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
omfs_sync_file(struct file * file,struct dentry * dentry,int datasync)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
omfs_max_extents(struct omfs_sb_info * sbi,int offset)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
omfs_make_empty_table(struct buffer_head * bh,int offset)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
40 oe->e_next = ~cpu_to_be64(0ULL);
41 oe->e_extent_count = cpu_to_be32(1),
42 oe->e_fill = cpu_to_be32(0x22),
43 oe->e_entry.e_cluster = ~cpu_to_be64(0ULL);
44 oe->e_entry.e_blocks = ~cpu_to_be64(0ULL);
45 }
46
omfs_shrink_inode(struct inode * inode)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;
55 u32 max_extents;
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]);
73 max_extents = omfs_max_extents(sbi, OMFS_EXTENT_START);
74
75 for (;;) {
76
77 if (omfs_is_bad(sbi, (struct omfs_header *) bh->b_data, next))
78 goto out_brelse;
79
80 extent_count = be32_to_cpu(oe->e_extent_count);
81
82 if (extent_count > max_extents)
83 goto out_brelse;
84
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]);
112 max_extents = omfs_max_extents(sbi, OMFS_EXTENT_CONT);
113 }
114 ret = 0;
115 out:
116 return ret;
117 out_brelse:
118 brelse(bh);
119 return ret;
120 }
121
omfs_truncate(struct inode * inode)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 */
omfs_grow_extent(struct inode * inode,struct omfs_extent * oe,u64 * ret_block)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 }
172 max_count = omfs_max_extents(sbi, OMFS_EXTENT_START);
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 */
find_block(struct inode * inode,struct omfs_extent_entry * ent,sector_t block,int count,int * left)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
omfs_get_block(struct inode * inode,sector_t block,struct buffer_head * bh_result,int create)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;
241 u32 max_extents;
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]);
255 max_extents = omfs_max_extents(sbi, OMFS_EXTENT_START);
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
267 if (extent_count > max_extents)
268 goto out_brelse;
269
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]);
287 max_extents = omfs_max_extents(sbi, OMFS_EXTENT_CONT);
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
omfs_readpage(struct file * file,struct page * page)304 static int omfs_readpage(struct file *file, struct page *page)
305 {
306 return block_read_full_page(page, omfs_get_block);
307 }
308
omfs_readpages(struct file * file,struct address_space * mapping,struct list_head * pages,unsigned nr_pages)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
omfs_writepage(struct page * page,struct writeback_control * wbc)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
omfs_writepages(struct address_space * mapping,struct writeback_control * wbc)321 omfs_writepages(struct address_space *mapping, struct writeback_control *wbc)
322 {
323 return mpage_writepages(mapping, wbc, omfs_get_block);
324 }
325
omfs_write_begin(struct file * file,struct address_space * mapping,loff_t pos,unsigned len,unsigned flags,struct page ** pagep,void ** fsdata)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
omfs_bmap(struct address_space * mapping,sector_t block)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
366