[PATCH] reiserfs: reorganize bitmap loading functions
[linux-2.6.git] / fs / reiserfs / resize.c
1 /* 
2  * Copyright 2000 by Hans Reiser, licensing governed by reiserfs/README
3  */
4
5 /* 
6  * Written by Alexander Zarochentcev.
7  *
8  * The kernel part of the (on-line) reiserfs resizer.
9  */
10
11 #include <linux/kernel.h>
12 #include <linux/mm.h>
13 #include <linux/vmalloc.h>
14 #include <linux/string.h>
15 #include <linux/errno.h>
16 #include <linux/reiserfs_fs.h>
17 #include <linux/reiserfs_fs_sb.h>
18 #include <linux/buffer_head.h>
19
20 int reiserfs_resize(struct super_block *s, unsigned long block_count_new)
21 {
22         int err = 0;
23         struct reiserfs_super_block *sb;
24         struct reiserfs_bitmap_info *bitmap;
25         struct reiserfs_bitmap_info *info;
26         struct reiserfs_bitmap_info *old_bitmap = SB_AP_BITMAP(s);
27         struct buffer_head *bh;
28         struct reiserfs_transaction_handle th;
29         unsigned int bmap_nr_new, bmap_nr;
30         unsigned int block_r_new, block_r;
31
32         struct reiserfs_list_bitmap *jb;
33         struct reiserfs_list_bitmap jbitmap[JOURNAL_NUM_BITMAPS];
34
35         unsigned long int block_count, free_blocks;
36         int i;
37         int copy_size;
38
39         sb = SB_DISK_SUPER_BLOCK(s);
40
41         if (SB_BLOCK_COUNT(s) >= block_count_new) {
42                 printk("can\'t shrink filesystem on-line\n");
43                 return -EINVAL;
44         }
45
46         /* check the device size */
47         bh = sb_bread(s, block_count_new - 1);
48         if (!bh) {
49                 printk("reiserfs_resize: can\'t read last block\n");
50                 return -EINVAL;
51         }
52         bforget(bh);
53
54         /* old disk layout detection; those partitions can be mounted, but
55          * cannot be resized */
56         if (SB_BUFFER_WITH_SB(s)->b_blocknr * SB_BUFFER_WITH_SB(s)->b_size
57             != REISERFS_DISK_OFFSET_IN_BYTES) {
58                 printk
59                     ("reiserfs_resize: unable to resize a reiserfs without distributed bitmap (fs version < 3.5.12)\n");
60                 return -ENOTSUPP;
61         }
62
63         /* count used bits in last bitmap block */
64         block_r = SB_BLOCK_COUNT(s) - (SB_BMAP_NR(s) - 1) * s->s_blocksize * 8;
65
66         /* count bitmap blocks in new fs */
67         bmap_nr_new = block_count_new / (s->s_blocksize * 8);
68         block_r_new = block_count_new - bmap_nr_new * s->s_blocksize * 8;
69         if (block_r_new)
70                 bmap_nr_new++;
71         else
72                 block_r_new = s->s_blocksize * 8;
73
74         /* save old values */
75         block_count = SB_BLOCK_COUNT(s);
76         bmap_nr = SB_BMAP_NR(s);
77
78         /* resizing of reiserfs bitmaps (journal and real), if needed */
79         if (bmap_nr_new > bmap_nr) {
80                 /* reallocate journal bitmaps */
81                 if (reiserfs_allocate_list_bitmaps(s, jbitmap, bmap_nr_new) < 0) {
82                         printk
83                             ("reiserfs_resize: unable to allocate memory for journal bitmaps\n");
84                         unlock_super(s);
85                         return -ENOMEM;
86                 }
87                 /* the new journal bitmaps are zero filled, now we copy in the bitmap
88                  ** node pointers from the old journal bitmap structs, and then
89                  ** transfer the new data structures into the journal struct.
90                  **
91                  ** using the copy_size var below allows this code to work for
92                  ** both shrinking and expanding the FS.
