Commit | Line | Data |
---|---|---|
8f09e987 BC |
1 | /* |
2 | * OMFS (as used by RIO Karma) file operations. | |
3 | * Copyright (C) 2005 Bob Copeland <me@bobcopeland.com> | |
4 | * Released under GPL v2. | |
5 | */ | |
6 | ||
7 | #include <linux/version.h> | |
8 | #include <linux/module.h> | |
9 | #include <linux/fs.h> | |
10 | #include <linux/buffer_head.h> | |
11 | #include <linux/mpage.h> | |
12 | #include "omfs.h" | |
13 | ||
14 | static int omfs_sync_file(struct file *file, struct dentry *dentry, | |
15 | int datasync) | |
16 | { | |
17 | struct inode *inode = dentry->d_inode; | |
18 | int err; | |
19 | ||
20 | err = sync_mapping_buffers(inode->i_mapping); | |
21 | if (!(inode->i_state & I_DIRTY)) | |
22 | return err; | |
23 | if (datasync && !(inode->i_state & I_DIRTY_DATASYNC)) | |
24 | return err; | |
25 | err |= omfs_sync_inode(inode); | |
26 | return err ? -EIO : 0; | |
27 | } | |
28 | ||
9419fc1c BC |
29 | static u32 omfs_max_extents(struct omfs_sb_info *sbi, int offset) |
30 | { | |
31 | return (sbi->s_sys_blocksize - offset - | |
32 | sizeof(struct omfs_extent)) / | |
33 | sizeof(struct omfs_extent_entry) + 1; | |
34 | } | |
35 | ||
8f09e987 BC |
36 | void omfs_make_empty_table(struct buffer_head *bh, int offset) |
37 | { | |
38 | struct omfs_extent *oe = (struct omfs_extent *) &bh->b_data[offset]; | |
39 | ||
d406f66d | 40 | oe->e_next = ~cpu_to_be64(0ULL); |
8f09e987 BC |
41 | oe->e_extent_count = cpu_to_be32(1), |
42 | oe->e_fill = cpu_to_be32(0x22), | |
d406f66d HH |
43 | oe->e_entry.e_cluster = ~cpu_to_be64(0ULL); |
44 | oe->e_entry.e_blocks = ~cpu_to_be64(0ULL); | |
8f09e987 BC |
45 | } |
46 | ||
47 | int omfs_shrink_inode(struct inode *inode) | |
48 | { | |
49 | struct omfs_sb_info *sbi = OMFS_SB(inode->i_sb); | |
50 | struct omfs_extent *oe; | |
51 | struct omfs_extent_entry *entry; | |
52 | struct buffer_head *bh; | |
53 | u64 next, last; | |
54 | u32 extent_count; | |
9419fc1c | 55 | u32 max_extents; |
8f09e987 BC |
56 | int ret; |
57 | ||
58 | /* traverse extent table, freeing each entry that is greater | |
59 | * than inode->i_size; | |
60 | */ | |
61 | next = inode->i_ino; | |
62 | ||
63 | /* only support truncate -> 0 for now */ | |
64 | ret = -EIO; | |
65 | if (inode->i_size != 0) | |
66 | goto out; | |
67 | ||
68 | bh = sb_bread(inode->i_sb, clus_to_blk(sbi, next)); | |
69 | if (!bh) | |
70 | goto out; | |
71 | ||
72 | oe = (struct omfs_extent *)(&bh->b_data[OMFS_EXTENT_START]); | |
9419fc1c | 73 | max_extents = omfs_max_extents(sbi, OMFS_EXTENT_START); |
8f09e987 BC |
74 | |
75 | for (;;) { | |
76 | ||
9419fc1c BC |
77 | if (omfs_is_bad(sbi, (struct omfs_header *) bh->b_data, next)) |
78 | goto out_brelse; | |
8f09e987 BC |
79 | |
80 | extent_count = be32_to_cpu(oe->e_extent_count); | |
9419fc1c BC |
81 | |
82 | if (extent_count > max_extents) | |
83 | goto out_brelse; | |
84 | ||
8f09e987 BC |
85 | last = next; |
86 | next = be64_to_cpu(oe->e_next); | |
87 | entry = &oe->e_entry; | |
88 | ||
89 | /* ignore last entry as it is the terminator */ | |
90 | for (; extent_count > 1; extent_count--) { | |
91 | u64 start, count; | |
92 | start = be64_to_cpu(entry->e_cluster); | |
