1/*
2 * res_gdt.c --- reserve blocks for growing the group descriptor table
3 *               during online resizing.
4 *
5 * Copyright (C) 2002 Andreas Dilger
6 *
7 * %Begin-Header%
8 * This file may be redistributed under the terms of the GNU Library
9 * General Public License, version 2.
10 * %End-Header%
11 */
12
13#include <stdio.h>
14#include <string.h>
15#include <time.h>
16#include "ext2_fs.h"
17#include "ext2fs.h"
18
19/*
20 * Iterate through the groups which hold BACKUP superblock/GDT copies in an
21 * ext3 filesystem.  The counters should be initialized to 1, 5, and 7 before
22 * calling this for the first time.  In a sparse filesystem it will be the
23 * sequence of powers of 3, 5, and 7: 1, 3, 5, 7, 9, 25, 27, 49, 81, ...
24 * For a non-sparse filesystem it will be every group: 1, 2, 3, 4, ...
25 */
26static unsigned int list_backups(ext2_filsys fs, unsigned int *three,
27				 unsigned int *five, unsigned int *seven)
28{
29	unsigned int *min = three;
30	int mult = 3;
31	unsigned int ret;
32
33	if (!(fs->super->s_feature_ro_compat &
34	      EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER)) {
35		ret = *min;
36		*min += 1;
37		return ret;
38	}
39
40	if (*five < *min) {
41		min = five;
42		mult = 5;
43	}
44	if (*seven < *min) {
45		min = seven;
46		mult = 7;
47	}
48
49	ret = *min;
50	*min *= mult;
51
52	return ret;
53}
54
55/*
56 * This code assumes that the reserved blocks have already been marked in-use
57 * during ext2fs_initialize(), so that they are not allocated for other
58 * uses before we can add them to the resize inode (which has to come
59 * after the creation of the inode table).
60 */
61errcode_t ext2fs_create_resize_inode(ext2_filsys fs)
62{
63	errcode_t		retval, retval2;
64	struct ext2_super_block	*sb;
65	struct ext2_inode	inode;
66	__u32			*dindir_buf, *gdt_buf;
67	unsigned long long	apb, inode_size;
68	/* FIXME-64 - can't deal with extents */
69	blk_t			dindir_blk, rsv_off, gdt_off, gdt_blk;
70	int			dindir_dirty = 0, inode_dirty = 0, sb_blk = 0;
71
72	EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
73
74	sb = fs->super;
75
76	retval = ext2fs_get_array(2, fs->blocksize, &dindir_buf);
77	if (retval)
78		return retval;
79	gdt_buf = (__u32 *)((char *)dindir_buf + fs->blocksize);
80
81	retval = ext2fs_read_inode(fs, EXT2_RESIZE_INO, &inode);
82	if (retval)
83		goto out_free;
84
85	/*
86	 * File systems with a blocksize of 1024 and bigalloc have
87	 * sb->s_first_data_block of 0; yet the superblock is still at
88	 * block #1.  We compensate for it here.
89	 */
90	sb_blk = sb->s_first_data_block;
91	if (fs->blocksize == 1024 && sb_blk == 0)
92		sb_blk = 1;
93
94	/* Maximum possible file size (we donly use the dindirect blocks) */
95	apb = EXT2_ADDR_PER_BLOCK(sb);
96	if ((dindir_blk = inode.i_block[EXT2_DIND_BLOCK])) {
97#ifdef RES_GDT_DEBUG
98		printf("reading GDT dindir %u\n", dindir_blk);
99#endif
100		retval = ext2fs_read_ind_block(fs, dindir_blk, dindir_buf);
101		if (retval)
102			goto out_inode;
103	} else {
104		blk_t goal = sb_blk + fs->desc_blocks +
105			sb->s_reserved_gdt_blocks + 2 +
106			fs->inode_blocks_per_group;
107
108		retval = ext2fs_alloc_block(fs, goal, 0, &dindir_blk);
109		if (retval)
110			goto out_free;
111		inode.i_mode = LINUX_S_IFREG | 0600;
112		inode.i_links_count = 1;
113		inode.i_block[EXT2_DIND_BLOCK] = dindir_blk;
114		ext2fs_iblk_set(fs, &inode, 1);
115		memset(dindir_buf, 0, fs->blocksize);
