/* * Copyright (C) 2010 The Android Open Source Project * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ #include "ext4_utils.h" #include "ext4_extents.h" #include "allocate.h" #include "ext4fixup.h" #include #include #include #include #include #include #include #if defined(__APPLE__) && defined(__MACH__) #define lseek64 lseek #define off64_t off_t #endif /* The inode block count for a file/directory is in units of 512 byte blocks, * _NOT_ the filesystem block size! */ #define INODE_BLOCK_SIZE 512 #define MAX_EXT4_BLOCK_SIZE 4096 /* The two modes the recurse_dir() can be in */ #define SANITY_CHECK_PASS 1 #define MARK_INODE_NUMS 2 #define UPDATE_INODE_NUMS 3 /* Magic numbers to indicate what state the update process is in */ #define MAGIC_STATE_MARKING_INUMS 0x7000151515565512ll #define MAGIC_STATE_UPDATING_INUMS 0x6121131211735123ll #define MAGIC_STATE_UPDATING_SB 0x15e1715151558477ll /* Internal state variables corresponding to the magic numbers */ #define STATE_UNSET 0 #define STATE_MARKING_INUMS 1 #define STATE_UPDATING_INUMS 2 #define STATE_UPDATING_SB 3 /* Used for automated testing of this programs ability to stop and be restarted wthout error */ static int bail_phase = 0; static int bail_loc = 0; static int bail_count = 0; static int count = 0; /* global flags */ static int verbose = 0; static int no_write = 0; static int new_inodes_per_group = 0; static int no_write_fixup_state = 0; static int compute_new_inum(unsigned int old_inum) { unsigned int group, offset; group = (old_inum - 1) / info.inodes_per_group; offset = (old_inum -1) % info.inodes_per_group; return (group * new_inodes_per_group) + offset + 1; } static int get_fs_fixup_state(int fd) { unsigned long long magic; int ret, len; if (no_write) { return no_write_fixup_state; } lseek64(fd, 0, SEEK_SET); len = read(fd, &magic, sizeof(magic)); if (len != sizeof(magic)) { critical_error("cannot read fixup_state\n"); } switch (magic) { case MAGIC_STATE_MARKING_INUMS: ret = STATE_MARKING_INUMS; break; case MAGIC_STATE_UPDATING_INUMS: ret = STATE_UPDATING_INUMS; break; case MAGIC_STATE_UPDATING_SB: ret = STATE_UPDATING_SB; break; default: ret = STATE_UNSET; } return ret; } static int set_fs_fixup_state(int fd, int state) { unsigned long long magic; struct ext4_super_block sb; int len; if (no_write) { no_write_fixup_state = state; return 0; } switch (state) { case STATE_MARKING_INUMS: magic = MAGIC_STATE_MARKING_INUMS; break; case STATE_UPDATING_INUMS: magic = MAGIC_STATE_UPDATING_INUMS; break; case STATE_UPDATING_SB: magic = MAGIC_STATE_UPDATING_SB; break; case STATE_UNSET: default: magic = 0ll; break; } lseek64(fd, 0, SEEK_SET); len = write(fd, &magic, sizeof(magic)); if (len != sizeof(magic)) { critical_error("cannot write fixup_state\n"); } read_sb(fd, &sb); if (magic) { /* If we are in the process of updating the filesystem, make it unmountable */ sb.s_desc_size |= 1; } else { /* we are done, so make the filesystem mountable again */ sb.s_desc_size &= ~1; } if (!no_write) { write_sb(fd, 1024, &sb); } return 0; } static int read_inode(int fd, unsigned int inum, struct ext4_inode *inode) { unsigned int bg_num, bg_offset; off64_t inode_offset; int len; bg_num = (inum-1) / info.inodes_per_group; bg_offset = (inum-1) % info.inodes_per_group; inode_offset = ((unsigned long long)aux_info.bg_desc[bg_num].bg_inode_table * info.block_size) + (bg_offset * info.inode_size); if (lseek64(fd, inode_offset, SEEK_SET) < 0) { critical_error_errno("failed to seek to inode %d\n", inum); } len=read(fd, inode, sizeof(*inode)); if (len != sizeof(*inode)) { critical_error_errno("failed to read inode %d\n", inum); } return 0; } static int read_block(int fd, unsigned long long block_num, void *block) { off64_t off; unsigned int len; off = block_num * info.block_size; if (lseek64(fd, off, SEEK_SET) , 0) { critical_error_errno("failed to seek to block %lld\n", block_num); } len=read(fd, block, info.block_size); if (len != info.block_size) { critical_error_errno("failed to read block %lld\n", block_num); } return 0; } static int write_block(int fd, unsigned long long block_num, void *block) { off64_t off; unsigned int len; if (no_write) { return 0; } off = block_num * info.block_size; if (lseek64(fd, off, SEEK_SET) < 0) { critical_error_errno("failed to seek to block %lld\n", block_num); } len=write(fd, block, info.block_size); if (len != info.block_size) { critical_error_errno("failed to write block %lld\n", block_num); } return 0; } static void check_inode_bitmap(int fd, unsigned int bg_num) { unsigned int inode_bitmap_block_num; unsigned char block[MAX_EXT4_BLOCK_SIZE]; int i, bitmap_updated = 0; /* Using the bg_num, aux_info.bg_desc[], info.inodes_per_group and * new_inodes_per_group, retrieve the inode bitmap, and make sure * the bits between the old and new size are clear */ inode_bitmap_block_num = aux_info.bg_desc[bg_num].bg_inode_bitmap; read_block(fd, inode_bitmap_block_num, block); for (i = info.inodes_per_group; i < new_inodes_per_group; i++) { if (bitmap_get_bit(block, i)) { bitmap_clear_bit(block, i); bitmap_updated = 1; } } if (bitmap_updated) { if (verbose) { printf("Warning: updated inode bitmap for block group %d\n", bg_num); } write_block(fd, inode_bitmap_block_num, block); } return; } /* Update the superblock and bgdesc of the specified block group */ static int update_superblocks_and_bg_desc(int fd, int state) { off64_t ret; struct ext4_super_block sb; unsigned int num_block_groups, total_new_inodes; unsigned int i; read_sb(fd, &sb); /* Compute how many more inodes are now available */ num_block_groups = DIV_ROUND_UP(aux_info.len_blocks, info.blocks_per_group); total_new_inodes = num_block_groups * (new_inodes_per_group - sb.s_inodes_per_group); if (verbose) { printf("created %d additional inodes\n", total_new_inodes); } /* Update the free inodes count in each block group descriptor */ for (i = 0; i < num_block_groups; i++) { if (state == STATE_UPDATING_SB) { aux_info.bg_desc[i].bg_free_inodes_count += (new_inodes_per_group - sb.s_inodes_per_group); } check_inode_bitmap(fd, i); } /* First some sanity checks */ if ((sb.s_inodes_count + total_new_inodes) != (new_inodes_per_group * num_block_groups)) { critical_error("Failed sanity check on new inode count\n"); } if (new_inodes_per_group % (info.block_size/info.inode_size)) { critical_error("Failed sanity check on new inode per group alignment\n"); } /* Update the free inodes count in the superblock */ sb.s_inodes_count += total_new_inodes; sb.s_free_inodes_count += total_new_inodes; sb.s_inodes_per_group = new_inodes_per_group; for (i = 0; i < aux_info.groups; i++) { if (ext4_bg_has_super_block(i)) { unsigned int sb_offset; if (i == 0) { /* The first superblock is offset by 1K to leave room for boot sectors */ sb_offset = 1024; } else { sb_offset = 0; } sb.s_block_group_nr = i; /* Don't write out the backup superblocks with the bit set in the s_desc_size * which prevents the filesystem from mounting. The bit for the primary * superblock will be cleared on the final call to