~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

TOMOYO Linux Cross Reference
Linux/fs/9p/vfs_addr.c

Version: ~ [ linux-5.13-rc5 ] ~ [ linux-5.12.9 ] ~ [ linux-5.11.22 ] ~ [ linux-5.10.42 ] ~ [ linux-5.9.16 ] ~ [ linux-5.8.18 ] ~ [ linux-5.7.19 ] ~ [ linux-5.6.19 ] ~ [ linux-5.5.19 ] ~ [ linux-5.4.124 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.193 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.235 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.271 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.271 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.18.140 ] ~ [ linux-3.16.85 ] ~ [ linux-3.14.79 ] ~ [ linux-3.12.74 ] ~ [ linux-3.10.108 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  1 // SPDX-License-Identifier: GPL-2.0-only
  2 /*
  3  *  linux/fs/9p/vfs_addr.c
  4  *
  5  * This file contians vfs address (mmap) ops for 9P2000.
  6  *
  7  *  Copyright (C) 2005 by Eric Van Hensbergen <ericvh@gmail.com>
  8  *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
  9  */
 10 
 11 #include <linux/module.h>
 12 #include <linux/errno.h>
 13 #include <linux/fs.h>
 14 #include <linux/file.h>
 15 #include <linux/stat.h>
 16 #include <linux/string.h>
 17 #include <linux/inet.h>
 18 #include <linux/pagemap.h>
 19 #include <linux/idr.h>
 20 #include <linux/sched.h>
 21 #include <linux/uio.h>
 22 #include <linux/bvec.h>
 23 #include <net/9p/9p.h>
 24 #include <net/9p/client.h>
 25 
 26 #include "v9fs.h"
 27 #include "v9fs_vfs.h"
 28 #include "cache.h"
 29 #include "fid.h"
 30 
 31 /**
 32  * v9fs_fid_readpage - read an entire page in from 9P
 33  *
 34  * @fid: fid being read
 35  * @page: structure to page
 36  *
 37  */
 38 static int v9fs_fid_readpage(void *data, struct page *page)
 39 {
 40         struct p9_fid *fid = data;
 41         struct inode *inode = page->mapping->host;
 42         struct bio_vec bvec = {.bv_page = page, .bv_len = PAGE_SIZE};
 43         struct iov_iter to;
 44         int retval, err;
 45 
 46         p9_debug(P9_DEBUG_VFS, "\n");
 47 
 48         BUG_ON(!PageLocked(page));
 49 
 50         retval = v9fs_readpage_from_fscache(inode, page);
 51         if (retval == 0)
 52                 return retval;
 53 
 54         iov_iter_bvec(&to, READ, &bvec, 1, PAGE_SIZE);
 55 
 56         retval = p9_client_read(fid, page_offset(page), &to, &err);
 57         if (err) {
 58                 v9fs_uncache_page(inode, page);
 59                 retval = err;
 60                 goto done;
 61         }
 62 
 63         zero_user(page, retval, PAGE_SIZE - retval);
 64         flush_dcache_page(page);
 65         SetPageUptodate(page);
 66 
 67         v9fs_readpage_to_fscache(inode, page);
 68         retval = 0;
 69 
 70 done:
 71         unlock_page(page);
 72         return retval;
 73 }
 74 
 75 /**
 76  * v9fs_vfs_readpage - read an entire page in from 9P
 77  *
 78  * @filp: file being read
 79  * @page: structure to page
 80  *
 81  */
 82 
 83 static int v9fs_vfs_readpage(struct file *filp, struct page *page)
 84 {
 85         return v9fs_fid_readpage(filp->private_data, page);
 86 }
 87 
 88 /**
 89  * v9fs_vfs_readpages - read a set of pages from 9P
 90  *
 91  * @filp: file being read
 92  * @mapping: the address space
 93  * @pages: list of pages to read
 94  * @nr_pages: count of pages to read
 95  *
 96  */
 97 
 98 static int v9fs_vfs_readpages(struct file *filp, struct address_space *mapping,
 99                              struct list_head *pages, unsigned nr_pages)
100 {
101         int ret = 0;
102         struct inode *inode;
103 
104         inode = mapping->host;
105         p9_debug(P9_DEBUG_VFS, "inode: %p file: %p\n", inode, filp);
106 
107         ret = v9fs_readpages_from_fscache(inode, mapping, pages, &nr_pages);
108         if (ret == 0)
109                 return ret;
110 
111         ret = read_cache_pages(mapping, pages, v9fs_fid_readpage,
112                         filp->private_data);
113         p9_debug(P9_DEBUG_VFS, "  = %d\n", ret);
114         return ret;
115 }
116 
117 /**
118  * v9fs_release_page - release the private state associated with a page
119  *
120  * Returns 1 if the page can be released, false otherwise.
