1 /*
2 * Copyright (c) 2014 Christoph Hellwig.
3 */
4 #include "xfs.h"
5 #include "xfs_format.h"
6 #include "xfs_log_format.h"
7 #include "xfs_trans_resv.h"
8 #include "xfs_sb.h"
9 #include "xfs_mount.h"
10 #include "xfs_inode.h"
11 #include "xfs_trans.h"
12 #include "xfs_log.h"
13 #include "xfs_bmap.h"
14 #include "xfs_bmap_util.h"
15 #include "xfs_error.h"
16 #include "xfs_iomap.h"
17 #include "xfs_shared.h"
18 #include "xfs_bit.h"
19 #include "xfs_pnfs.h"
20
21 /*
22 * Ensure that we do not have any outstanding pNFS layouts that can be used by
23 * clients to directly read from or write to this inode. This must be called
24 * before every operation that can remove blocks from the extent map.
25 * Additionally we call it during the write operation, where aren't concerned
26 * about exposing unallocated blocks but just want to provide basic
27 * synchronization between a local writer and pNFS clients. mmap writes would
28 * also benefit from this sort of synchronization, but due to the tricky locking
29 * rules in the page fault path we don't bother.
30 */
31 int
xfs_break_layouts(struct inode * inode,uint * iolock,bool with_imutex)32 xfs_break_layouts(
33 struct inode *inode,
34 uint *iolock,
35 bool with_imutex)
36 {
37 struct xfs_inode *ip = XFS_I(inode);
38 int error;
39
40 ASSERT(xfs_isilocked(ip, XFS_IOLOCK_SHARED|XFS_IOLOCK_EXCL));
41
42 while ((error = break_layout(inode, false) == -EWOULDBLOCK)) {
43 xfs_iunlock(ip, *iolock);
44 if (with_imutex && (*iolock & XFS_IOLOCK_EXCL))
45 mutex_unlock(&inode->i_mutex);
46 error = break_layout(inode, true);
47 *iolock = XFS_IOLOCK_EXCL;
48 if (with_imutex)
49 mutex_lock(&inode->i_mutex);
50 xfs_ilock(ip, *iolock);
51 }
52
53 return error;
54 }
55
56 /*
57 * Get a unique ID including its location so that the client can identify
58 * the exported device.
59 */
60 int
xfs_fs_get_uuid(struct super_block * sb,u8 * buf,u32 * len,u64 * offset)61 xfs_fs_get_uuid(
62 struct super_block *sb,
63 u8 *buf,
64 u32 *len,
65 u64 *offset)
66 {
67 struct xfs_mount *mp = XFS_M(sb);
68
69 printk_once(KERN_NOTICE
70 "XFS (%s): using experimental pNFS feature, use at your own risk!\n",
71 mp->m_fsname);
72
73 if (*len < sizeof(uuid_t))
74 return -EINVAL;
75
76 memcpy(buf, &mp->m_sb.sb_uuid, sizeof(uuid_t));
77 *len = sizeof(uuid_t);
78 *offset = offsetof(struct xfs_dsb, sb_uuid);
79 return 0;
80 }
81
82 static void
xfs_bmbt_to_iomap(struct xfs_inode * ip,struct iomap * iomap,struct xfs_bmbt_irec * imap)83 xfs_bmbt_to_iomap(
84 struct xfs_inode *ip,
85 struct iomap *iomap,
86 struct xfs_bmbt_irec *imap)
87 {
88 struct xfs_mount *mp = ip->i_mount;
89
90 if (imap->br_startblock == HOLESTARTBLOCK) {
91 iomap->blkno = IOMAP_NULL_BLOCK;
92 iomap->type = IOMAP_HOLE;
93 } else if (imap->br_startblock == DELAYSTARTBLOCK) {
94 iomap->blkno = IOMAP_NULL_BLOCK;
95 iomap->type = IOMAP_DELALLOC;
96 } else {
97 iomap->blkno =
98 XFS_FSB_TO_DADDR(ip->i_mount, imap->br_startblock);
99 if (imap->br_state == XFS_EXT_UNWRITTEN)
100 iomap->type = IOMAP_UNWRITTEN;
101 else
102 iomap->type = IOMAP_MAPPED;
103 }
104 iomap->offset = XFS_FSB_TO_B(mp, imap->br_startoff);
105 iomap->length = XFS_FSB_TO_B(mp, imap->br_blockcount);
106 }
107
108 /*
109 * Get a layout for the pNFS client.
