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f79e2abb AM |
1 | /* |
2 | * High-level sync()-related operations | |
3 | */ | |
4 | ||
5 | #include <linux/kernel.h> | |
6 | #include <linux/file.h> | |
7 | #include <linux/fs.h> | |
8 | #include <linux/module.h> | |
9 | #include <linux/writeback.h> | |
10 | #include <linux/syscalls.h> | |
11 | #include <linux/linkage.h> | |
12 | #include <linux/pagemap.h> | |
cf9a2ae8 DH |
13 | #include <linux/quotaops.h> |
14 | #include <linux/buffer_head.h> | |
f79e2abb AM |
15 | |
16 | #define VALID_FLAGS (SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE| \ | |
17 | SYNC_FILE_RANGE_WAIT_AFTER) | |
18 | ||
cf9a2ae8 DH |
19 | /* |
20 | * sync everything. Start out by waking pdflush, because that writes back | |
21 | * all queues in parallel. | |
22 | */ | |
23 | static void do_sync(unsigned long wait) | |
24 | { | |
25 | wakeup_pdflush(0); | |
26 | sync_inodes(0); /* All mappings, inodes and their blockdevs */ | |
27 | DQUOT_SYNC(NULL); | |
28 | sync_supers(); /* Write the superblocks */ | |
29 | sync_filesystems(0); /* Start syncing the filesystems */ | |
30 | sync_filesystems(wait); /* Waitingly sync the filesystems */ | |
31 | sync_inodes(wait); /* Mappings, inodes and blockdevs, again. */ | |
32 | if (!wait) | |
33 | printk("Emergency Sync complete\n"); | |
34 | if (unlikely(laptop_mode)) | |
35 | laptop_sync_completion(); | |
36 | } | |
37 | ||
38 | asmlinkage long sys_sync(void) | |
39 | { | |
40 | do_sync(1); | |
41 | return 0; | |
42 | } | |
43 | ||
44 | void emergency_sync(void) | |
45 | { | |
46 | pdflush_operation(do_sync, 0); | |
47 | } | |
48 | ||
49 | /* | |
50 | * Generic function to fsync a file. | |
51 | * | |
52 | * filp may be NULL if called via the msync of a vma. | |
53 | */ | |
54 | int file_fsync(struct file *filp, struct dentry *dentry, int datasync) | |
55 | { | |
56 | struct inode * inode = dentry->d_inode; | |
57 | struct super_block * sb; | |
58 | int ret, err; | |
59 | ||
60 | /* sync the inode to buffers */ | |
61 | ret = write_inode_now(inode, 0); | |
62 | ||
63 | /* sync the superblock to buffers */ | |
64 | sb = inode->i_sb; | |
65 | lock_super(sb); | |
66 | if (sb->s_op->write_super) | |
67 | sb->s_op->write_super(sb); | |
68 | unlock_super(sb); | |
69 | ||
70 | /* .. finally sync the buffers to disk */ | |
71 | err = sync_blockdev(sb->s_bdev); | |
72 | if (!ret) | |
73 | ret = err; | |
74 | return ret; | |
75 | } | |
76 | ||
77 | long do_fsync(struct file *file, int datasync) | |
78 | { | |
79 | int ret; | |
80 | int err; | |
81 | struct address_space *mapping = file->f_mapping; | |
82 | ||
83 | if (!file->f_op || !file->f_op->fsync) { | |
84 | /* Why? We can still call filemap_fdatawrite */ | |
85 | ret = -EINVAL; | |
86 | goto out; | |
87 | } | |
88 | ||
89 | ret = filemap_fdatawrite(mapping); | |
90 | ||
91 | /* | |
92 | * We need to protect against concurrent writers, which could cause | |
93 | * livelocks in fsync_buffers_list(). | |
94 | */ | |
95 | mutex_lock(&mapping->host->i_mutex); | |
96 | err = file->f_op->fsync(file, file->f_dentry, datasync); | |
97 | if (!ret) | |
98 | ret = err; | |
