1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
|
/*
* linux/fs/nfs/file.c
*
* Copyright (C) 1992 Rick Sladkey
*
* Changes Copyright (C) 1994 by Florian La Roche
* - Do not copy data too often around in the kernel.
* - In nfs_file_read the return value of kmalloc wasn't checked.
* - Put in a better version of read look-ahead buffering. Original idea
* and implementation by Wai S Kok elekokws@ee.nus.sg.
*
* Expire cache on write to a file by Wai S Kok (Oct 1994).
*
* Total rewrite of read side for new NFS buffer cache.. Linus.
*
* nfs regular file handling functions
*/
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/fcntl.h>
#include <linux/stat.h>
#include <linux/nfs_fs.h>
#include <linux/mm.h>
#include <linux/malloc.h>
#include <linux/pagemap.h>
#include <linux/lockd/bind.h>
#include <asm/segment.h>
#include <asm/system.h>
#define NFSDBG_FACILITY NFSDBG_FILE
static int nfs_file_mmap(struct file *, struct vm_area_struct *);
static ssize_t nfs_file_read(struct file *, char *, size_t, loff_t *);
static ssize_t nfs_file_write(struct file *, const char *, size_t, loff_t *);
static int nfs_file_flush(struct file *);
static int nfs_file_close(struct inode *, struct file *);
static int nfs_fsync(struct file *, struct dentry *dentry);
static struct file_operations nfs_file_operations = {
NULL, /* lseek - default */
nfs_file_read, /* read */
nfs_file_write, /* write */
NULL, /* readdir - bad */
NULL, /* select - default */
NULL, /* ioctl - default */
nfs_file_mmap, /* mmap */
NULL, /* no special open is needed */
nfs_file_flush, /* flush */
nfs_file_close, /* release */
nfs_fsync, /* fsync */
NULL, /* fasync */
NULL, /* check_media_change */
NULL, /* revalidate */
nfs_lock, /* lock */
};
struct inode_operations nfs_file_inode_operations = {
&nfs_file_operations, /* default file operations */
NULL, /* create */
NULL, /* lookup */
NULL, /* link */
NULL, /* unlink */
NULL, /* symlink */
NULL, /* mkdir */
NULL, /* rmdir */
NULL, /* mknod */
NULL, /* rename */
NULL, /* readlink */
NULL, /* follow_link */
nfs_readpage, /* readpage */
nfs_writepage, /* writepage */
NULL, /* bmap */
NULL, /* truncate */
NULL, /* permission */
NULL, /* smap */
nfs_updatepage, /* updatepage */
nfs_revalidate, /* revalidate */
};
/* Hack for future NFS swap support */
#ifndef IS_SWAPFILE
# define IS_SWAPFILE(inode) (0)
#endif
/*
* Sync the file..
*/
static int
nfs_file_close(struct inode *inode, struct file *file)
{
int status;
dfprintk(VFS, "nfs: close(%x/%ld)\n", inode->i_dev, inode->i_ino);
status = nfs_wb_all(inode);
if (!status)
status = nfs_write_error(inode);
return status;
}
/*
* Flush all dirty pages, and check for write errors.
*
* We should probably do this better - this does get called at every
* close, so we should probably just flush the changes that "this"
* file has done and report on only those.
*
* Right now we use the "flush everything" approach. Overkill, but
* works.
*/
static int
nfs_file_flush(struct file *file)
{
return nfs_file_close(file->f_dentry->d_inode, file);
}
static ssize_t
nfs_file_read(struct file * file, char * buf, size_t count, loff_t *ppos)
{
struct dentry * dentry = file->f_dentry;
ssize_t result;
dfprintk(VFS, "nfs: read(%s/%s, %lu@%lu)\n",
dentry->d_parent->d_name.name, dentry->d_name.name,
(unsigned long) count, (unsigned long) *ppos);
result = nfs_revalidate_inode(NFS_DSERVER(dentry), dentry);
if (!result)
result = generic_file_read(file, buf, count, ppos);
return result;
}
static int
nfs_file_mmap(struct file * file, struct vm_area_struct * vma)
{
struct dentry *dentry = file->f_dentry;
int status;
dfprintk(VFS, "nfs: mmap(%s/%s)\n",
dentry->d_parent->d_name.name, dentry->d_name.name);
status = nfs_revalidate_inode(NFS_DSERVER(dentry), dentry);
if (!status)
status = generic_file_mmap(file, vma);
return status;
}
/*
* Flush any dirty pages for this process, and check for write errors.
* The return status from this call provides a reliable indication of
* whether any write errors occurred for this process.
*/
static int
nfs_fsync(struct file *file, struct dentry *dentry)
{
struct inode *inode = dentry->d_inode;
int status;
dfprintk(VFS, "nfs: fsync(%x/%ld)\n", inode->i_dev, inode->i_ino);
status = nfs_wb_pid(inode, current->pid);
if (!status)
status = nfs_write_error(inode);
return status;
}
/*
* Write to a file (through the page cache).
*/
static ssize_t
nfs_file_write(struct file *file, const char *buf, size_t count, loff_t *ppos)
{
struct dentry * dentry = file->f_dentry;
struct inode * inode = dentry->d_inode;
ssize_t result;
dfprintk(VFS, "nfs: write(%s/%s(%ld), %lu@%lu)\n",
dentry->d_parent->d_name.name, dentry->d_name.name,
inode->i_ino, (unsigned long) count, (unsigned long) *ppos);
result = -EBUSY;
if (IS_SWAPFILE(inode))
goto out_swapfile;
result = nfs_revalidate_inode(NFS_DSERVER(dentry), dentry);
if (result)
goto out;
result = count;
if (!count)
goto out;
/* Check for an error from a previous async call */
result = nfs_write_error(inode);
if (!result)
result = generic_file_write(file, buf, count, ppos);
out:
return result;
out_swapfile:
printk(KERN_INFO "NFS: attempt to write to active swap file!\n");
goto out;
}
/*
* Lock a (portion of) a file
*/
int
nfs_lock(struct file *filp, int cmd, struct file_lock *fl)
{
struct inode * inode = filp->f_dentry->d_inode;
int status;
dprintk("NFS: nfs_lock(f=%4x/%ld, t=%x, fl=%x, r=%ld:%ld)\n",
inode->i_dev, inode->i_ino,
fl->fl_type, fl->fl_flags,
fl->fl_start, fl->fl_end);
if (!inode)
return -EINVAL;
/* No mandatory locks over NFS */
if ((inode->i_mode & (S_ISGID | S_IXGRP)) == S_ISGID)
return -ENOLCK;
/* Fake OK code if mounted without NLM support */
if (NFS_SERVER(inode)->flags & NFS_MOUNT_NONLM)
return 0;
/*
* No BSD flocks over NFS allowed.
* Note: we could try to fake a POSIX lock request here by
* using ((u32) filp | 0x80000000) or some such as the pid.
* Not sure whether that would be unique, though, or whether
* that would break in other places.
*/
if (!fl->fl_owner || (fl->fl_flags & (FL_POSIX|FL_BROKEN)) != FL_POSIX)
return -ENOLCK;
/*
* Flush all pending writes before doing anything
* with locks..
*/
status = nfs_wb_all(inode);
if (status < 0)
return status;
if ((status = nlmclnt_proc(inode, cmd, fl)) < 0)
return status;
/*
* Make sure we re-validate anything we've got cached.
* This makes locking act as a cache coherency point.
*/
NFS_CACHEINV(inode);
return 0;
}
|
