[PATCH] hfsplus: don't modify journaled volume
[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 *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) - (SB_BMAP_NR(s) - 1) * s->s_blocksize * 8;
64
65         /* count bitmap blocks in new fs */
66         bmap_nr_new = block_count_new / (s->s_blocksize * 8);
67         block_r_new = block_count_new - bmap_nr_new * s->s_blocksize * 8;
68         if (block_r_new)
69                 bmap_nr_new++;
70         else
71                 block_r_new = s->s_blocksize * 8;
72
73         /* save old values */
74         block_count = SB_BLOCK_COUNT(s);
75         bmap_nr = SB_BMAP_NR(s);
76
77         /* resizing of reiserfs bitmaps (journal and real), if needed */
78         if (bmap_nr_new > bmap_nr) {
79                 /* reallocate journal bitmaps */
80                 if (reiserfs_allocate_list_bitmaps(s, jbitmap, bmap_nr_new) < 0) {
81                         printk
82                             ("reiserfs_resize: unable to allocate memory for journal bitmaps\n");
83                         unlock_super(s);
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                     vmalloc(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                 memset(bitmap, 0,
121                        sizeof(struct reiserfs_bitmap_info) * SB_BMAP_NR(s));
122                 for (i = 0; i < bmap_nr; i++)
123                         bitmap[i] = old_bitmap[i];
124
125                 /* This doesn't go through the journal, but it doesn't have to.
126                  * The changes are still atomic: We're synced up when the journal
127                  * transaction begins, and the new bitmaps don't matter if the
128                  * transaction fails. */
129                 for (i = bmap_nr; i < bmap_nr_new; i++) {
130                         bitmap[i].bh = sb_getblk(s, i * s->s_blocksize * 8);
131                         memset(bitmap[i].bh->b_data, 0, sb_blocksize(sb));
132                         reiserfs_test_and_set_le_bit(0, bitmap[i].bh->b_data);
133
134                         set_buffer_uptodate(bitmap[i].bh);
135                         mark_buffer_dirty(bitmap[i].bh);
136                         sync_dirty_buffer(bitmap[i].bh);
137                         // update bitmap_info stuff
138                         bitmap[i].first_zero_hint = 1;
139                         bitmap[i].free_count = sb_blocksize(sb) * 8 - 1;
140                 }
141                 /* free old bitmap blocks array */
142                 SB_AP_BITMAP(s) = bitmap;
143                 vfree(old_bitmap);
144         }
145
146         /* begin transaction, if there was an error, it's fine. Yes, we have
147          * incorrect bitmaps now, but none of it is ever going to touch the
148          * disk anyway. */
149         err = journal_begin(&th, s, 10);
150         if (err)
151                 return err;
152
153         /* correct last bitmap blocks in old and new disk layout */
154         reiserfs_prepare_for_journal(s, SB_AP_BITMAP(s)[bmap_nr - 1].bh, 1);
155         for (i = block_r; i < s->s_blocksize * 8; i++)
156                 reiserfs_test_and_clear_le_bit(i,
157                                                SB_AP_BITMAP(s)[bmap_nr -
158                                                                1].bh->b_data);
159         SB_AP_BITMAP(s)[bmap_nr - 1].free_count += s->s_blocksize * 8 - block_r;
160         if (!SB_AP_BITMAP(s)[bmap_nr - 1].first_zero_hint)
161                 SB_AP_BITMAP(s)[bmap_nr - 1].first_zero_hint = block_r;
162
163         journal_mark_dirty(&th, s, SB_AP_BITMAP(s)[bmap_nr - 1].bh);
164
165         reiserfs_prepare_for_journal(s, SB_AP_BITMAP(s)[bmap_nr_new - 1].bh, 1);
166         for (i = block_r_new; i < s->s_blocksize * 8; i++)
167                 reiserfs_test_and_set_le_bit(i,
168                                              SB_AP_BITMAP(s)[bmap_nr_new -
169                                                              1].bh->b_data);
170         journal_mark_dirty(&th, s, SB_AP_BITMAP(s)[bmap_nr_new - 1].bh);
171
172         SB_AP_BITMAP(s)[bmap_nr_new - 1].free_count -=
173             s->s_blocksize * 8 - block_r_new;
174         /* Extreme case where last bitmap is the only valid block in itself. */
175         if (!SB_AP_BITMAP(s)[bmap_nr_new - 1].free_count)
176                 SB_AP_BITMAP(s)[bmap_nr_new - 1].first_zero_hint = 0;
177         /* update super */
178         reiserfs_prepare_for_journal(s, SB_BUFFER_WITH_SB(s), 1);
179         free_blocks = SB_FREE_BLOCKS(s);
180         PUT_SB_FREE_BLOCKS(s,
181                            free_blocks + (block_count_new - block_count -
182                                           (bmap_nr_new - bmap_nr)));
183         PUT_SB_BLOCK_COUNT(s, block_count_new);
184         PUT_SB_BMAP_NR(s, bmap_nr_new);
185         s->s_dirt = 1;
186
187         journal_mark_dirty(&th, s, SB_BUFFER_WITH_SB(s));
188
189         SB_JOURNAL(s)->j_must_wait = 1;
190         return journal_end(&th, s, 10);
191 }