2 * OMFS (as used by RIO Karma) file operations.
3 * Copyright (C) 2005 Bob Copeland <me@bobcopeland.com>
4 * Released under GPL v2.
7 #include <linux/version.h>
8 #include <linux/module.h>
10 #include <linux/buffer_head.h>
11 #include <linux/mpage.h>
14 static u32
omfs_max_extents(struct omfs_sb_info
*sbi
, int offset
)
16 return (sbi
->s_sys_blocksize
- offset
-
17 sizeof(struct omfs_extent
)) /
18 sizeof(struct omfs_extent_entry
) + 1;
21 void omfs_make_empty_table(struct buffer_head
*bh
, int offset
)
23 struct omfs_extent
*oe
= (struct omfs_extent
*) &bh
->b_data
[offset
];
25 oe
->e_next
= ~cpu_to_be64(0ULL);
26 oe
->e_extent_count
= cpu_to_be32(1),
27 oe
->e_fill
= cpu_to_be32(0x22),
28 oe
->e_entry
.e_cluster
= ~cpu_to_be64(0ULL);
29 oe
->e_entry
.e_blocks
= ~cpu_to_be64(0ULL);
32 int omfs_shrink_inode(struct inode
*inode
)
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
;
43 /* traverse extent table, freeing each entry that is greater
48 /* only support truncate -> 0 for now */
50 if (inode
->i_size
!= 0)
53 bh
= omfs_bread(inode
->i_sb
, next
);
57 oe
= (struct omfs_extent
*)(&bh
->b_data
[OMFS_EXTENT_START
]);
58 max_extents
= omfs_max_extents(sbi
, OMFS_EXTENT_START
);
62 if (omfs_is_bad(sbi
, (struct omfs_header
*) bh
->b_data
, next
))
65 extent_count
= be32_to_cpu(oe
->e_extent_count
);
67 if (extent_count
> max_extents
)
71 next
= be64_to_cpu(oe
->e_next
);
74 /* ignore last entry as it is the terminator */
75 for (; extent_count
> 1; extent_count
--) {
77 start
= be64_to_cpu(entry
->e_cluster
);
78 count
= be64_to_cpu(entry
->e_blocks
);
80 omfs_clear_range(inode
->i_sb
, start
, (int) count
);
83 omfs_make_empty_table(bh
, (char *) oe
- bh
->b_data
);
84 mark_buffer_dirty(bh
);
87 if (last
!= inode
->i_ino
)
88 omfs_clear_range(inode
->i_sb
, last
, sbi
->s_mirrors
);
93 bh
= omfs_bread(inode
->i_sb
, next
);
96 oe
= (struct omfs_extent
*) (&bh
->b_data
[OMFS_EXTENT_CONT
]);
97 max_extents
= omfs_max_extents(sbi
, OMFS_EXTENT_CONT
);
107 static void omfs_truncate(struct inode
*inode
)
109 omfs_shrink_inode(inode
);
110 mark_inode_dirty(inode
);
114 * Add new blocks to the current extent, or create new entries/continuations
117 static int omfs_grow_extent(struct inode
*inode
, struct omfs_extent
*oe
,
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
);
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
136 /* TODO: handle holes */
138 /* should always have a terminator */
139 if (extent_count
< 1)
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
);
149 if (omfs_allocate_block(inode
->i_sb
, new_block
)) {
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));
157 max_count
= omfs_max_extents(sbi
, OMFS_EXTENT_START
);
159 /* TODO: add a continuation block here */
160 if (be32_to_cpu(oe
->e_extent_count
) > max_count
-1)
163 /* try to allocate a new cluster */
164 ret
= omfs_allocate_range(inode
->i_sb
, 1, sbi
->s_clustersize
,
165 &new_block
, &new_count
);
169 /* copy terminator down an entry */
172 memcpy(terminator
, entry
, sizeof(struct omfs_extent_entry
));
174 entry
->e_cluster
= cpu_to_be64(new_block
);
175 entry
->e_blocks
= cpu_to_be64((u64
) new_count
);
177 terminator
->e_blocks
= ~(cpu_to_be64(
178 be64_to_cpu(~terminator
->e_blocks
) + (u64
) new_count
));
180 /* write in new entry */
181 oe
->e_extent_count
= cpu_to_be32(1 + be32_to_cpu(oe
->e_extent_count
));
184 *ret_block
= new_block
;
190 * Scans across the directory table for a given file block number.
191 * If block not found, return 0.