set_fs_fixup_state() */ if (i != 0) { sb.s_desc_size &= ~1; } if (!no_write) { write_sb(fd, (unsigned long long)i * info.blocks_per_group * info.block_size + sb_offset, &sb); } ret = lseek64(fd, ((unsigned long long)i * info.blocks_per_group * info.block_size) + (info.block_size * (aux_info.first_data_block + 1)), SEEK_SET); if (ret < 0) critical_error_errno("failed to seek to block group descriptors"); if (!no_write) { ret = write(fd, aux_info.bg_desc, info.block_size * aux_info.bg_desc_blocks); if (ret < 0) critical_error_errno("failed to write block group descriptors"); if (ret != (int)info.block_size * (int)aux_info.bg_desc_blocks) critical_error("failed to write all of block group descriptors"); } } if ((bail_phase == 4) && ((unsigned int)bail_count == i)) { critical_error("bailing at phase 4\n"); } } return 0; } static int get_direct_blocks(struct ext4_inode *inode, unsigned long long *block_list, unsigned int *count) { unsigned int i = 0; unsigned int ret = 0; unsigned int sectors_per_block; sectors_per_block = info.block_size / INODE_BLOCK_SIZE; while ((i < (inode->i_blocks_lo / sectors_per_block)) && (i < EXT4_NDIR_BLOCKS)) { block_list[i] = inode->i_block[i]; i++; } *count += i; if ((inode->i_blocks_lo / sectors_per_block) > EXT4_NDIR_BLOCKS) { ret = 1; } return ret; } static int get_indirect_blocks(int fd, struct ext4_inode *inode, unsigned long long *block_list, unsigned int *count) { unsigned int i; unsigned int *indirect_block; unsigned int sectors_per_block; sectors_per_block = info.block_size / INODE_BLOCK_SIZE; indirect_block = (unsigned int *)malloc(info.block_size); if (indirect_block == 0) { critical_error("failed to allocate memory for indirect_block\n"); } read_block(fd, inode->i_block[EXT4_NDIR_BLOCKS], indirect_block); for(i = 0; i < (inode->i_blocks_lo / sectors_per_block - EXT4_NDIR_BLOCKS); i++) { block_list[EXT4_NDIR_BLOCKS+i] = indirect_block[i]; } *count += i; free(indirect_block); return 0; } static int get_block_list_indirect(int fd, struct ext4_inode *inode, unsigned long long *block_list) { unsigned int count=0; if (get_direct_blocks(inode, block_list, &count)) { get_indirect_blocks(fd, inode, block_list, &count); } return count; } static int get_extent_ents(struct ext4_extent_header *ext_hdr, unsigned long long *block_list) { int i, j; struct ext4_extent *extent; off64_t fs_block_num; if (ext_hdr->eh_depth != 0) { critical_error("get_extent_ents called with eh_depth != 0\n"); } /* The extent entries immediately follow the header, so add 1 to the pointer * and cast it to an extent pointer. */ extent = (struct ext4_extent *)(ext_hdr + 1); for (i = 0; i < ext_hdr->eh_entries; i++) { fs_block_num = ((off64_t)extent->ee_start_hi << 32) | extent->ee_start_lo; for (j = 0; j < extent->ee_len; j++) { block_list[extent->ee_block+j] = fs_block_num+j; } extent++; } return 0; } static int get_extent_idx(int fd, struct ext4_extent_header *ext_hdr, unsigned long long *block_list) { int i; struct ext4_extent_idx *extent_idx; struct ext4_extent_header *tmp_ext_hdr; off64_t fs_block_num; unsigned char block[MAX_EXT4_BLOCK_SIZE]; /* Sanity check */ if (ext_hdr->eh_depth == 0) { critical_error("get_extent_idx called with eh_depth == 0\n"); } /* The extent entries immediately follow the header, so add 1 to the pointer * and cast it to an extent pointer. */ extent_idx = (struct ext4_extent_idx *)(ext_hdr + 1); for (i = 0; i < ext_hdr->eh_entries; i++) { fs_block_num = ((off64_t)extent_idx->ei_leaf_hi << 