110 */
111 int
xfs_fs_map_blocks(struct inode * inode,loff_t offset,u64 length,struct iomap * iomap,bool write,u32 * device_generation)112 xfs_fs_map_blocks(
113 struct inode *inode,
114 loff_t offset,
115 u64 length,
116 struct iomap *iomap,
117 bool write,
118 u32 *device_generation)
119 {
120 struct xfs_inode *ip = XFS_I(inode);
121 struct xfs_mount *mp = ip->i_mount;
122 struct xfs_bmbt_irec imap;
123 xfs_fileoff_t offset_fsb, end_fsb;
124 loff_t limit;
125 int bmapi_flags = XFS_BMAPI_ENTIRE;
126 int nimaps = 1;
127 uint lock_flags;
128 int error = 0;
129
130 if (XFS_FORCED_SHUTDOWN(mp))
131 return -EIO;
132
133 /*
134 * We can't export inodes residing on the realtime device. The realtime
135 * device doesn't have a UUID to identify it, so the client has no way
136 * to find it.
137 */
138 if (XFS_IS_REALTIME_INODE(ip))
139 return -ENXIO;
140
141 /*
142 * Lock out any other I/O before we flush and invalidate the pagecache,
143 * and then hand out a layout to the remote system. This is very
144 * similar to direct I/O, except that the synchronization is much more
145 * complicated. See the comment near xfs_break_layouts for a detailed
146 * explanation.
147 */
148 xfs_ilock(ip, XFS_IOLOCK_EXCL);
149
150 error = -EINVAL;
151 limit = mp->m_super->s_maxbytes;
152 if (!write)
153 limit = max(limit, round_up(i_size_read(inode),
154 inode->i_sb->s_blocksize));
155 if (offset > limit)
156 goto out_unlock;
157 if (offset > limit - length)
158 length = limit - offset;
159
160 error = filemap_write_and_wait(inode->i_mapping);
161 if (error)
162 goto out_unlock;
163 error = invalidate_inode_pages2(inode->i_mapping);
164 if (WARN_ON_ONCE(error))
165 goto out_unlock;
166
167 end_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)offset + length);
168 offset_fsb = XFS_B_TO_FSBT(mp, offset);
169
170 lock_flags = xfs_ilock_data_map_shared(ip);
171 error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb,
172 &imap, &nimaps, bmapi_flags);
173 xfs_iunlock(ip, lock_flags);
174
175 if (error)
176 goto out_unlock;
177
178 if (write) {
179 enum xfs_prealloc_flags flags = 0;
180
181 ASSERT(imap.br_startblock != DELAYSTARTBLOCK);
182
183 if (!nimaps || imap.br_startblock == HOLESTARTBLOCK) {
184 /*
185 * xfs_iomap_write_direct() expects to take ownership of
186 * the shared ilock.
187 */
188 xfs_ilock(ip, XFS_ILOCK_SHARED);
189 error = xfs_iomap_write_direct(ip, offset, length,
190 &imap, nimaps);
191 if (error)
192 goto out_unlock;
193
194 /*
195 * Ensure the next transaction is committed
196 * synchronously so that the blocks allocated and
197 * handed out to the client are guaranteed to be
198 * present even after a server crash.
199 */
200 flags |= XFS_PREALLOC_SET | XFS_PREALLOC_SYNC;
201 }
202
203 error = xfs_update_prealloc_flags(ip, flags);
204 if (error)
205 goto out_unlock;
206 }
207 xfs_iunlock(ip, XFS_IOLOCK_EXCL);
208
209 xfs_bmbt_to_iomap(ip, iomap, &imap);
210 *device_generation = mp->m_generation;
211 return error;
212 out_unlock:
213 xfs_iunlock(ip, XFS_IOLOCK_EXCL);
214 return error;
215 }
216
217 /*
218 * Ensure the size update falls into a valid allocated block.