116#ifdef RES_GDT_DEBUG
117		printf("allocated GDT dindir %u\n", dindir_blk);
118#endif
119		dindir_dirty = inode_dirty = 1;
120		inode_size = apb*apb + apb + EXT2_NDIR_BLOCKS;
121		inode_size *= fs->blocksize;
122		inode.i_size = inode_size & 0xFFFFFFFF;
123		inode.i_size_high = (inode_size >> 32) & 0xFFFFFFFF;
124		if(inode.i_size_high) {
125			sb->s_feature_ro_compat |=
126				EXT2_FEATURE_RO_COMPAT_LARGE_FILE;
127		}
128		inode.i_ctime = fs->now ? fs->now : time(0);
129	}
130
131	for (rsv_off = 0, gdt_off = fs->desc_blocks,
132	     gdt_blk = sb_blk + 1 + fs->desc_blocks;
133	     rsv_off < sb->s_reserved_gdt_blocks;
134	     rsv_off++, gdt_off++, gdt_blk++) {
135		unsigned int three = 1, five = 5, seven = 7;
136		unsigned int grp, last = 0;
137		int gdt_dirty = 0;
138
139		gdt_off %= apb;
140		if (!dindir_buf[gdt_off]) {
141			/* FIXME XXX XXX
142			blk_t new_blk;
143
144			retval = ext2fs_new_block(fs, gdt_blk, 0, &new_blk);
145			if (retval)
146				goto out_free;
147			if (new_blk != gdt_blk) {
148				// XXX free block
149				retval = -1; // XXX
150			}
151			*/
152			gdt_dirty = dindir_dirty = inode_dirty = 1;
153			memset(gdt_buf, 0, fs->blocksize);
154			dindir_buf[gdt_off] = gdt_blk;
155			ext2fs_iblk_add_blocks(fs, &inode, 1);
156#ifdef RES_GDT_DEBUG
157			printf("added primary GDT block %u at %u[%u]\n",
158			       gdt_blk, dindir_blk, gdt_off);
159#endif
160		} else if (dindir_buf[gdt_off] == gdt_blk) {
161#ifdef RES_GDT_DEBUG
162			printf("reading primary GDT block %u\n", gdt_blk);
163#endif
164			retval = ext2fs_read_ind_block(fs, gdt_blk, gdt_buf);
165			if (retval)
166				goto out_dindir;
167		} else {
168#ifdef RES_GDT_DEBUG
169			printf("bad primary GDT %u != %u at %u[%u]\n",
170			       dindir_buf[gdt_off], gdt_blk,dindir_blk,gdt_off);
171#endif
172			retval = EXT2_ET_RESIZE_INODE_CORRUPT;
173			goto out_dindir;
174		}
175
176		while ((grp = list_backups(fs, &three, &five, &seven)) <
177		       fs->group_desc_count) {
178			blk_t expect = gdt_blk + grp * sb->s_blocks_per_group;
179
180			if (!gdt_buf[last]) {
181#ifdef RES_GDT_DEBUG
182				printf("added backup GDT %u grp %u@%u[%u]\n",
183				       expect, grp, gdt_blk, last);
184#endif
185				gdt_buf[last] = expect;
186				ext2fs_iblk_add_blocks(fs, &inode, 1);
187				gdt_dirty = inode_dirty = 1;
188			} else if (gdt_buf[last] != expect) {
189#ifdef RES_GDT_DEBUG
190				printf("bad backup GDT %u != %u at %u[%u]\n",
191				       gdt_buf[last], expect, gdt_blk, last);
192#endif
193				retval = EXT2_ET_RESIZE_INODE_CORRUPT;
194				goto out_dindir;
195			}
196			last++;
197		}
198		if (gdt_dirty) {
199#ifdef RES_GDT_DEBUG
200			printf("writing primary GDT block %u\n", gdt_blk);
201#endif
202			retval = ext2fs_write_ind_block(fs, gdt_blk, gdt_buf);
203			if (retval)
204				goto out_dindir;
205		}
206	}
207
208out_dindir:
209	if (dindir_dirty) {
210		retval2 = ext2fs_write_ind_block(fs, dindir_blk, dindir_buf);
211		if (!retval)
212			retval = retval2;
213	}
214out_inode:
215#ifdef RES_GDT_DEBUG
216	printf("inode.i_blocks = %u, i_size = %u\n", inode.i_blocks,
217	       inode.i_size);
218#endif
219	if (inode_dirty) {
220		inode.i_atime = inode.i_mtime = fs->now ? fs->now : time(0);
221		retval2 = ext2fs_write_new_inode(fs, EXT2_RESIZE_INO, &inode);
222		if (!retval)
223			retval = retval2;
224	}
225out_free:
226	ext2fs_free_mem(&dindir_buf);
227	return retval;
228}
229
230