blob: 399487c093646a86ea910756d127d53e4e813668 [file] [log] [blame]
Bob Copeland8f09e982008-07-25 19:45:16 -07001/*
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
Bob Copeland9419fc12008-08-15 00:40:47 -070014static u32 omfs_max_extents(struct omfs_sb_info *sbi, int offset)
15{
16 return (sbi->s_sys_blocksize - offset -
17 sizeof(struct omfs_extent)) /
18 sizeof(struct omfs_extent_entry) + 1;
19}
20
Bob Copeland8f09e982008-07-25 19:45:16 -070021void omfs_make_empty_table(struct buffer_head *bh, int offset)
22{
23 struct omfs_extent *oe = (struct omfs_extent *) &bh->b_data[offset];
24
Harvey Harrisond406f662008-07-29 22:33:46 -070025 oe->e_next = ~cpu_to_be64(0ULL);
Bob Copeland8f09e982008-07-25 19:45:16 -070026 oe->e_extent_count = cpu_to_be32(1),
27 oe->e_fill = cpu_to_be32(0x22),
Harvey Harrisond406f662008-07-29 22:33:46 -070028 oe->e_entry.e_cluster = ~cpu_to_be64(0ULL);
29 oe->e_entry.e_blocks = ~cpu_to_be64(0ULL);
Bob Copeland8f09e982008-07-25 19:45:16 -070030}
31
32int omfs_shrink_inode(struct inode *inode)
33{
34 struct omfs_sb_info *sbi = OMFS_SB(inode->i_sb);
35 struct omfs_extent *oe;
36 struct omfs_extent_entry *entry;
37 struct buffer_head *bh;
38 u64 next, last;
39 u32 extent_count;
Bob Copeland9419fc12008-08-15 00:40:47 -070040 u32 max_extents;
Bob Copeland8f09e982008-07-25 19:45:16 -070041 int ret;
42
43 /* traverse extent table, freeing each entry that is greater
44 * than inode->i_size;
45 */
46 next = inode->i_ino;
47
48 /* only support truncate -> 0 for now */
49 ret = -EIO;
50 if (inode->i_size != 0)
51 goto out;
52
53 bh = sb_bread(inode->i_sb, clus_to_blk(sbi, next));
54 if (!bh)
55 goto out;
56
57 oe = (struct omfs_extent *)(&bh->b_data[OMFS_EXTENT_START]);
Bob Copeland9419fc12008-08-15 00:40:47 -070058 max_extents = omfs_max_extents(sbi, OMFS_EXTENT_START);
Bob Copeland8f09e982008-07-25 19:45:16 -070059
60 for (;;) {
61
Bob Copeland9419fc12008-08-15 00:40:47 -070062 if (omfs_is_bad(sbi, (struct omfs_header *) bh->b_data, next))
63 goto out_brelse;
Bob Copeland8f09e982008-07-25 19:45:16 -070064
65 extent_count = be32_to_cpu(oe->e_extent_count);
Bob Copeland9419fc12008-08-15 00:40:47 -070066
67 if (extent_count > max_extents)
68 goto out_brelse;
69
Bob Copeland8f09e982008-07-25 19:45:16 -070070 last = next;
71 next = be64_to_cpu(oe->e_next);
72 entry = &oe->e_entry;
73
74 /* ignore last entry as it is the terminator */
75 for (; extent_count > 1; extent_count--) {
76 u64 start, count;
77 start = be64_to_cpu(entry->e_cluster);
78 count = be64_to_cpu(entry->e_blocks);
79
80 omfs_clear_range(inode->i_sb, start, (int) count);
81 entry++;
82 }
83 omfs_make_empty_table(bh, (char *) oe - bh->b_data);
84 mark_buffer_dirty(bh);
85 brelse(bh);
86
87 if (last != inode->i_ino)
88 omfs_clear_range(inode->i_sb, last, sbi->s_mirrors);
89
90 if (next == ~0)
91 break;
92
93 bh = sb_bread(inode->i_sb, clus_to_blk(sbi, next));
94 if (!bh)
95 goto out;
96 oe = (struct omfs_extent *) (&bh->b_data[OMFS_EXTENT_CONT]);
Bob Copeland9419fc12008-08-15 00:40:47 -070097 max_extents = omfs_max_extents(sbi, OMFS_EXTENT_CONT);
Bob Copeland8f09e982008-07-25 19:45:16 -070098 }
99 ret = 0;
100out:
101 return ret;
