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-rw-r--r--lib/ext2fs/res_gdt.c239
1 files changed, 239 insertions, 0 deletions
diff --git a/lib/ext2fs/res_gdt.c b/lib/ext2fs/res_gdt.c
new file mode 100644
index 0000000..fa8d8d6
--- /dev/null
+++ b/lib/ext2fs/res_gdt.c
@@ -0,0 +1,239 @@
+/*
+ * res_gdt.c --- reserve blocks for growing the group descriptor table
+ * during online resizing.
+ *
+ * Copyright (C) 2002 Andreas Dilger
+ *
+ * %Begin-Header%
+ * This file may be redistributed under the terms of the GNU Library
+ * General Public License, version 2.
+ * %End-Header%
+ */
+
+#include "config.h"
+#include <stdio.h>
+#include <string.h>
+#include <time.h>
+#include "ext2_fs.h"
+#include "ext2fs.h"
+
+/*
+ * Iterate through the groups which hold BACKUP superblock/GDT copies in an
+ * ext3 filesystem. The counters should be initialized to 1, 5, and 7 before
+ * calling this for the first time. In a sparse filesystem it will be the
+ * sequence of powers of 3, 5, and 7: 1, 3, 5, 7, 9, 25, 27, 49, 81, ...
+ * For a non-sparse filesystem it will be every group: 1, 2, 3, 4, ...
+ */
+static unsigned int list_backups(ext2_filsys fs, unsigned int *three,
+ unsigned int *five, unsigned int *seven)
+{
+ unsigned int *min = three;
+ int mult = 3;
+ unsigned int ret;
+
+ if (ext2fs_has_feature_sparse_super2(fs->super)) {
+ if (*min == 1) {
+ *min += 1;
+ if (fs->super->s_backup_bgs[0])
+ return fs->super->s_backup_bgs[0];
+ }
+ if (*min == 2) {
+ *min += 1;
+ if (fs->super->s_backup_bgs[1])
+ return fs->super->s_backup_bgs[1];
+ }
+ return fs->group_desc_count;
+ }
+ if (!ext2fs_has_feature_sparse_super(fs->super)) {
+ ret = *min;
+ *min += 1;
+ return ret;
+ }
+
+ if (*five < *min) {
+ min = five;
+ mult = 5;
+ }
+ if (*seven < *min) {
+ min = seven;
+ mult = 7;
+ }
+
+ ret = *min;
+ *min *= mult;
+
+ return ret;
+}
+
+/*
+ * This code assumes that the reserved blocks have already been marked in-use
+ * during ext2fs_initialize(), so that they are not allocated for other
+ * uses before we can add them to the resize inode (which has to come
+ * after the creation of the inode table).
+ */
+errcode_t ext2fs_create_resize_inode(ext2_filsys fs)
+{
+ errcode_t retval, retval2;
+ struct ext2_super_block *sb;
+ struct ext2_inode inode;
+ __u32 *dindir_buf, *gdt_buf;
+ unsigned long long apb, inode_size;
+ /* FIXME-64 - can't deal with extents */
+ blk_t dindir_blk, rsv_off, gdt_off, gdt_blk;
+ int dindir_dirty = 0, inode_dirty = 0, sb_blk = 0;
+
+ EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
+
+ sb = fs->super;
+
+ retval = ext2fs_get_array(2, fs->blocksize, &dindir_buf);
+ if (retval)
+ return retval;
+ gdt_buf = (__u32 *)((char *)dindir_buf + fs->blocksize);
+
+ retval = ext2fs_read_inode(fs, EXT2_RESIZE_INO, &inode);
+ if (retval)
+ goto out_free;
+
+ /*
+ * File systems with a blocksize of 1024 and bigalloc have
+ * sb->s_first_data_block of 0; yet the superblock is still at
+ * block #1. We compensate for it here.