99 | mutex_unlock(&mapping->host->i_mutex); | |
100 | err = filemap_fdatawait(mapping); | |
101 | if (!ret) | |
102 | ret = err; | |
103 | out: | |
104 | return ret; | |
105 | } | |
106 | ||
107 | static long __do_fsync(unsigned int fd, int datasync) | |
108 | { | |
109 | struct file *file; | |
110 | int ret = -EBADF; | |
111 | ||
112 | file = fget(fd); | |
113 | if (file) { | |
114 | ret = do_fsync(file, datasync); | |
115 | fput(file); | |
116 | } | |
117 | return ret; | |
118 | } | |
119 | ||
120 | asmlinkage long sys_fsync(unsigned int fd) | |
121 | { | |
122 | return __do_fsync(fd, 0); | |
123 | } | |
124 | ||
125 | asmlinkage long sys_fdatasync(unsigned int fd) | |
126 | { | |
127 | return __do_fsync(fd, 1); | |
128 | } | |
129 | ||
f79e2abb AM |
130 | /* |
131 | * sys_sync_file_range() permits finely controlled syncing over a segment of | |
132 | * a file in the range offset .. (offset+nbytes-1) inclusive. If nbytes is | |
133 | * zero then sys_sync_file_range() will operate from offset out to EOF. | |
134 | * | |
135 | * The flag bits are: | |
136 | * | |
137 | * SYNC_FILE_RANGE_WAIT_BEFORE: wait upon writeout of all pages in the range | |
138 | * before performing the write. | |
139 | * | |
140 | * SYNC_FILE_RANGE_WRITE: initiate writeout of all those dirty pages in the | |
141 | * range which are not presently under writeback. | |
142 | * | |
143 | * SYNC_FILE_RANGE_WAIT_AFTER: wait upon writeout of all pages in the range | |
144 | * after performing the write. | |
145 | * | |
146 | * Useful combinations of the flag bits are: | |
147 | * | |
148 | * SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE: ensures that all pages | |
149 | * in the range which were dirty on entry to sys_sync_file_range() are placed | |
150 | * under writeout. This is a start-write-for-data-integrity operation. | |
151 | * | |
152 | * SYNC_FILE_RANGE_WRITE: start writeout of all dirty pages in the range which | |
153 | * are not presently under writeout. This is an asynchronous flush-to-disk | |
154 | * operation. Not suitable for data integrity operations. | |
155 | * | |
156 | * SYNC_FILE_RANGE_WAIT_BEFORE (or SYNC_FILE_RANGE_WAIT_AFTER): wait for | |
157 | * completion of writeout of all pages in the range. This will be used after an | |
158 | * earlier SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE operation to wait | |
159 | * for that operation to complete and to return the result. | |
160 | * | |
161 | * SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE|SYNC_FILE_RANGE_WAIT_AFTER: | |
162 | * a traditional sync() operation. This is a write-for-data-integrity operation | |
163 | * which will ensure that all pages in the range which were dirty on entry to | |
164 | * sys_sync_file_range() are committed to disk. | |
165 | * | |
166 | * | |
167 | * SYNC_FILE_RANGE_WAIT_BEFORE and SYNC_FILE_RANGE_WAIT_AFTER will detect any | |
168 | * I/O errors or ENOSPC conditions and will return those to the caller, after | |
169 | * clearing the EIO and ENOSPC flags in the address_space. | |
170 | * | |
171 | * It should be noted that none of these operations write out the file's | |
