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 "reiserfs.h"
17 #include <linux/buffer_head.h>
18
reiserfs_resize(struct super_block * s,unsigned long block_count_new)19 int reiserfs_resize(struct super_block *s, unsigned long block_count_new)
20 {
21 int err = 0;
22 struct reiserfs_super_block *sb;
23 struct reiserfs_bitmap_info *bitmap;
24 struct reiserfs_bitmap_info *info;
25 struct reiserfs_bitmap_info *old_bitmap = SB_AP_BITMAP(s);
26 struct buffer_head *bh;
27 struct reiserfs_transaction_handle th;
28 unsigned int bmap_nr_new, bmap_nr;
29 unsigned int block_r_new, block_r;
30
31 struct reiserfs_list_bitmap *jb;
32 struct reiserfs_list_bitmap jbitmap[JOURNAL_NUM_BITMAPS];
33
34 unsigned long int block_count, free_blocks;
35 int i;
36 int copy_size;
37
38 sb = SB_DISK_SUPER_BLOCK(s);
39
40 if (SB_BLOCK_COUNT(s) >= block_count_new) {
41 printk("can\'t shrink filesystem on-line\n");
42 return -EINVAL;
43 }
44
45 /* check the device size */
46 bh = sb_bread(s, block_count_new - 1);
47 if (!bh) {
48 printk("reiserfs_resize: can\'t read last block\n");
49 return -EINVAL;
50 }
51 bforget(bh);
52
53 /* old disk layout detection; those partitions can be mounted, but
54 * cannot be resized */
55 if (SB_BUFFER_WITH_SB(s)->b_blocknr * SB_BUFFER_WITH_SB(s)->b_size
56 != REISERFS_DISK_OFFSET_IN_BYTES) {
57 printk
58 ("reiserfs_resize: unable to resize a reiserfs without distributed bitmap (fs version < 3.5.12)\n");
59 return -ENOTSUPP;
60 }
61
62 /* count used bits in last bitmap block */
63 block_r = SB_BLOCK_COUNT(s) -
64 (reiserfs_bmap_count(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 = reiserfs_bmap_count(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 return -ENOMEM;
85 }
86 /* the new journal bitmaps are zero filled, now we copy in the bitmap
87 ** node pointers from the old journal bitmap structs, and then
88 ** transfer the new data structures into the journal struct.
89 **
90 ** using the copy_size var below allows this code to work for
91 ** both shrinking and expanding the FS.
92 */
93 copy_size = bmap_nr_new < bmap_nr ? bmap_nr_new : bmap_nr;
94 copy_size =
95 copy_size * sizeof(struct reiserfs_list_bitmap_node *);
96 for (i = 0; i < JOURNAL_NUM_BITMAPS; i++) {
97 struct reiserfs_bitmap_node **node_tmp;
98 jb = SB_JOURNAL(s)->j_list_bitmap + i;
99 memcpy(jbitmap[i].bitmaps, jb->bitmaps, copy_size);
100
101 /* just in case vfree schedules on us, copy the new
102 ** pointer into the journal struct before freeing the
103 ** old one
104 */
105 node_tmp = jb->bitmaps;
106 jb->bitmaps = jbitmap[i].bitmaps;
107 vfree(node_tmp);
108 }
109
110 /* allocate additional bitmap blocks, reallocate array of bitmap
111 * block pointers */
112 bitmap =
113 vzalloc(sizeof(struct reiserfs_bitmap_info) * bmap_nr_new);
114 if (!bitmap) {
115 /* Journal bitmaps are still supersized, but the memory isn't
116 * leaked, so I guess it's ok */
117 printk("reiserfs_resize: unable to allocate memory.\n");
118 return -ENOMEM;
119 }
120 for (i = 0; i < bmap_nr; i++)
121 bitmap[i] = old_bitmap[i];
122
123 /* This doesn't go through the journal, but it doesn't have to.
124 * The changes are still atomic: We're synced up when the journal
125 * transaction begins, and the new bitmaps don't matter if the
126 * transaction fails. */
127 for (i = bmap_nr; i < bmap_nr_new; i++) {
128 /* don't use read_bitmap_block since it will cache
129 * the uninitialized bitmap */
130 bh = sb_bread(s, i * s->s_blocksize * 8);
131 if (!bh) {
132 vfree(bitmap);
133 return -EIO;
134 }
135 memset(bh->b_data, 0, sb_blocksize(sb));
136 reiserfs_set_le_bit(0, bh->b_data);
137 reiserfs_cache_bitmap_metadata(s, bh, bitmap + i);
138
139 set_buffer_uptodate(bh);
140 mark_buffer_dirty(bh);
141 reiserfs_write_unlock(s);
142 sync_dirty_buffer(bh);
143 reiserfs_write_lock(s);
144 // update bitmap_info stuff
145 bitmap[i].free_count = sb_blocksize(sb) * 8 - 1;
146 brelse(bh);
147 }
148 /* free old bitmap blocks array */
149 SB_AP_BITMAP(s) = bitmap;
150 vfree(old_bitmap);
151 }
152
153 /* begin transaction, if there was an error, it's fine. Yes, we have
154 * incorrect bitmaps now, but none of it is ever going to touch the
155 * disk anyway. */
156 err = journal_begin(&th, s, 10);
157 if (err)
158 return err;
159
160 /* Extend old last bitmap block - new blocks have been made available */
161 info = SB_AP_BITMAP(s) + bmap_nr - 1;
162 bh = reiserfs_read_bitmap_block(s, bmap_nr - 1);
163 if (!bh) {
164 int jerr = journal_end(&th, s, 10);
165 if (jerr)
166 return jerr;
167 return -EIO;
168 }
169
170 reiserfs_prepare_for_journal(s, bh, 1);
171 for (i = block_r; i < s->s_blocksize * 8; i++)
172 reiserfs_clear_le_bit(i, bh->b_data);
173 info->free_count += s->s_blocksize * 8 - block_r;
174
175 journal_mark_dirty(&th, s, bh);
176 brelse(bh);
177
178 /* Correct new last bitmap block - It may not be full */
179 info = SB_AP_BITMAP(s) + bmap_nr_new - 1;
180 bh = reiserfs_read_bitmap_block(s, bmap_nr_new - 1);
181 if (!bh) {
182 int jerr = journal_end(&th, s, 10);
183 if (jerr)
184 return jerr;
185 return -EIO;
186 }
187
188 reiserfs_prepare_for_journal(s, bh, 1);
189 for (i = block_r_new; i < s->s_blocksize * 8; i++)
190 reiserfs_set_le_bit(i, bh->b_data);
191 journal_mark_dirty(&th, s, bh);
192 brelse(bh);
193
194 info->free_count -= s->s_blocksize * 8 - block_r_new;
195 /* update super */
196 reiserfs_prepare_for_journal(s, SB_BUFFER_WITH_SB(s), 1);
197 free_blocks = SB_FREE_BLOCKS(s);
198 PUT_SB_FREE_BLOCKS(s,
199 free_blocks + (block_count_new - block_count -
200 (bmap_nr_new - bmap_nr)));
201 PUT_SB_BLOCK_COUNT(s, block_count_new);
202 PUT_SB_BMAP_NR(s, bmap_would_wrap(bmap_nr_new) ? : bmap_nr_new);
203 s->s_dirt = 1;
204
205 journal_mark_dirty(&th, s, SB_BUFFER_WITH_SB(s));
206
207 SB_JOURNAL(s)->j_must_wait = 1;
208 return journal_end(&th, s, 10);
209 }
210