93 | count = be64_to_cpu(entry->e_blocks); | |
94 | ||
95 | omfs_clear_range(inode->i_sb, start, (int) count); | |
96 | entry++; | |
97 | } | |
98 | omfs_make_empty_table(bh, (char *) oe - bh->b_data); | |
99 | mark_buffer_dirty(bh); | |
100 | brelse(bh); | |
101 | ||
102 | if (last != inode->i_ino) | |
103 | omfs_clear_range(inode->i_sb, last, sbi->s_mirrors); | |
104 | ||
105 | if (next == ~0) | |
106 | break; | |
107 | ||
108 | bh = sb_bread(inode->i_sb, clus_to_blk(sbi, next)); | |
109 | if (!bh) | |
110 | goto out; | |
111 | oe = (struct omfs_extent *) (&bh->b_data[OMFS_EXTENT_CONT]); | |
9419fc1c | 112 | max_extents = omfs_max_extents(sbi, OMFS_EXTENT_CONT); |
8f09e987 BC |
113 | } |
114 | ret = 0; | |
115 | out: | |
116 | return ret; | |
9419fc1c BC |
117 | out_brelse: |
118 | brelse(bh); | |
119 | return ret; | |
8f09e987 BC |
120 | } |
121 | ||
122 | static void omfs_truncate(struct inode *inode) | |
123 | { | |
124 | omfs_shrink_inode(inode); | |
125 | mark_inode_dirty(inode); | |
126 | } | |
127 | ||
128 | /* | |
129 | * Add new blocks to the current extent, or create new entries/continuations | |
130 | * as necessary. | |
131 | */ | |
132 | static int omfs_grow_extent(struct inode *inode, struct omfs_extent *oe, | |
133 | u64 *ret_block) | |
134 | { | |
135 | struct omfs_extent_entry *terminator; | |
136 | struct omfs_extent_entry *entry = &oe->e_entry; | |
137 | struct omfs_sb_info *sbi = OMFS_SB(inode->i_sb); | |
138 | u32 extent_count = be32_to_cpu(oe->e_extent_count); | |
139 | u64 new_block = 0; | |
140 | u32 max_count; | |
141 | int new_count; | |
142 | int ret = 0; | |
143 | ||
144 | /* reached the end of the extent table with no blocks mapped. | |
145 | * there are three possibilities for adding: grow last extent, | |
146 | * add a new extent to the current extent table, and add a | |
147 | * continuation inode. in last two cases need an allocator for | |
148 | * sbi->s_cluster_size | |
149 | */ | |
150 | ||
151 | /* TODO: handle holes */ | |
152 | ||
153 | /* should always have a terminator */ | |
154 | if (extent_count < 1) | |
155 | return -EIO; | |
156 | ||
157 | /* trivially grow current extent, if next block is not taken */ | |
158 | terminator = entry + extent_count - 1; | |
159 | if (extent_count > 1) { | |
160 | entry = terminator-1; | |
161 | new_block = be64_to_cpu(entry->e_cluster) + | |
162 | be64_to_cpu(entry->e_blocks); | |
163 | ||
164 | if (omfs_allocate_block(inode->i_sb, new_block)) { | |
165 | entry->e_blocks = | |
166 | cpu_to_be64(be64_to_cpu(entry->e_blocks) + 1); | |
167 | terminator->e_blocks = ~(cpu_to_be64( | |
168 | be64_to_cpu(~terminator->e_blocks) + 1)); | |
169 | goto out; | |
170 | } | |
171 | } | |
9419fc1c | 172 | max_count = omfs_max_extents(sbi, OMFS_EXTENT_START); |
8f09e987 BC |
173 | |
174 | /* TODO: add a continuation block here */ | |
175 | if (be32_to_cpu(oe->e_extent_count) > max_count-1) | |
176 | return -EIO; | |
177 | ||
178 | /* try to allocate a new cluster */ | |
179 | ret = omfs_allocate_range(inode->i_sb, 1, sbi->s_clustersize, | |
180 | &new_block, &new_count); | |
181 | if (ret) | |