32) | extent_idx->ei_leaf_lo; read_block(fd, fs_block_num, block); tmp_ext_hdr = (struct ext4_extent_header *)block; if (tmp_ext_hdr->eh_depth == 0) { get_extent_ents(tmp_ext_hdr, block_list); /* leaf node, fill in block_list */ } else { get_extent_idx(fd, tmp_ext_hdr, block_list); /* recurse down the tree */ } } return 0; } static int get_block_list_extents(int fd, struct ext4_inode *inode, unsigned long long *block_list) { struct ext4_extent_header *extent_hdr; extent_hdr = (struct ext4_extent_header *)inode->i_block; if (extent_hdr->eh_magic != EXT4_EXT_MAGIC) { critical_error("extent header has unexpected magic value 0x%4.4x\n", extent_hdr->eh_magic); } if (extent_hdr->eh_depth == 0) { get_extent_ents((struct ext4_extent_header *)inode->i_block, block_list); return 0; } get_extent_idx(fd, (struct ext4_extent_header *)inode->i_block, block_list); return 0; } static int is_entry_dir(int fd, struct ext4_dir_entry_2 *dirp, int pass) { struct ext4_inode inode; int ret = 0; if (dirp->file_type == EXT4_FT_DIR) { ret = 1; } else if (dirp->file_type == EXT4_FT_UNKNOWN) { /* Somebody was too lazy to fill in the dir entry, * so we have to go fetch it from the inode. Grrr. */ /* if UPDATE_INODE_NUMS pass and the inode high bit is not * set return false so we don't recurse down the tree that is * already updated. Otherwise, fetch inode, and return answer. */ if ((pass == UPDATE_INODE_NUMS) && !(dirp->inode & 0x80000000)) { ret = 0; } else { read_inode(fd, (dirp->inode & 0x7fffffff), &inode); if (S_ISDIR(inode.i_mode)) { ret = 1; } } } return ret; } static int recurse_dir(int fd, struct ext4_inode *inode, char *dirbuf, int dirsize, int mode) { unsigned long long *block_list; unsigned int num_blocks; struct ext4_dir_entry_2 *dirp, *prev_dirp = 0; char name[256]; unsigned int i, leftover_space, is_dir; struct ext4_inode tmp_inode; int tmp_dirsize; char *tmp_dirbuf; switch (mode) { case SANITY_CHECK_PASS: case MARK_INODE_NUMS: case UPDATE_INODE_NUMS: break; default: critical_error("recurse_dir() called witn unknown mode!\n"); } if (dirsize % info.block_size) { critical_error("dirsize %d not a multiple of block_size %d. This is unexpected!\n", dirsize, info.block_size); } num_blocks = dirsize / info.block_size; block_list = malloc((num_blocks + 1) * sizeof(*block_list)); if (block_list == 0) { critical_error("failed to allocate memory for block_list\n"); } if (inode->i_flags & EXT4_EXTENTS_FL) { get_block_list_extents(fd, inode, block_list); } else { /* A directory that requires doubly or triply indirect blocks in huge indeed, * and will almost certainly not exist, especially since make_ext4fs only creates * directories with extents, and the kernel will too, but check to make sure the * directory is not that big and give an error if so. Our limit is 12 direct blocks, * plus block_size/4 singly indirect blocks, which for a filesystem with 4K blocks * is a directory 1036 blocks long, or 4,243,456 bytes long! Assuming an average * filename length of 20 (which I think is generous) thats 20 + 8 bytes overhead * per entry, or 151,552 entries in the directory! */ if (num_blocks > (info.block_size / 4 + EXT4_NDIR_BLOCKS)) { critical_error("Non-extent based directory is too big!