1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright (c) 2014 Christoph Hellwig.
4 */
5 #include "xfs.h"
6 #include "xfs_shared.h"
7 #include "xfs_format.h"
8 #include "xfs_log_format.h"
9 #include "xfs_trans_resv.h"
10 #include "xfs_mount.h"
11 #include "xfs_inode.h"
12 #include "xfs_trans.h"
13 #include "xfs_bmap.h"
14 #include "xfs_iomap.h"
15 #include "xfs_pnfs.h"
16
17 /*
18 * Ensure that we do not have any outstanding pNFS layouts that can be used by
19 * clients to directly read from or write to this inode. This must be called
20 * before every operation that can remove blocks from the extent map.
21 * Additionally we call it during the write operation, where aren't concerned
22 * about exposing unallocated blocks but just want to provide basic
23 * synchronization between a local writer and pNFS clients. mmap writes would
24 * also benefit from this sort of synchronization, but due to the tricky locking
25 * rules in the page fault path we don't bother.
26 */
27 int
xfs_break_leased_layouts(struct inode * inode,uint * iolock,bool * did_unlock)28 xfs_break_leased_layouts(
29 struct inode *inode,
30 uint *iolock,
31 bool *did_unlock)
32 {
33 struct xfs_inode *ip = XFS_I(inode);
34 int error;
35
36 while ((error = break_layout(inode, false)) == -EWOULDBLOCK) {
37 xfs_iunlock(ip, *iolock);
38 *did_unlock = true;
39 error = break_layout(inode, true);
40 *iolock &= ~XFS_IOLOCK_SHARED;
41 *iolock |= XFS_IOLOCK_EXCL;
42 xfs_ilock(ip, *iolock);
43 }
44
45 return error;
46 }
47
48 /*
49 * Get a unique ID including its location so that the client can identify
50 * the exported device.
51 */
52 int
xfs_fs_get_uuid(struct super_block * sb,u8 * buf,u32 * len,u64 * offset)53 xfs_fs_get_uuid(
54 struct super_block *sb,
55 u8 *buf,
56 u32 *len,
57 u64 *offset)
58 {
59 struct xfs_mount *mp = XFS_M(sb);
60
61 xfs_notice_once(mp,
62 "Using experimental pNFS feature, use at your own risk!");
63
64 if (*len < sizeof(uuid_t))
65 return -EINVAL;
66
67 memcpy(buf, &mp->m_sb.sb_uuid, sizeof(uuid_t));
68 *len = sizeof(uuid_t);
69 *offset = offsetof(struct xfs_dsb, sb_uuid);
70 return 0;
71 }
72
73 /*
74 * We cannot use file based VFS helpers such as file_modified() to update
75 * inode state as we modify the data/metadata in the inode here. Hence we have
76 * to open code the timestamp updates and SUID/SGID stripping. We also need
77 * to set the inode prealloc flag to ensure that the extents we allocate are not
78 * removed if the inode is reclaimed from memory before xfs_fs_block_commit()
79 * is from the client to indicate that data has been written and the file size
80 * can be extended.
81 */
82 static int
xfs_fs_map_update_inode(struct xfs_inode * ip)83 xfs_fs_map_update_inode(
84 struct xfs_inode *ip)
85 {
86 struct xfs_trans *tp;
87 int error;
88
89 error = xfs_trans_alloc(ip->i_mount, &M_RES(ip->i_mount)->tr_writeid,
90 0, 0, 0, &tp);
91 if (error)
92 return error;
93
94 xfs_ilock(ip, XFS_ILOCK_EXCL);
95 xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
96
97 VFS_I(ip)->i_mode &= ~S_ISUID;
98 if (VFS_I(ip)->i_mode & S_IXGRP)
99 VFS_I(ip)->i_mode &= ~S_ISGID;
100 xfs_trans_ichgtime(tp, ip, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
101 ip->i_diflags |= XFS_DIFLAG_PREALLOC;
102
103 xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
104 return xfs_trans_commit(tp);
105 }
106
107 /*
108 * Get a layout for the pNFS client.
