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