Bob Copeland9419fc12008-08-15 00:40:47 -0700102out_brelse:
103 brelse(bh);
104 return ret;
Bob Copeland8f09e982008-07-25 19:45:16 -0700105}
106
107static 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 */
117static 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 }
Bob Copeland9419fc12008-08-15 00:40:47 -0700157 max_count = omfs_max_extents(sbi, OMFS_EXTENT_START);
Bob Copeland8f09e982008-07-25 19:45:16 -0700158
159 /* TODO: add a continuation block here */
160 if (be32_to_cpu(oe->e_extent_count) > max_count-1)
161 return -EIO;
162
163 /* try to allocate a new cluster */
164 ret = omfs_allocate_range(inode->i_sb, 1, sbi->s_clustersize,
165 &new_block, &new_count);
166 if (ret)
167 goto out_fail;
168
169 /* copy terminator down an entry */
170 entry = terminator;
171 terminator++;
172 memcpy(terminator, entry, sizeof(struct omfs_extent_entry));
173
174 entry->e_cluster = cpu_to_be64(new_block);
175 entry->e_blocks = cpu_to_be64((u64) new_count);
176
177 terminator->e_blocks = ~(cpu_to_be64(
178 be64_to_cpu(~terminator->e_blocks) + (u64) new_count));
179
180 /* write in new entry */
181 oe->e_extent_count = cpu_to_be32(1 + be32_to_cpu(oe->e_extent_count));
182
183out:
184 *ret_block = new_block;
185out_fail:
186 return ret;
187}
188
189/*
190 * Scans across the directory table for a given file block number.
191 * If block not found, return 0.
192 */
193static sector_t find_block(struct inode *inode, struct omfs_extent_entry *ent,
194 sector_t block, int count, int *left)
195{
196 /* count > 1 because of terminator */
197 sector_t searched = 0;
198 for (; count > 1; count--) {
199 int numblocks = clus_to_blk(OMFS_SB(inode->i_sb),
200 be64_to_cpu(ent->e_blocks));
201
202 if (block >= searched &&
203 block < searched + numblocks) {
204 /*
205 * found it at cluster + (block - searched)
206 * numblocks - (block - searched) is remainder
207 */
208 *left = numblocks - (block - searched);
209 return clus_to_blk(OMFS_SB(inode->i_sb),
210 be64_to_cpu(ent->e_cluster)) +
211 block - searched;
212 }
213 searched += numblocks;
214 ent++;
215 }
216 return 0;
217}
218
219static int omfs_get_block(struct inode *inode, sector_t block,
220 struct buffer_head *bh_result, int create)
221{
222 struct buffer_head *bh;
223 sector_t next, offset;
224 int ret;
225 u64 new_block;
Bob Copeland9419fc12008-08-15 00:40:47 -0700226 u32 max_extents;
Bob Copeland8f09e982008-07-25 19:45:16 -0700227 int extent_count;
228 struct omfs_extent *oe;
229 struct omfs_extent_entry *entry;
230 struct omfs_sb_info *sbi = OMFS_SB(inode->i_sb);
231 int max_blocks = bh_result->b_size >> inode->i_blkbits;
232 int remain;
233
234 ret = -EIO;
235 bh = sb_bread(inode->i_sb, clus_to_blk(sbi, inode->i_ino));
236 if (!bh)
237 goto out;
238
239 oe = (struct omfs_extent *)(&bh->b_data[OMFS_EXTENT_START]);
Bob Copeland9419fc12008-08-15 00:40:47 -0700240 max_extents = omfs_max_extents(sbi, OMFS_EXTENT_START);
Bob Copeland8f09e982008-07-25 19:45:16 -0700241 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
Bob Copeland9419fc12008-08-15 00:40:47 -0700252 if (extent_count > max_extents)
253 goto out_brelse;
254