219 */
220 static int
xfs_pnfs_validate_isize(struct xfs_inode * ip,xfs_off_t isize)221 xfs_pnfs_validate_isize(
222 struct xfs_inode *ip,
223 xfs_off_t isize)
224 {
225 struct xfs_bmbt_irec imap;
226 int nimaps = 1;
227 int error = 0;
228
229 xfs_ilock(ip, XFS_ILOCK_SHARED);
230 error = xfs_bmapi_read(ip, XFS_B_TO_FSBT(ip->i_mount, isize - 1), 1,
231 &imap, &nimaps, 0);
232 xfs_iunlock(ip, XFS_ILOCK_SHARED);
233 if (error)
234 return error;
235
236 if (imap.br_startblock == HOLESTARTBLOCK ||
237 imap.br_startblock == DELAYSTARTBLOCK ||
238 imap.br_state == XFS_EXT_UNWRITTEN)
239 return -EIO;
240 return 0;
241 }
242
243 /*
244 * Make sure the blocks described by maps are stable on disk. This includes
245 * converting any unwritten extents, flushing the disk cache and updating the
246 * time stamps.
247 *
248 * Note that we rely on the caller to always send us a timestamp update so that
249 * we always commit a transaction here. If that stops being true we will have
250 * to manually flush the cache here similar to what the fsync code path does
251 * for datasyncs on files that have no dirty metadata.
252 */
253 int
xfs_fs_commit_blocks(struct inode * inode,struct iomap * maps,int nr_maps,struct iattr * iattr)254 xfs_fs_commit_blocks(
255 struct inode *inode,
256 struct iomap *maps,
257 int nr_maps,
258 struct iattr *iattr)
259 {
260 struct xfs_inode *ip = XFS_I(inode);
261 struct xfs_mount *mp = ip->i_mount;
262 struct xfs_trans *tp;
263 bool update_isize = false;
264 int error, i;
265 loff_t size;
266
267 ASSERT(iattr->ia_valid & (ATTR_ATIME|ATTR_CTIME|ATTR_MTIME));
268
269 xfs_ilock(ip, XFS_IOLOCK_EXCL);
270
271 size = i_size_read(inode);
272 if ((iattr->ia_valid & ATTR_SIZE) && iattr->ia_size > size) {
273 update_isize = true;
274 size = iattr->ia_size;
275 }
276
277 for (i = 0; i < nr_maps; i++) {
278 u64 start, length, end;
279
280 start = maps[i].offset;
281 if (start > size)
282 continue;
283
284 end = start + maps[i].length;
285 if (end > size)
286 end = size;
287
288 length = end - start;
289 if (!length)
290 continue;
291
292 /*
293 * Make sure reads through the pagecache see the new data.
294 */
295 error = invalidate_inode_pages2_range(inode->i_mapping,
296 start >> PAGE_CACHE_SHIFT,
297 (end - 1) >> PAGE_CACHE_SHIFT);
298 WARN_ON_ONCE(error);
299
300 error = xfs_iomap_write_unwritten(ip, start, length);
301 if (error)
302 goto out_drop_iolock;
303 }
304
305 if (update_isize) {
306 error = xfs_pnfs_validate_isize(ip, size);
307 if (error)
308 goto out_drop_iolock;
309 }
310
311 tp = xfs_trans_alloc(mp, XFS_TRANS_SETATTR_NOT_SIZE);
312 error = xfs_trans_reserve(tp, &M_RES(mp)->tr_ichange, 0, 0);
313 if (error) {
314 xfs_trans_cancel(tp);
315 goto out_drop_iolock;
316 }
317
318 xfs_ilock(ip, XFS_ILOCK_EXCL);
319 xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
320 xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
321
322 xfs_setattr_time(ip, iattr);
323 if (update_isize) {
324 i_size_write(inode, iattr->ia_size);
325 ip->i_d.di_size = iattr->ia_size;
326 }
327
328 xfs_trans_set_sync(tp);
329 error = xfs_trans_commit(tp);
330
331 out_drop_iolock:
332 xfs_iunlock(ip, XFS_IOLOCK_EXCL);
333 return error;
334 }
335