\n"); } get_block_list_indirect(fd, inode, block_list); } /* Read in all the blocks for this directory */ for (i = 0; i < num_blocks; i++) { read_block(fd, block_list[i], dirbuf + (i * info.block_size)); } dirp = (struct ext4_dir_entry_2 *)dirbuf; while (dirp < (struct ext4_dir_entry_2 *)(dirbuf + dirsize)) { count++; leftover_space = (char *)(dirbuf + dirsize) - (char *)dirp; if (((mode == SANITY_CHECK_PASS) || (mode == UPDATE_INODE_NUMS)) && (leftover_space <= 8) && prev_dirp) { /* This is a bug in an older version of make_ext4fs, where it * didn't properly include the rest of the block in rec_len. * Update rec_len on the previous entry to include the rest of * the block and exit the loop. */ if (verbose) { printf("fixing up short rec_len for diretory entry for %s\n", name); } prev_dirp->rec_len += leftover_space; break; } if (dirp->inode == 0) { /* This is the last entry in the directory */ break; } strncpy(name, dirp->name, dirp->name_len); name[dirp->name_len]='\0'; /* Only recurse on pass UPDATE_INODE_NUMS if the high bit is set. * Otherwise, this inode entry has already been updated * and we'll do the wrong thing. Also don't recurse on . or .., * and certainly not on non-directories! */ /* Hrm, looks like filesystems made by fastboot on stingray set the file_type * flag, but the lost+found directory has the type set to Unknown, which * seems to imply I need to read the inode and get it. */ is_dir = is_entry_dir(fd, dirp, mode); if ( is_dir && (strcmp(name, ".") && strcmp(name, "..")) && ((mode == SANITY_CHECK_PASS) || (mode == MARK_INODE_NUMS) || ((mode == UPDATE_INODE_NUMS) && (dirp->inode & 0x80000000))) ) { /* A directory! Recurse! */ read_inode(fd, dirp->inode & 0x7fffffff, &tmp_inode); if (!S_ISDIR(tmp_inode.i_mode)) { critical_error("inode %d for name %s does not point to a directory\n", dirp->inode & 0x7fffffff, name); } if (verbose) { printf("inode %d %s use extents\n", dirp->inode & 0x7fffffff, (tmp_inode.i_flags & EXT4_EXTENTS_FL) ? "does" : "does not"); } tmp_dirsize = tmp_inode.i_blocks_lo * INODE_BLOCK_SIZE; if (verbose) { printf("dir size = %d bytes\n", tmp_dirsize); } tmp_dirbuf = malloc(tmp_dirsize); if (tmp_dirbuf == 0) { critical_error("failed to allocate memory for tmp_dirbuf\n"); } recurse_dir(fd, &tmp_inode, tmp_dirbuf, tmp_dirsize, mode); free(tmp_dirbuf); } if (verbose) { if (is_dir) { printf("Directory %s\n", name); } else { printf("Non-directory %s\n", name); } } /* Process entry based on current mode. Either set high bit or change inode number */ if (mode == MARK_INODE_NUMS) { dirp->inode |= 0x80000000; } else if (mode == UPDATE_INODE_NUMS) { if (dirp->inode & 0x80000000) { dirp->inode = compute_new_inum(dirp->inode & 0x7fffffff); } } if ((bail_phase == mode) && (bail_loc == 1) && (bail_count == count)) { critical_error("Bailing at phase %d, loc 1 and count %d\n", mode, count); } /* Point dirp at the next entry */ prev_dirp = dirp; dirp = (struct ext4_dir_entry_2*)((char *)dirp + dirp->rec_len); } /* Write out all the blocks for this directory */ for (i = 0; i < num_blocks; i++) { write_block(fd, block_list[i], dirbuf + (i * info.block_size)); if ((bail_phase == mode) && (bail_loc == 2) && (bail_count <= count)) { critical_error("Bailing at phase %d, loc 2 and count %d\n", mode, count); } } free(block_list); return 0; } int ext4fixup(char *fsdev) { return ext4fixup_internal(fsdev, 0, 0, 0, 0, 0); } int ext4fixup_internal(char *fsdev, int v_flag, int n_flag, int stop_phase, int stop_loc, int stop_count) { int fd; struct ext4_inode root_inode; unsigned int dirsize; char *dirbuf; if (setjmp(setjmp_env)) return EXIT_FAILURE; /* Handle a call to longjmp() */ verbose = v_flag; no_write = n_flag; bail_phase = stop_phase; bail_loc = stop_loc; bail_count = stop_count; fd = open(fsdev, O_RDWR); if (fd < 0) critical_error_errno("failed to open filesystem