Bob Copeland8f09e982008-07-25 19:45:16 -0700255 offset = find_block(inode, entry, block, extent_count, &remain);
256 if (offset > 0) {
257 ret = 0;
258 map_bh(bh_result, inode->i_sb, offset);
259 if (remain > max_blocks)
260 remain = max_blocks;
261 bh_result->b_size = (remain << inode->i_blkbits);
262 goto out_brelse;
263 }
264 if (next == ~0)
265 break;
266
267 brelse(bh);
268 bh = sb_bread(inode->i_sb, clus_to_blk(sbi, next));
269 if (!bh)
270 goto out;
271 oe = (struct omfs_extent *) (&bh->b_data[OMFS_EXTENT_CONT]);
Bob Copeland9419fc12008-08-15 00:40:47 -0700272 max_extents = omfs_max_extents(sbi, OMFS_EXTENT_CONT);
Bob Copeland8f09e982008-07-25 19:45:16 -0700273 }
274 if (create) {
275 ret = omfs_grow_extent(inode, oe, &new_block);
276 if (ret == 0) {
277 mark_buffer_dirty(bh);
278 mark_inode_dirty(inode);
279 map_bh(bh_result, inode->i_sb,
280 clus_to_blk(sbi, new_block));
281 }
282 }
283out_brelse:
284 brelse(bh);
285out:
286 return ret;
287}
288
289static int omfs_readpage(struct file *file, struct page *page)
290{
291 return block_read_full_page(page, omfs_get_block);
292}
293
294static int omfs_readpages(struct file *file, struct address_space *mapping,
295 struct list_head *pages, unsigned nr_pages)
296{
297 return mpage_readpages(mapping, pages, nr_pages, omfs_get_block);
298}
299
300static int omfs_writepage(struct page *page, struct writeback_control *wbc)
301{
302 return block_write_full_page(page, omfs_get_block, wbc);
303}
304
305static int
306omfs_writepages(struct address_space *mapping, struct writeback_control *wbc)
307{
308 return mpage_writepages(mapping, wbc, omfs_get_block);
309}
310
311static int omfs_write_begin(struct file *file, struct address_space *mapping,
312 loff_t pos, unsigned len, unsigned flags,
313 struct page **pagep, void **fsdata)
314{
315 *pagep = NULL;
316 return block_write_begin(file, mapping, pos, len, flags,
317 pagep, fsdata, omfs_get_block);
318}
319
320static sector_t omfs_bmap(struct address_space *mapping, sector_t block)
321{
322 return generic_block_bmap(mapping, block, omfs_get_block);
323}
324
Alexey Dobriyan828c0952009-10-01 15:43:56 -0700325const struct file_operations omfs_file_operations = {
Bob Copeland8f09e982008-07-25 19:45:16 -0700326 .llseek = generic_file_llseek,
327 .read = do_sync_read,
328 .write = do_sync_write,
329 .aio_read = generic_file_aio_read,
330 .aio_write = generic_file_aio_write,
331 .mmap = generic_file_mmap,
Al Virobea6b642009-06-07 15:44:50 -0400332 .fsync = simple_fsync,
Bob Copeland8f09e982008-07-25 19:45:16 -0700333 .splice_read = generic_file_splice_read,
334};
335
Alexey Dobriyan6e1d5dc2009-09-21 17:01:11 -0700336const struct inode_operations omfs_file_inops = {
Bob Copeland8f09e982008-07-25 19:45:16 -0700337 .truncate = omfs_truncate
338};
339
Alexey Dobriyan7f094102009-09-21 17:01:10 -0700340const struct address_space_operations omfs_aops = {
Bob Copeland8f09e982008-07-25 19:45:16 -0700341 .readpage = omfs_readpage,
342 .readpages = omfs_readpages,
343 .writepage = omfs_writepage,
344 .writepages = omfs_writepages,
345 .sync_page = block_sync_page,
346 .write_begin = omfs_write_begin,
347 .write_end = generic_write_end,
348 .bmap = omfs_bmap,
349};
350