93                  */
94                 copy_size = bmap_nr_new < bmap_nr ? bmap_nr_new : bmap_nr;
95                 copy_size =
96                     copy_size * sizeof(struct reiserfs_list_bitmap_node *);
97                 for (i = 0; i < JOURNAL_NUM_BITMAPS; i++) {
98                         struct reiserfs_bitmap_node **node_tmp;
99                         jb = SB_JOURNAL(s)->j_list_bitmap + i;
100                         memcpy(jbitmap[i].bitmaps, jb->bitmaps, copy_size);
101
102                         /* just in case vfree schedules on us, copy the new
103                          ** pointer into the journal struct before freeing the 
104                          ** old one
105                          */
106                         node_tmp = jb->bitmaps;
107                         jb->bitmaps = jbitmap[i].bitmaps;
108                         vfree(node_tmp);
109                 }
110
111                 /* allocate additional bitmap blocks, reallocate array of bitmap
112                  * block pointers */
113                 bitmap =
114                     vmalloc(sizeof(struct reiserfs_bitmap_info) * bmap_nr_new);
115                 if (!bitmap) {
116                         /* Journal bitmaps are still supersized, but the memory isn't
117                          * leaked, so I guess it's ok */
118                         printk("reiserfs_resize: unable to allocate memory.\n");
119                         return -ENOMEM;
120                 }
121                 memset(bitmap, 0,
122                        sizeof(struct reiserfs_bitmap_info) * SB_BMAP_NR(s));
123                 for (i = 0; i < bmap_nr; i++)
124                         bitmap[i] = old_bitmap[i];
125
126                 /* This doesn't go through the journal, but it doesn't have to.
127                  * The changes are still atomic: We're synced up when the journal
128                  * transaction begins, and the new bitmaps don't matter if the
129                  * transaction fails. */
130                 for (i = bmap_nr; i < bmap_nr_new; i++) {
131                         bh = sb_getblk(s, i * s->s_blocksize * 8);
132                         get_bh(bh);
133                         memset(bh->b_data, 0, sb_blocksize(sb));
134                         reiserfs_test_and_set_le_bit(0, bh->b_data);
135                         reiserfs_cache_bitmap_metadata(s, bh, bitmap + i);
136
137                         set_buffer_uptodate(bh);
138                         mark_buffer_dirty(bh);
139                         sync_dirty_buffer(bh);
140                         // update bitmap_info stuff
141                         bitmap[i].first_zero_hint = 1;
142                         bitmap[i].free_count = sb_blocksize(sb) * 8 - 1;
143                         bitmap[i].bh = bh;
144                         brelse(bh);
145                 }
146                 /* free old bitmap blocks array */
147                 SB_AP_BITMAP(s) = bitmap;
148                 vfree(old_bitmap);
149         }
150
151         /* begin transaction, if there was an error, it's fine. Yes, we have
152          * incorrect bitmaps now, but none of it is ever going to touch the
153          * disk anyway. */
154         err = journal_begin(&th, s, 10);
155         if (err)
156                 return err;
157
158         /* Extend old last bitmap block - new blocks have been made available */
159         info = SB_AP_BITMAP(s) + bmap_nr - 1;
160         bh = info->bh;
161         get_bh(bh);
162
163         reiserfs_prepare_for_journal(s, bh, 1);
164         for (i = block_r; i < s->s_blocksize * 8; i++)
165                 reiserfs_test_and_clear_le_bit(i, bh->b_data);
166         info->free_count += s->s_blocksize * 8 - block_r;
167         if (!info->first_zero_hint)
168                 info->first_zero_hint = block_r;
169
170         journal_mark_dirty(&th, s, bh);
171         brelse(bh);
172
173         /* Correct new last bitmap block - It may not be full */
174         info = SB_AP_BITMAP(s) + bmap_nr_new - 1;
175         bh = info->bh;
176         get_bh(bh);
177
178         reiserfs_prepare_for_journal(s, bh, 1);
179         for (i = block_r_new; i < s->s_blocksize * 8; i++)
180                 reiserfs_test_and_set_le_bit(i, bh->b_data);
181         journal_mark_dirty(&th, s, bh);
182         brelse(bh);
183
184         info->free_count -= s->s_blocksize * 8 - block_r_new;
185         /* Extreme case where last bitmap is the only valid block in itself. */
186         if (!info->free_count)
187                 info->first_zero_hint = 0;
188         /* update super */
189         reiserfs_prepare_for_journal(s, SB_BUFFER_WITH_SB(s), 1);
190         free_blocks = SB_FREE_BLOCKS(s);
191         PUT_SB_FREE_BLOCKS(s,
192                            free_blocks + (block_count_new - block_count -
193                                           (bmap_nr_new - bmap_nr)));
194         PUT_SB_BLOCK_COUNT(s, block_count_new);
195         PUT_SB_BMAP_NR(s, bmap_nr_new);
196         s->s_dirt = 1;
197
198         journal_mark_dirty(&th, s, SB_BUFFER_WITH_SB(s));
199
200         SB_JOURNAL(s)->j_must_wait = 1;
201         return journal_end(&th, s, 10);
202 }