182 | goto out_fail; | |
183 | ||
184 | /* copy terminator down an entry */ | |
185 | entry = terminator; | |
186 | terminator++; | |
187 | memcpy(terminator, entry, sizeof(struct omfs_extent_entry)); | |
188 | ||
189 | entry->e_cluster = cpu_to_be64(new_block); | |
190 | entry->e_blocks = cpu_to_be64((u64) new_count); | |
191 | ||
192 | terminator->e_blocks = ~(cpu_to_be64( | |
193 | be64_to_cpu(~terminator->e_blocks) + (u64) new_count)); | |
194 | ||
195 | /* write in new entry */ | |
196 | oe->e_extent_count = cpu_to_be32(1 + be32_to_cpu(oe->e_extent_count)); | |
197 | ||
198 | out: | |
199 | *ret_block = new_block; | |
200 | out_fail: | |
201 | return ret; | |
202 | } | |
203 | ||
204 | /* | |
205 | * Scans across the directory table for a given file block number. | |
206 | * If block not found, return 0. | |
207 | */ | |
208 | static sector_t find_block(struct inode *inode, struct omfs_extent_entry *ent, | |
209 | sector_t block, int count, int *left) | |
210 | { | |
211 | /* count > 1 because of terminator */ | |
212 | sector_t searched = 0; | |
213 | for (; count > 1; count--) { | |
214 | int numblocks = clus_to_blk(OMFS_SB(inode->i_sb), | |
215 | be64_to_cpu(ent->e_blocks)); | |
216 | ||
217 | if (block >= searched && | |
218 | block < searched + numblocks) { | |
219 | /* | |
220 | * found it at cluster + (block - searched) | |
221 | * numblocks - (block - searched) is remainder | |
222 | */ | |
223 | *left = numblocks - (block - searched); | |
224 | return clus_to_blk(OMFS_SB(inode->i_sb), | |
225 | be64_to_cpu(ent->e_cluster)) + | |
226 | block - searched; | |
227 | } | |
228 | searched += numblocks; | |
229 | ent++; | |
230 | } | |
231 | return 0; | |
232 | } | |
233 | ||
234 | static int omfs_get_block(struct inode *inode, sector_t block, | |
235 | struct buffer_head *bh_result, int create) | |
236 | { | |
237 | struct buffer_head *bh; | |
238 | sector_t next, offset; | |
239 | int ret; | |
240 | u64 new_block; | |
9419fc1c | 241 | u32 max_extents; |
8f09e987 BC |
242 | int extent_count; |
243 | struct omfs_extent *oe; | |
244 | struct omfs_extent_entry *entry; | |
245 | struct omfs_sb_info *sbi = OMFS_SB(inode->i_sb); | |
246 | int max_blocks = bh_result->b_size >> inode->i_blkbits; | |
247 | int remain; | |
248 | ||
249 | ret = -EIO; | |
250 | bh = sb_bread(inode->i_sb, clus_to_blk(sbi, inode->i_ino)); | |
251 | if (!bh) | |
252 | goto out; | |
253 | ||
254 | oe = (struct omfs_extent *)(&bh->b_data[OMFS_EXTENT_START]); | |
9419fc1c | 255 | max_extents = omfs_max_extents(sbi, OMFS_EXTENT_START); |
8f09e987 BC |
256 | next = inode->i_ino; |
257 | ||
258 | for (;;) { | |
259 | ||
260 | if (omfs_is_bad(sbi, (struct omfs_header *) bh->b_data, next)) | |
261 | goto out_brelse; | |
262 | ||
263 | extent_count = be32_to_cpu(oe->e_extent_count); | |
264 | next = be64_to_cpu(oe->e_next); | |
265 | entry = &oe->e_entry; | |
266 | ||
9419fc1c BC |
267 | if (extent_count > max_extents) |
268 | goto out_brelse; | |
269 | ||
8f09e987 BC |
270 | offset = find_block(inode, entry, block, extent_count, &remain); |
271 | if (offset > 0) { | |
272 | ret = 0; | |
273 | map_bh(bh_result, inode->i_sb, offset); | |