109 */
110 int
xfs_fs_map_blocks(struct inode * inode,loff_t offset,u64 length,struct iomap * iomap,bool write,u32 * device_generation)111 xfs_fs_map_blocks(
112 struct inode *inode,
113 loff_t offset,
114 u64 length,
115 struct iomap *iomap,
116 bool write,
117 u32 *device_generation)
118 {
119 struct xfs_inode *ip = XFS_I(inode);
120 struct xfs_mount *mp = ip->i_mount;
121 struct xfs_bmbt_irec imap;
122 xfs_fileoff_t offset_fsb, end_fsb;
123 loff_t limit;
124 int bmapi_flags = XFS_BMAPI_ENTIRE;
125 int nimaps = 1;
126 uint lock_flags;
127 int error = 0;
128
129 if (xfs_is_shutdown(mp))
130 return -EIO;
131
132 /*
133 * We can't export inodes residing on the realtime device. The realtime
134 * device doesn't have a UUID to identify it, so the client has no way
135 * to find it.
136 */
137 if (XFS_IS_REALTIME_INODE(ip))
138 return -ENXIO;
139
140 /*
141 * The pNFS block layout spec actually supports reflink like
142 * functionality, but the Linux pNFS server doesn't implement it yet.
143 */
144 if (xfs_is_reflink_inode(ip))
145 return -ENXIO;
146
147 /*
148 * Lock out any other I/O before we flush and invalidate the pagecache,
149 * and then hand out a layout to the remote system. This is very
150 * similar to direct I/O, except that the synchronization is much more
151 * complicated. See the comment near xfs_break_leased_layouts
152 * for a detailed explanation.
153 */
154 xfs_ilock(ip, XFS_IOLOCK_EXCL);
155
156 error = -EINVAL;
157 limit = mp->m_super->s_maxbytes;
158 if (!write)
159 limit = max(limit, round_up(i_size_read(inode),
160 inode->i_sb->s_blocksize));
161 if (offset > limit)
162 goto out_unlock;
163 if (offset > limit - length)
164 length = limit - offset;
165
166 error = filemap_write_and_wait(inode->i_mapping);
167 if (error)
168 goto out_unlock;
169 error = invalidate_inode_pages2(inode->i_mapping);
170 if (WARN_ON_ONCE(error))
171 goto out_unlock;
172
173 end_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)offset + length);
174 offset_fsb = XFS_B_TO_FSBT(mp, offset);
175
176 lock_flags = xfs_ilock_data_map_shared(ip);
177 error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb,
178 &imap, &nimaps, bmapi_flags);
179
180 ASSERT(!nimaps || imap.br_startblock != DELAYSTARTBLOCK);
181
182 if (!error && write &&
183 (!nimaps || imap.br_startblock == HOLESTARTBLOCK)) {
184 if (offset + length > XFS_ISIZE(ip))
185 end_fsb = xfs_iomap_eof_align_last_fsb(ip, end_fsb);
186 else if (nimaps && imap.br_startblock == HOLESTARTBLOCK)
187 end_fsb = min(end_fsb, imap.br_startoff +
188 imap.br_blockcount);
189 xfs_iunlock(ip, lock_flags);
190
191 error = xfs_iomap_write_direct(ip, offset_fsb,
192 end_fsb - offset_fsb, 0, &imap);
193 if (error)
194 goto out_unlock;
195
196 /*
197 * Ensure the next transaction is committed synchronously so
198 * that the blocks allocated and handed out to the client are
199 * guaranteed to be present even after a server crash.
200 */
201 error = xfs_fs_map_update_inode(ip);
202 if (!error)
203 error = xfs_log_force_inode(ip);
204 if (error)
205 goto out_unlock;
206
207 } else {
208 xfs_iunlock(ip, lock_flags);
209 }
210 xfs_iunlock(ip, XFS_IOLOCK_EXCL);
211
212 error = xfs_bmbt_to_iomap(ip, iomap, &imap, 0, 0);
213 *device_generation = mp->m_generation;
214 return error;
215 out_unlock:
216 xfs_iunlock(ip, XFS_IOLOCK_EXCL);
217 return error;
218 }
219
220 /*
221 * Ensure the size update falls into a valid allocated block.
