cvf_format
93 ->cvf_file_write(filp,buf,count,ppos);
94 }
95
default_fat_file_write(struct file * filp,const char * buf,size_t count,loff_t * ppos)96 ssize_t default_fat_file_write(
97 struct file *filp,
98 const char *buf,
99 size_t count,
100 loff_t *ppos)
101 {
102 struct inode *inode = filp->f_dentry->d_inode;
103 int retval;
104
105 retval = generic_file_write(filp, buf, count, ppos);
106 if (retval > 0) {
107 inode->i_mtime = inode->i_ctime = CURRENT_TIME;
108 MSDOS_I(inode)->i_attrs |= ATTR_ARCH;
109 mark_inode_dirty(inode);
110 }
111 return retval;
112 }
113
fat_truncate(struct inode * inode)114 void fat_truncate(struct inode *inode)
115 {
116 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
117 int cluster;
118
119 /* Why no return value? Surely the disk could fail... */
120 if (IS_RDONLY (inode))
121 return /* -EPERM */;
122 if (IS_IMMUTABLE(inode))
123 return /* -EPERM */;
124 cluster = 1 << sbi->cluster_bits;
125 /*
126 * This protects against truncating a file bigger than it was then
127 * trying to write into the hole.
128 */
129 if (MSDOS_I(inode)->mmu_private > inode->i_size)
130 MSDOS_I(inode)->mmu_private = inode->i_size;
131
132 fat_free(inode, (inode->i_size + (cluster - 1)) >> sbi->cluster_bits);
133 MSDOS_I(inode)->i_attrs |= ATTR_ARCH;
134 inode->i_ctime = inode->i_mtime = CURRENT_TIME;
135 mark_inode_dirty(inode);
136 }
137