172 | * metadata. So unless the application is strictly performing overwrites of | |
173 | * already-instantiated disk blocks, there are no guarantees here that the data | |
174 | * will be available after a crash. | |
175 | */ | |
176 | asmlinkage long sys_sync_file_range(int fd, loff_t offset, loff_t nbytes, | |
5246d050 | 177 | unsigned int flags) |
f79e2abb AM |
178 | { |
179 | int ret; | |
180 | struct file *file; | |
181 | loff_t endbyte; /* inclusive */ | |
182 | int fput_needed; | |
183 | umode_t i_mode; | |
184 | ||
185 | ret = -EINVAL; | |
186 | if (flags & ~VALID_FLAGS) | |
187 | goto out; | |
188 | ||
189 | endbyte = offset + nbytes; | |
190 | ||
191 | if ((s64)offset < 0) | |
192 | goto out; | |
193 | if ((s64)endbyte < 0) | |
194 | goto out; | |
195 | if (endbyte < offset) | |
196 | goto out; | |
197 | ||
198 | if (sizeof(pgoff_t) == 4) { | |
199 | if (offset >= (0x100000000ULL << PAGE_CACHE_SHIFT)) { | |
200 | /* | |
201 | * The range starts outside a 32 bit machine's | |
202 | * pagecache addressing capabilities. Let it "succeed" | |
203 | */ | |
204 | ret = 0; | |
205 | goto out; | |
206 | } | |
207 | if (endbyte >= (0x100000000ULL << PAGE_CACHE_SHIFT)) { | |
208 | /* | |
209 | * Out to EOF | |
210 | */ | |
211 | nbytes = 0; | |
212 | } | |
213 | } | |
214 | ||
215 | if (nbytes == 0) | |
111ebb6e | 216 | endbyte = LLONG_MAX; |
f79e2abb AM |
217 | else |
218 | endbyte--; /* inclusive */ | |
219 | ||
220 | ret = -EBADF; | |
221 | file = fget_light(fd, &fput_needed); | |
222 | if (!file) | |
223 | goto out; | |
224 | ||
225 | i_mode = file->f_dentry->d_inode->i_mode; | |
226 | ret = -ESPIPE; | |
227 | if (!S_ISREG(i_mode) && !S_ISBLK(i_mode) && !S_ISDIR(i_mode) && | |
228 | !S_ISLNK(i_mode)) | |
229 | goto out_put; | |
230 | ||
231 | ret = do_sync_file_range(file, offset, endbyte, flags); | |
232 | out_put: | |
233 | fput_light(file, fput_needed); | |
234 | out: | |
235 | return ret; | |
236 | } | |
237 | ||
238 | /* | |
239 | * `endbyte' is inclusive | |
240 | */ | |
241 | int do_sync_file_range(struct file *file, loff_t offset, loff_t endbyte, | |
5246d050 | 242 | unsigned int flags) |
f79e2abb AM |
243 | { |
244 | int ret; | |
245 | struct address_space *mapping; | |
246 | ||
247 | mapping = file->f_mapping; | |
248 | if (!mapping) { | |
249 | ret = -EINVAL; | |
250 | goto out; | |
251 | } | |
252 | ||
253 | ret = 0; | |
254 | if (flags & SYNC_FILE_RANGE_WAIT_BEFORE) { | |
255 | ret = wait_on_page_writeback_range(mapping, | |
256 | offset >> PAGE_CACHE_SHIFT, | |
257 | endbyte >> PAGE_CACHE_SHIFT); | |
258 | if (ret < 0) | |
259 | goto out; | |
260 | } | |
261 | ||
262 | if (flags & SYNC_FILE_RANGE_WRITE) { | |
263 | ret = __filemap_fdatawrite_range(mapping, offset, endbyte, | |
264 | WB_SYNC_NONE); | |
265 | if (ret < 0) | |
266 | goto out; | |
267 | } | |
268 | ||
269 | if (flags & SYNC_FILE_RANGE_WAIT_AFTER) { | |
270 | ret = wait_on_page_writeback_range(mapping, | |
271 | offset >> PAGE_CACHE_SHIFT, | |
272 | endbyte >> PAGE_CACHE_SHIFT); | |
273 | } | |
274 | out: | |
275 | return ret; | |
276 | } | |
277 | EXPORT_SYMBOL_GPL(do_sync_file_range); |