CRED: Wrap current->cred and a few other accessors
[linux-2.6.git] / fs / smbfs / file.c
1 /*
2  *  file.c
3  *
4  *  Copyright (C) 1995, 1996, 1997 by Paal-Kr. Engstad and Volker Lendecke
5  *  Copyright (C) 1997 by Volker Lendecke
6  *
7  *  Please add a note about your changes to smbfs in the ChangeLog file.
8  */
9
10 #include <linux/time.h>
11 #include <linux/kernel.h>
12 #include <linux/errno.h>
13 #include <linux/fcntl.h>
14 #include <linux/stat.h>
15 #include <linux/mm.h>
16 #include <linux/slab.h>
17 #include <linux/pagemap.h>
18 #include <linux/smp_lock.h>
19 #include <linux/net.h>
20 #include <linux/aio.h>
21
22 #include <asm/uaccess.h>
23 #include <asm/system.h>
24
25 #include <linux/smbno.h>
26 #include <linux/smb_fs.h>
27
28 #include "smb_debug.h"
29 #include "proto.h"
30
31 static int
32 smb_fsync(struct file *file, struct dentry * dentry, int datasync)
33 {
34         struct smb_sb_info *server = server_from_dentry(dentry);
35         int result;
36
37         VERBOSE("sync file %s/%s\n", DENTRY_PATH(dentry));
38
39         /*
40          * The VFS will writepage() all dirty pages for us, but we
41          * should send a SMBflush to the server, letting it know that
42          * we want things synchronized with actual storage.
43          *
44          * Note: this function requires all pages to have been written already
45          *       (should be ok with writepage_sync)
46          */
47         result = smb_proc_flush(server, SMB_I(dentry->d_inode)->fileid);
48         return result;
49 }
50
51 /*
52  * Read a page synchronously.
53  */
54 static int
55 smb_readpage_sync(struct dentry *dentry, struct page *page)
56 {
57         char *buffer = kmap(page);
58         loff_t offset = (loff_t)page->index << PAGE_CACHE_SHIFT;
59         struct smb_sb_info *server = server_from_dentry(dentry);
60         unsigned int rsize = smb_get_rsize(server);
61         int count = PAGE_SIZE;
62         int result;
63
64         VERBOSE("file %s/%s, count=%d@%Ld, rsize=%d\n",
65                 DENTRY_PATH(dentry), count, offset, rsize);
66
67         result = smb_open(dentry, SMB_O_RDONLY);
68         if (result < 0)
69                 goto io_error;
70
71         do {
72                 if (count < rsize)
73                         rsize = count;
74
75                 result = server->ops->read(dentry->d_inode,offset,rsize,buffer);
76                 if (result < 0)
77                         goto io_error;
78
79                 count -= result;
80                 offset += result;
81                 buffer += result;
82                 dentry->d_inode->i_atime =
83                         current_fs_time(dentry->d_inode->i_sb);
84                 if (result < rsize)
85                         break;
86         } while (count);
87
88         memset(buffer, 0, count);
89         flush_dcache_page(page);
90         SetPageUptodate(page);
91         result = 0;
92
93 io_error:
94         kunmap(page);
95         unlock_page(page);
96         return result;
97 }
98
99 /*
100  * We are called with the page locked and we unlock it when done.
101  */
102 static int
103 smb_readpage(struct file *file, struct page *page)
104 {
105         int             error;
106         struct dentry  *dentry = file->f_path.dentry;
107
108         page_cache_get(page);
109         error = smb_readpage_sync(dentry, page);
110         page_cache_release(page);
111         return error;
112 }
113
114 /*
115  * Write a page synchronously.
116  * Offset is the data offset within the page.
117  */
118 static int
119 smb_writepage_sync(struct inode *inode, struct page *page,
120                    unsigned long pageoffset, unsigned int count)
121 {
122         loff_t offset;
123         char *buffer = kmap(page) + pageoffset;
124         struct smb_sb_info *server = server_from_inode(inode);
125         unsigned int wsize = smb_get_wsize(server);
126         int ret = 0;
127
128         offset = ((loff_t)page->index << PAGE_CACHE_SHIFT) + pageoffset;
129         VERBOSE("file ino=%ld, fileid=%d, count=%d@%Ld, wsize=%d\n",
130                 inode->i_ino, SMB_I(inode)->fileid, count, offset, wsize);
131
132         do {
133                 int write_ret;
134
135                 if (count < wsize)
136                         wsize = count;
137
138                 write_ret = server->ops->write(inode, offset, wsize, buffer);
139                 if (write_ret < 0) {
140                         PARANOIA("failed write, wsize=%d, write_ret=%d\n",
141                                  wsize, write_ret);
142                         ret = write_ret;
143                         break;
144                 }
145                 /* N.B. what if result < wsize?? */
146 #ifdef SMBFS_PARANOIA
147                 if (write_ret < wsize)
148                         PARANOIA("short write, wsize=%d, write_ret=%d\n",
149                                  wsize, write_ret);
150 #endif
151                 buffer += wsize;
152                 offset += wsize;
153                 count -= wsize;
154                 /*
155                  * Update the inode now rather than waiting for a refresh.
156                  */
157                 inode->i_mtime = inode->i_atime = current_fs_time(inode->i_sb);
158                 SMB_I(inode)->flags |= SMB_F_LOCALWRITE;
159                 if (offset > inode->i_size)
160                         inode->i_size = offset;
161         } while (count);
162
163         kunmap(page);
164         return ret;
165 }
166
167 /*
168  * Write a page to the server. This will be used for NFS swapping only
169  * (for now), and we currently do this synchronously only.
170  *
171  * We are called with the page locked and we unlock it when done.
172  */
173 static int
174 smb_writepage(struct page *page, struct writeback_control *wbc)
175 {
176         struct address_space *mapping = page->mapping;
177         struct inode *inode;
178         unsigned long end_index;
179         unsigned offset = PAGE_CACHE_SIZE;
180         int err;
181
182         BUG_ON(!mapping);
183         inode = mapping->host;
184         BUG_ON(!inode);
185
186         end_index = inode->i_size >> PAGE_CACHE_SHIFT;
187
188         /* easy case */
189         if (page->index < end_index)
190                 goto do_it;
191         /* things got complicated... */
192         offset = inode->i_size & (PAGE_CACHE_SIZE-1);
193         /* OK, are we completely out? */
194         if (page->index >= end_index+1 || !offset)
195                 return 0; /* truncated - don't care */
196 do_it:
197         page_cache_get(page);
198         err = smb_writepage_sync(inode, page, 0, offset);
199         SetPageUptodate(page);
200         unlock_page(page);
201         page_cache_release(page);
202         return err;
203 }
204
205 static int
206 smb_updatepage(struct file *file, struct page *page, unsigned long offset,
207                unsigned int count)
208 {
209         struct dentry *dentry = file->f_path.dentry;
210
211         DEBUG1("(%s/%s %d@%lld)\n", DENTRY_PATH(dentry), count,
212                 ((unsigned long long)page->index << PAGE_CACHE_SHIFT) + offset);
213
214         return smb_writepage_sync(dentry->d_inode, page, offset, count);
215 }
216
217 static ssize_t
218 smb_file_aio_read(struct kiocb *iocb, const struct iovec *iov,
219                         unsigned long nr_segs, loff_t pos)
220 {
221         struct file * file = iocb->ki_filp;
222         struct dentry * dentry = file->f_path.dentry;
223         ssize_t status;
224
225         VERBOSE("file %s/%s, count=%lu@%lu\n", DENTRY_PATH(dentry),
226                 (unsigned long) iocb->ki_left, (unsigned long) pos);
227
228         status = smb_revalidate_inode(dentry);
229         if (status) {
230                 PARANOIA("%s/%s validation failed, error=%Zd\n",
231                          DENTRY_PATH(dentry), status);
232                 goto out;
233         }
234
235         VERBOSE("before read, size=%ld, flags=%x, atime=%ld\n",
236                 (long)dentry->d_inode->i_size,
237                 dentry->d_inode->i_flags, dentry->d_inode->i_atime.tv_sec);
238
239         status = generic_file_aio_read(iocb, iov, nr_segs, pos);
240 out:
241         return status;
242 }
243
244 static int
245 smb_file_mmap(struct file * file, struct vm_area_struct * vma)
246 {
247         struct dentry * dentry = file->f_path.dentry;
248         int     status;
249
250         VERBOSE("file %s/%s, address %lu - %lu\n",
251                 DENTRY_PATH(dentry), vma->vm_start, vma->vm_end);
252
253         status = smb_revalidate_inode(dentry);
254         if (status) {
255                 PARANOIA("%s/%s validation failed, error=%d\n",
256                          DENTRY_PATH(dentry), status);
257                 goto out;
258         }
259         status = generic_file_mmap(file, vma);
260 out:
261         return status;
262 }
263
264 static ssize_t
265 smb_file_splice_read(struct file *file, loff_t *ppos,
266                      struct pipe_inode_info *pipe, size_t count,
267                      unsigned int flags)
268 {
269         struct dentry *dentry = file->f_path.dentry;
270         ssize_t status;
271
272         VERBOSE("file %s/%s, pos=%Ld, count=%lu\n",
273                 DENTRY_PATH(dentry), *ppos, count);
274
275         status = smb_revalidate_inode(dentry);
276         if (status) {
277                 PARANOIA("%s/%s validation failed, error=%Zd\n",
278                          DENTRY_PATH(dentry), status);
279                 goto out;
280         }
281         status = generic_file_splice_read(file, ppos, pipe, count, flags);
282 out:
283         return status;
284 }
285
286 /*
287  * This does the "real" work of the write. The generic routine has
288  * allocated the page, locked it, done all the page alignment stuff
289  * calculations etc. Now we should just copy the data from user
290  * space and write it back to the real medium..
291  *
292  * If the writer ends up delaying the write, the writer needs to
293  * increment the page use counts until he is done with the page.
294  */
295 static int smb_write_begin(struct file *file, struct address_space *mapping,
296                         loff_t pos, unsigned len, unsigned flags,
297                         struct page **pagep, void **fsdata)
298 {
299         pgoff_t index = pos >> PAGE_CACHE_SHIFT;
300         *pagep = __grab_cache_page(mapping, index);
301         if (!*pagep)
302                 return -ENOMEM;
303         return 0;
304 }
305
306 static int smb_write_end(struct file *file, struct address_space *mapping,
307                         loff_t pos, unsigned len, unsigned copied,
308                         struct page *page, void *fsdata)
309 {
310         int status;
311         unsigned offset = pos & (PAGE_CACHE_SIZE - 1);
312
313         lock_kernel();
314         status = smb_updatepage(file, page, offset, copied);
315         unlock_kernel();
316
317         if (!status) {
318                 if (!PageUptodate(page) && copied == PAGE_CACHE_SIZE)
319                         SetPageUptodate(page);
320                 status = copied;
321         }
322
323         unlock_page(page);
324         page_cache_release(page);
325
326         return status;
327 }
328
329 const struct address_space_operations smb_file_aops = {
330         .readpage = smb_readpage,
331         .writepage = smb_writepage,
332         .write_begin = smb_write_begin,
333         .write_end = smb_write_end,
334 };
335
336 /* 
337  * Write to a file (through the page cache).
338  */
339 static ssize_t
340 smb_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
341                                unsigned long nr_segs, loff_t pos)
342 {
343         struct file * file = iocb->ki_filp;
344         struct dentry * dentry = file->f_path.dentry;
345         ssize_t result;
346
347         VERBOSE("file %s/%s, count=%lu@%lu\n",
348                 DENTRY_PATH(dentry),
349                 (unsigned long) iocb->ki_left, (unsigned long) pos);
350
351         result = smb_revalidate_inode(dentry);
352         if (result) {
353                 PARANOIA("%s/%s validation failed, error=%Zd\n",
354                          DENTRY_PATH(dentry), result);
355                 goto out;
356         }
357
358         result = smb_open(dentry, SMB_O_WRONLY);
359         if (result)
360                 goto out;
361
362         if (iocb->ki_left > 0) {
363                 result = generic_file_aio_write(iocb, iov, nr_segs, pos);
364                 VERBOSE("pos=%ld, size=%ld, mtime=%ld, atime=%ld\n",
365                         (long) file->f_pos, (long) dentry->d_inode->i_size,
366                         dentry->d_inode->i_mtime.tv_sec,
367                         dentry->d_inode->i_atime.tv_sec);
368         }
369 out:
370         return result;
371 }
372
373 static int
374 smb_file_open(struct inode *inode, struct file * file)
375 {
376         int result;
377         struct dentry *dentry = file->f_path.dentry;
378         int smb_mode = (file->f_mode & O_ACCMODE) - 1;
379
380         lock_kernel();
381         result = smb_open(dentry, smb_mode);
382         if (result)
383                 goto out;
384         SMB_I(inode)->openers++;
385 out:
386         unlock_kernel();
387         return result;
388 }
389
390 static int
391 smb_file_release(struct inode *inode, struct file * file)
392 {
393         lock_kernel();
394         if (!--SMB_I(inode)->openers) {
395                 /* We must flush any dirty pages now as we won't be able to
396                    write anything after close. mmap can trigger this.
397                    "openers" should perhaps include mmap'ers ... */
398                 filemap_write_and_wait(inode->i_mapping);
399                 smb_close(inode);
400         }
401         unlock_kernel();
402         return 0;
403 }
404
405 /*
406  * Check whether the required access is compatible with
407  * an inode's permission. SMB doesn't recognize superuser
408  * privileges, so we need our own check for this.
409  */
410 static int
411 smb_file_permission(struct inode *inode, int mask)
412 {
413         int mode = inode->i_mode;
414         int error = 0;
415
416         VERBOSE("mode=%x, mask=%x\n", mode, mask);
417
418         /* Look at user permissions */
419         mode >>= 6;
420         if (mask & ~mode & (MAY_READ | MAY_WRITE | MAY_EXEC))
421                 error = -EACCES;
422         return error;
423 }
424
425 static loff_t smb_remote_llseek(struct file *file, loff_t offset, int origin)
426 {
427         loff_t ret;
428         lock_kernel();
429         ret = generic_file_llseek_unlocked(file, offset, origin);
430         unlock_kernel();
431         return ret;
432 }
433
434 const struct file_operations smb_file_operations =
435 {
436         .llseek         = smb_remote_llseek,
437         .read           = do_sync_read,
438         .aio_read       = smb_file_aio_read,
439         .write          = do_sync_write,
440         .aio_write      = smb_file_aio_write,
441         .ioctl          = smb_ioctl,
442         .mmap           = smb_file_mmap,
443         .open           = smb_file_open,
444         .release        = smb_file_release,
445         .fsync          = smb_fsync,
446         .splice_read    = smb_file_splice_read,
447 };
448
449 const struct inode_operations smb_file_inode_operations =
450 {
451         .permission     = smb_file_permission,
452         .getattr        = smb_getattr,
453         .setattr        = smb_notify_change,
454 };