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