+ */
+ sb_blk = sb->s_first_data_block;
+ if (fs->blocksize == 1024 && sb_blk == 0)
+ sb_blk = 1;
+
+ /* Maximum possible file size (we only use double indirect blocks) */
+ apb = EXT2_ADDR_PER_BLOCK(sb);
+ if ((dindir_blk = inode.i_block[EXT2_DIND_BLOCK])) {
+#ifdef RES_GDT_DEBUG
+ printf("reading GDT dindir %u\n", dindir_blk);
+#endif
+ retval = ext2fs_read_ind_block(fs, dindir_blk, dindir_buf);
+ if (retval)
+ goto out_inode;
+ } else {
+ blk_t goal = sb_blk + fs->desc_blocks +
+ sb->s_reserved_gdt_blocks + 2 +
+ fs->inode_blocks_per_group;
+
+ retval = ext2fs_alloc_block(fs, goal, 0, &dindir_blk);
+ if (retval)
+ goto out_free;
+ inode.i_mode = LINUX_S_IFREG | 0600;
+ inode.i_links_count = 1;
+ inode.i_block[EXT2_DIND_BLOCK] = dindir_blk;
+ ext2fs_iblk_set(fs, &inode, 1);
+ memset(dindir_buf, 0, fs->blocksize);
+#ifdef RES_GDT_DEBUG
+ printf("allocated GDT dindir %u\n", dindir_blk);
+#endif
+ dindir_dirty = inode_dirty = 1;
+ inode_size = apb*apb + apb + EXT2_NDIR_BLOCKS;
+ inode_size *= fs->blocksize;
+ retval = ext2fs_inode_size_set(fs, &inode, inode_size);
+ if (retval)
+ goto out_free;
+ inode.i_ctime = fs->now ? fs->now : time(0);
+ }
+
+ for (rsv_off = 0, gdt_off = fs->desc_blocks,
+ gdt_blk = sb_blk + 1 + fs->desc_blocks;
+ rsv_off < sb->s_reserved_gdt_blocks;
+ rsv_off++, gdt_off++, gdt_blk++) {
+ unsigned int three = 1, five = 5, seven = 7;
+ unsigned int grp, last = 0;
+ int gdt_dirty = 0;
+
+ gdt_off %= apb;
+ if (!dindir_buf[gdt_off]) {
+ /* FIXME XXX XXX
+ blk_t new_blk;
+
+ retval = ext2fs_new_block(fs, gdt_blk, 0, &new_blk);
+ if (retval)
+ goto out_free;
+ if (new_blk != gdt_blk) {
+ // XXX free block
+ retval = -1; // XXX
+ }
+ */
+ gdt_dirty = dindir_dirty = inode_dirty = 1;
+ memset(gdt_buf, 0, fs->blocksize);
+ dindir_buf[gdt_off] = gdt_blk;
+ ext2fs_iblk_add_blocks(fs, &inode, 1);
+#ifdef RES_GDT_DEBUG
+ printf("added primary GDT block %u at %u[%u]\n",
+ gdt_blk, dindir_blk, gdt_off);
+#endif
+ } else if (dindir_buf[gdt_off] == gdt_blk) {
+#ifdef RES_GDT_DEBUG
+ printf("reading primary GDT block %u\n", gdt_blk);
+#endif
+ retval = ext2fs_read_ind_block(fs, gdt_blk, gdt_buf);
+ if (retval)
+ goto out_dindir;
+ } else {
+#ifdef RES_GDT_DEBUG
+ printf("bad primary GDT %u != %u at %u[%u]\n",
+ dindir_buf[gdt_off], gdt_blk,dindir_blk,gdt_off);
+#endif
+ retval = EXT2_ET_RESIZE_INODE_CORRUPT;
+ goto out_dindir;
+ }
+
+ while ((grp = list_backups(fs, &three, &five, &seven)) <
+ fs->group_desc_count) {
+ blk_t expect = gdt_blk + grp * sb->s_blocks_per_group;
+
+ if (!gdt_buf[last]) {
+#ifdef RES_GDT_DEBUG
+ printf("added backup GDT %u grp %u@%u[%u]\n",
+ expect, grp, gdt_blk, last);
+#endif
+ gdt_buf[last] = expect;
+ ext2fs_iblk_add_blocks(fs, &inode, 1);
+ gdt_dirty = inode_dirty = 1;
+ } else if (gdt_buf[last] != expect) {
+#ifdef RES_GDT_DEBUG
+ printf("bad backup GDT %u != %u at %u[%u]\n",
+ gdt_buf[last], expect, gdt_blk, last);
+#endif
+ retval = EXT2_ET_RESIZE_INODE_CORRUPT;
+ goto out_dindir;
+ }
+ last++;
+ }
+ if (gdt_dirty) {
+#ifdef RES_GDT_DEBUG
+ printf("writing primary GDT block %u\n", gdt_blk);
+#endif
+ retval = ext2fs_write_ind_block(fs, gdt_blk, gdt_buf);
+ if (retval)
+ goto out_dindir;
+ }
+ }
+
+out_dindir:
+ if (dindir_dirty) {
+ retval2 = ext2fs_write_ind_block(fs, dindir_blk, dindir_buf);
+ if (!retval)
+ retval = retval2;
+ }
+out_inode:
+#ifdef RES_GDT_DEBUG
+ printf("inode.i_blocks = %u, i_size = %lu\n", inode.i_blocks,
+ EXT2_I_SIZE(&inode));
+#endif
+ if (inode_dirty) {
+ inode.i_atime = inode.i_mtime = fs->now ? fs->now : time(0);
+ retval2 = ext2fs_write_new_inode(fs, EXT2_RESIZE_INO, &inode);
+ if (!retval)
+ retval = retval2;
+ }
+out_free:
+ ext2fs_free_mem(&dindir_buf);
+ return retval;
+}
+