image"); read_ext(fd, verbose); if (info.feat_incompat & EXT4_FEATURE_INCOMPAT_RECOVER) { critical_error("Filesystem needs recovery first, mount and unmount to do that\n"); } /* Clear the low bit which is set while this tool is in progress. * If the tool crashes, it will still be set when we restart. * The low bit is set to make the filesystem unmountable while * it is being fixed up. Also allow 0, which means the old ext2 * size is in use. */ if (((aux_info.sb->s_desc_size & ~1) != sizeof(struct ext2_group_desc)) && ((aux_info.sb->s_desc_size & ~1) != 0)) critical_error("error: bg_desc_size != sizeof(struct ext2_group_desc)\n"); if ((info.feat_incompat & EXT4_FEATURE_INCOMPAT_FILETYPE) == 0) { critical_error("Expected filesystem to have filetype flag set\n"); } #if 0 // If we have to fix the directory rec_len issue, we can't use this check /* Check to see if the inodes/group is copacetic */ if (info.inodes_per_blockgroup % (info.block_size/info.inode_size) == 0) { /* This filesystem has either already been updated, or was * made correctly. */ if (verbose) { printf("%s: filesystem correct, no work to do\n", me); } exit(0); } #endif /* Compute what the new value of inodes_per_blockgroup will be when we're done */ new_inodes_per_group=EXT4_ALIGN(info.inodes_per_group,(info.block_size/info.inode_size)); read_inode(fd, EXT4_ROOT_INO, &root_inode); if (!S_ISDIR(root_inode.i_mode)) { critical_error("root inode %d does not point to a directory\n", EXT4_ROOT_INO); } if (verbose) { printf("inode %d %s use extents\n", EXT4_ROOT_INO, (root_inode.i_flags & EXT4_EXTENTS_FL) ? "does" : "does not"); } dirsize = root_inode.i_blocks_lo * INODE_BLOCK_SIZE; if (verbose) { printf("root dir size = %d bytes\n", dirsize); } dirbuf = malloc(dirsize); if (dirbuf == 0) { critical_error("failed to allocate memory for dirbuf\n"); } /* Perform a sanity check pass first, try to catch any errors that will occur * before we actually change anything, so we don't leave a filesystem in a * corrupted, unrecoverable state. Set no_write, make it quiet, and do a recurse * pass and a update_superblock pass. Set flags back to requested state when done. * Only perform sanity check if the state is unset. If the state is _NOT_ unset, * then the tool has already been run and interrupted, and it presumably ran and * passed sanity checked before it got interrupted. It is _NOT_ safe to run sanity * check if state is unset because it assumes inodes are to be computed using the * old inodes/group, but some inode numbers may be updated to the new number. */ if (get_fs_fixup_state(fd) == STATE_UNSET) { verbose = 0; no_write = 1; recurse_dir(fd, &root_inode, dirbuf, dirsize, SANITY_CHECK_PASS); update_superblocks_and_bg_desc(fd, STATE_UNSET); verbose = v_flag; no_write = n_flag; set_fs_fixup_state(fd, STATE_MARKING_INUMS); } if (get_fs_fixup_state(fd) == STATE_MARKING_INUMS) { count = 0; /* Reset debugging counter */ if (!recurse_dir(fd, &root_inode, dirbuf, dirsize, MARK_INODE_NUMS)) { set_fs_fixup_state(fd, STATE_UPDATING_INUMS); } } if (get_fs_fixup_state(fd) == STATE_UPDATING_INUMS) { count = 0; /* Reset debugging counter */ if (!recurse_dir(fd, &root_inode, dirbuf, dirsize, UPDATE_INODE_NUMS)) { set_fs_fixup_state(fd, STATE_UPDATING_SB); } } if (get_fs_fixup_state(fd) == STATE_UPDATING_SB) { /* set the new inodes/blockgroup number, * and sets the state back to 0. */ if (!update_superblocks_and_bg_desc(fd, STATE_UPDATING_SB)) { set_fs_fixup_state(fd, STATE_UNSET); } } close(fd); return 0; }