274 | if (remain > max_blocks) | |
275 | remain = max_blocks; | |
276 | bh_result->b_size = (remain << inode->i_blkbits); | |
277 | goto out_brelse; | |
278 | } | |
279 | if (next == ~0) | |
280 | break; | |
281 | ||
282 | brelse(bh); | |
283 | bh = sb_bread(inode->i_sb, clus_to_blk(sbi, next)); | |
284 | if (!bh) | |
285 | goto out; | |
286 | oe = (struct omfs_extent *) (&bh->b_data[OMFS_EXTENT_CONT]); | |
9419fc1c | 287 | max_extents = omfs_max_extents(sbi, OMFS_EXTENT_CONT); |
8f09e987 BC |
288 | } |
289 | if (create) { | |
290 | ret = omfs_grow_extent(inode, oe, &new_block); | |
291 | if (ret == 0) { | |
292 | mark_buffer_dirty(bh); | |
293 | mark_inode_dirty(inode); | |
294 | map_bh(bh_result, inode->i_sb, | |
295 | clus_to_blk(sbi, new_block)); | |
296 | } | |
297 | } | |
298 | out_brelse: | |
299 | brelse(bh); | |
300 | out: | |
301 | return ret; | |
302 | } | |
303 | ||
304 | static int omfs_readpage(struct file *file, struct page *page) | |
305 | { | |
306 | return block_read_full_page(page, omfs_get_block); | |
307 | } | |
308 | ||
309 | static int omfs_readpages(struct file *file, struct address_space *mapping, | |
310 | struct list_head *pages, unsigned nr_pages) | |
311 | { | |
312 | return mpage_readpages(mapping, pages, nr_pages, omfs_get_block); | |
313 | } | |
314 | ||
315 | static int omfs_writepage(struct page *page, struct writeback_control *wbc) | |
316 | { | |
317 | return block_write_full_page(page, omfs_get_block, wbc); | |
318 | } | |
319 | ||
320 | static int | |
321 | omfs_writepages(struct address_space *mapping, struct writeback_control *wbc) | |
322 | { | |
323 | return mpage_writepages(mapping, wbc, omfs_get_block); | |
324 | } | |
325 | ||
326 | static int omfs_write_begin(struct file *file, struct address_space *mapping, | |
327 | loff_t pos, unsigned len, unsigned flags, | |
328 | struct page **pagep, void **fsdata) | |
329 | { | |
330 | *pagep = NULL; | |
331 | return block_write_begin(file, mapping, pos, len, flags, | |
332 | pagep, fsdata, omfs_get_block); | |
333 | } | |
334 | ||
335 | static sector_t omfs_bmap(struct address_space *mapping, sector_t block) | |
336 | { | |
337 | return generic_block_bmap(mapping, block, omfs_get_block); | |
338 | } | |
339 | ||
340 | struct file_operations omfs_file_operations = { | |
341 | .llseek = generic_file_llseek, | |
342 | .read = do_sync_read, | |
343 | .write = do_sync_write, | |
344 | .aio_read = generic_file_aio_read, | |
345 | .aio_write = generic_file_aio_write, | |
346 | .mmap = generic_file_mmap, | |
347 | .fsync = omfs_sync_file, | |
348 | .splice_read = generic_file_splice_read, | |
349 | }; | |
350 | ||
351 | struct inode_operations omfs_file_inops = { | |
352 | .truncate = omfs_truncate | |
353 | }; | |
354 | ||
355 | struct address_space_operations omfs_aops = { | |
356 | .readpage = omfs_readpage, | |
357 | .readpages = omfs_readpages, | |
358 | .writepage = omfs_writepage, | |
359 | .writepages = omfs_writepages, | |
360 | .sync_page = block_sync_page, | |
361 | .write_begin = omfs_write_begin, | |
362 | .write_end = generic_write_end, | |
363 | .bmap = omfs_bmap, | |
364 | }; | |
365 |