222 */
223 static int
xfs_pnfs_validate_isize(struct xfs_inode * ip,xfs_off_t isize)224 xfs_pnfs_validate_isize(
225 struct xfs_inode *ip,
226 xfs_off_t isize)
227 {
228 struct xfs_bmbt_irec imap;
229 int nimaps = 1;
230 int error = 0;
231
232 xfs_ilock(ip, XFS_ILOCK_SHARED);
233 error = xfs_bmapi_read(ip, XFS_B_TO_FSBT(ip->i_mount, isize - 1), 1,
234 &imap, &nimaps, 0);
235 xfs_iunlock(ip, XFS_ILOCK_SHARED);
236 if (error)
237 return error;
238
239 if (imap.br_startblock == HOLESTARTBLOCK ||
240 imap.br_startblock == DELAYSTARTBLOCK ||
241 imap.br_state == XFS_EXT_UNWRITTEN)
242 return -EIO;
243 return 0;
244 }
245
246 /*
247 * Make sure the blocks described by maps are stable on disk. This includes
248 * converting any unwritten extents, flushing the disk cache and updating the
249 * time stamps.
250 *
251 * Note that we rely on the caller to always send us a timestamp update so that
252 * we always commit a transaction here. If that stops being true we will have
253 * to manually flush the cache here similar to what the fsync code path does
254 * for datasyncs on files that have no dirty metadata.
255 */
256 int
xfs_fs_commit_blocks(struct inode * inode,struct iomap * maps,int nr_maps,struct iattr * iattr)257 xfs_fs_commit_blocks(
258 struct inode *inode,
259 struct iomap *maps,
260 int nr_maps,
261 struct iattr *iattr)
262 {
263 struct xfs_inode *ip = XFS_I(inode);
264 struct xfs_mount *mp = ip->i_mount;
265 struct xfs_trans *tp;
266 bool update_isize = false;
267 int error, i;
268 loff_t size;
269
270 ASSERT(iattr->ia_valid & (ATTR_ATIME|ATTR_CTIME|ATTR_MTIME));
271
272 xfs_ilock(ip, XFS_IOLOCK_EXCL);
273
274 size = i_size_read(inode);
275 if ((iattr->ia_valid & ATTR_SIZE) && iattr->ia_size > size) {
276 update_isize = true;
277 size = iattr->ia_size;
278 }
279
280 for (i = 0; i < nr_maps; i++) {
281 u64 start, length, end;
282
283 start = maps[i].offset;
284 if (start > size)
285 continue;
286
287 end = start + maps[i].length;
288 if (end > size)
289 end = size;
290
291 length = end - start;
292 if (!length)
293 continue;
294
295 /*
296 * Make sure reads through the pagecache see the new data.
297 */
298 error = invalidate_inode_pages2_range(inode->i_mapping,
299 start >> PAGE_SHIFT,
300 (end - 1) >> PAGE_SHIFT);
301 WARN_ON_ONCE(error);
302
303 error = xfs_iomap_write_unwritten(ip, start, length, false);
304 if (error)
305 goto out_drop_iolock;
306 }
307
308 if (update_isize) {
309 error = xfs_pnfs_validate_isize(ip, size);
310 if (error)
311 goto out_drop_iolock;
312 }
313
314 error = xfs_trans_alloc(mp, &M_RES(mp)->tr_ichange, 0, 0, 0, &tp);
315 if (error)
316 goto out_drop_iolock;
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 ASSERT(!(iattr->ia_valid & (ATTR_UID | ATTR_GID)));
323 setattr_copy(&init_user_ns, inode, iattr);
324 if (update_isize) {
325 i_size_write(inode, iattr->ia_size);
326 ip->i_disk_size = iattr->ia_size;
327 }
328
329 xfs_trans_set_sync(tp);
330 error = xfs_trans_commit(tp);
331
332 out_drop_iolock:
333 xfs_iunlock(ip, XFS_IOLOCK_EXCL);
334 return error;
335 }
336