193 static sector_t
find_block(struct inode
*inode
, struct omfs_extent_entry
*ent
,
194 sector_t block
, int count
, int *left
)
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
));
202 if (block
>= searched
&&
203 block
< searched
+ numblocks
) {
205 * found it at cluster + (block - searched)
206 * numblocks - (block - searched) is remainder
208 *left
= numblocks
- (block
- searched
);
209 return clus_to_blk(OMFS_SB(inode
->i_sb
),
210 be64_to_cpu(ent
->e_cluster
)) +
213 searched
+= numblocks
;
219 static int omfs_get_block(struct inode
*inode
, sector_t block
,
220 struct buffer_head
*bh_result
, int create
)
222 struct buffer_head
*bh
;
223 sector_t next
, offset
;
225 u64
uninitialized_var(new_block
);
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
;
235 bh
= omfs_bread(inode
->i_sb
, inode
->i_ino
);
239 oe
= (struct omfs_extent
*)(&bh
->b_data
[OMFS_EXTENT_START
]);
240 max_extents
= omfs_max_extents(sbi
, OMFS_EXTENT_START
);
245 if (omfs_is_bad(sbi
, (struct omfs_header
*) bh
->b_data
, next
))
248 extent_count
= be32_to_cpu(oe
->e_extent_count
);
249 next
= be64_to_cpu(oe
->e_next
);
250 entry
= &oe
->e_entry
;
252 if (extent_count
> max_extents
)
255 offset
= find_block(inode
, entry
, block
, extent_count
, &remain
);
258 map_bh(bh_result
, inode
->i_sb
, offset
);
259 if (remain
> max_blocks
)
261 bh_result
->b_size
= (remain
<< inode
->i_blkbits
);
268 bh
= omfs_bread(inode
->i_sb
, next
);
271 oe
= (struct omfs_extent
*) (&bh
->b_data
[OMFS_EXTENT_CONT
]);
272 max_extents
= omfs_max_extents(sbi
, OMFS_EXTENT_CONT
);
275 ret
= omfs_grow_extent(inode
, oe
, &new_block
);
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
));
289 static int omfs_readpage(struct file
*file
, struct page
*page
)
291 return block_read_full_page(page
, omfs_get_block
);
294 static int omfs_readpages(struct file
*file
, struct address_space
*mapping
,
295 struct list_head
*pages
, unsigned nr_pages
)
297 return mpage_readpages(mapping
, pages
, nr_pages
, omfs_get_block
);
300 static int omfs_writepage(struct page
*page
, struct writeback_control
*wbc
)
302 return block_write_full_page(page
, omfs_get_block
, wbc
);
306 omfs_writepages(struct address_space
*mapping
, struct writeback_control
*wbc
)
308 return mpage_writepages(mapping
, wbc
, omfs_get_block
);
311 static 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
)
317 ret
= block_write_begin(mapping
, pos
, len
, flags
, pagep
,
320 loff_t isize
= mapping
->host
->i_size
;
321 if (pos
+ len
> isize
)
322 vmtruncate(mapping
->host
, isize
);
328 static sector_t
omfs_bmap(struct address_space
*mapping
, sector_t block
)
330 return generic_block_bmap(mapping
, block
, omfs_get_block
);
333 const struct file_operations omfs_file_operations
= {
334 .llseek
= generic_file_llseek
,
335 .read
= do_sync_read
,
336 .write
= do_sync_write
,
337 .aio_read
= generic_file_aio_read
,
338 .aio_write
= generic_file_aio_write
,
339 .mmap
= generic_file_mmap
,
340 .fsync
= generic_file_fsync
,
341 .splice_read
= generic_file_splice_read
,
344 static int omfs_setattr(struct dentry
*dentry
, struct iattr
*attr
)
346 struct inode
*inode
= dentry
->d_inode
;
349 error
= inode_change_ok(inode
, attr
);
353 if ((attr
->ia_valid
& ATTR_SIZE
) &&
354 attr
->ia_size
!= i_size_read(inode
)) {
355 error
= vmtruncate(inode
, attr
->ia_size
);
360 setattr_copy(inode
, attr
);
361 mark_inode_dirty(inode
);
365 const struct inode_operations omfs_file_inops
= {
366 .setattr
= omfs_setattr
,
367 .truncate
= omfs_truncate
370 const struct address_space_operations omfs_aops
= {
371 .readpage
= omfs_readpage
,
372 .readpages
= omfs_readpages
,
373 .writepage
= omfs_writepage
,
374 .writepages
= omfs_writepages
,
375 .sync_page
= block_sync_page
,
376 .write_begin
= omfs_write_begin
,
377 .write_end
= generic_write_end
,