diff options
Diffstat (limited to 'lib/ext2fs/res_gdt.c')
| -rw-r--r-- | lib/ext2fs/res_gdt.c | 239 |
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; +} + |