121  */
122 
123 static int v9fs_release_page(struct page *page, gfp_t gfp)
124 {
125         if (PagePrivate(page))
126                 return 0;
127         return v9fs_fscache_release_page(page, gfp);
128 }
129 
130 /**
131  * v9fs_invalidate_page - Invalidate a page completely or partially
132  *
133  * @page: structure to page
134  * @offset: offset in the page
135  */
136 
137 static void v9fs_invalidate_page(struct page *page, unsigned int offset,
138                                  unsigned int length)
139 {
140         /*
141          * If called with zero offset, we should release
142          * the private state assocated with the page
143          */
144         if (offset == 0 && length == PAGE_SIZE)
145                 v9fs_fscache_invalidate_page(page);
146 }
147 
148 static int v9fs_vfs_writepage_locked(struct page *page)
149 {
150         struct inode *inode = page->mapping->host;
151         struct v9fs_inode *v9inode = V9FS_I(inode);
152         loff_t size = i_size_read(inode);
153         struct iov_iter from;
154         struct bio_vec bvec;
155         int err, len;
156 
157         if (page->index == size >> PAGE_SHIFT)
158                 len = size & ~PAGE_MASK;
159         else
160                 len = PAGE_SIZE;
161 
162         bvec.bv_page = page;
163         bvec.bv_offset = 0;
164         bvec.bv_len = len;
165         iov_iter_bvec(&from, WRITE, &bvec, 1, len);
166 
167         /* We should have writeback_fid always set */
168         BUG_ON(!v9inode->writeback_fid);
169 
170         set_page_writeback(page);
171 
172         p9_client_write(v9inode->writeback_fid, page_offset(page), &from, &err);
173 
174         end_page_writeback(page);
175         return err;
176 }
177 
178 static int v9fs_vfs_writepage(struct page *page, struct writeback_control *wbc)
179 {
180         int retval;
181 
182         p9_debug(P9_DEBUG_VFS, "page %p\n", page);
183 
184         retval = v9fs_vfs_writepage_locked(page);
185         if (retval < 0) {
186                 if (retval == -EAGAIN) {
187                         redirty_page_for_writepage(wbc, page);
188                         retval = 0;
189                 } else {
190                         SetPageError(page);
191                         mapping_set_error(page->mapping, retval);
192                 }
193         } else
194                 retval = 0;
195 
196         unlock_page(page);
197         return retval;
198 }
199 
200 /**
201  * v9fs_launder_page - Writeback a dirty page
202  * Returns 0 on success.
203  */
204 
205 static int v9fs_launder_page(struct page *page)
206 {
207         int retval;
208         struct inode *inode = page->mapping->host;
209 
210         v9fs_fscache_wait_on_page_write(inode, page);
211         if (clear_page_dirty_for_io(page)) {
212                 retval = v9fs_vfs_writepage_locked(page);
213                 if (retval)
214                         return retval;
215         }
216         return 0;
217 }
218 
219 /**
220  * v9fs_direct_IO - 9P address space operation for direct I/O
221  * @iocb: target I/O control block
222  *
223  * The presence of v9fs_direct_IO() in the address space ops vector
224  * allowes open() O_DIRECT flags which would have failed otherwise.
