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