225  *
226  * In the non-cached mode, we shunt off direct read and write requests before
227  * the VFS gets them, so this method should never be called.
228  *
229  * Direct IO is not 'yet' supported in the cached mode. Hence when
230  * this routine is called through generic_file_aio_read(), the read/write fails
231  * with an error.
232  *
233  */
234 static ssize_t
235 v9fs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
236 {
237         struct file *file = iocb->ki_filp;
238         loff_t pos = iocb->ki_pos;
239         ssize_t n;
240         int err = 0;
241         if (iov_iter_rw(iter) == WRITE) {
242                 n = p9_client_write(file->private_data, pos, iter, &err);
243                 if (n) {
244                         struct inode *inode = file_inode(file);
245                         loff_t i_size = i_size_read(inode);
246                         if (pos + n > i_size)
247                                 inode_add_bytes(inode, pos + n - i_size);
248                 }
249         } else {
250                 n = p9_client_read(file->private_data, pos, iter, &err);
251         }
252         return n ? n : err;
253 }
254 
255 static int v9fs_write_begin(struct file *filp, struct address_space *mapping,
256                             loff_t pos, unsigned len, unsigned flags,
257                             struct page **pagep, void **fsdata)
258 {
259         int retval = 0;
260         struct page *page;
261         struct v9fs_inode *v9inode;
262         pgoff_t index = pos >> PAGE_SHIFT;
263         struct inode *inode = mapping->host;
264 
265 
266         p9_debug(P9_DEBUG_VFS, "filp %p, mapping %p\n", filp, mapping);
267 
268         v9inode = V9FS_I(inode);
269 start:
270         page = grab_cache_page_write_begin(mapping, index, flags);
271         if (!page) {
272                 retval = -ENOMEM;
273                 goto out;
274         }
275         BUG_ON(!v9inode->writeback_fid);
276         if (PageUptodate(page))
277                 goto out;
278 
279         if (len == PAGE_SIZE)
280                 goto out;
281 
282         retval = v9fs_fid_readpage(v9inode->writeback_fid, page);
283         put_page(page);
284         if (!retval)
285                 goto start;
286 out:
287         *pagep = page;
288         return retval;
289 }
290 
291 static int v9fs_write_end(struct file *filp, struct address_space *mapping,
292                           loff_t pos, unsigned len, unsigned copied,
293                           struct page *page, void *fsdata)
294 {
295         loff_t last_pos = pos + copied;
296         struct inode *inode = page->mapping->host;
297 
298         p9_debug(P9_DEBUG_VFS, "filp %p, mapping %p\n", filp, mapping);
299 
300         if (!PageUptodate(page)) {
301                 if (unlikely(copied < len)) {
302                         copied = 0;
303                         goto out;
304                 } else if (len == PAGE_SIZE) {
305                         SetPageUptodate(page);
306                 }
307         }
308         /*
309          * No need to use i_size_read() here, the i_size
310          * cannot change under us because we hold the i_mutex.
311          */
312         if (last_pos > inode->i_size) {
313                 inode_add_bytes(inode, last_pos - inode->i_size);
314                 i_size_write(inode, last_pos);
315         }
316         set_page_dirty(page);
317 out:
318         unlock_page(page);
319         put_page(page);
320 
321         return copied;
322 }
323 
324 
325 const struct address_space_operations v9fs_addr_operations = {
326         .readpage = v9fs_vfs_readpage,
327         .readpages = v9fs_vfs_readpages,
328         .set_page_dirty = __set_page_dirty_nobuffers,
329         .writepage = v9fs_vfs_writepage,
330         .write_begin = v9fs_write_begin,
331         .write_end = v9fs_write_end,
332         .releasepage = v9fs_release_page,
333         .invalidatepage = v9fs_invalidate_page,
334         .launder_page = v9fs_launder_page,
335         .direct_IO = v9fs_direct_IO,
336 };
337 

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp