fs/squashfs/inode.c

0001 // SPDX-License-Identifier: GPL-2.0-or-later
0002 /*
0003  * Squashfs - a compressed read only filesystem for Linux
0004  *
0005  * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008
0006  * Phillip Lougher <phillip@squashfs.org.uk>
0007  *
0008  * inode.c
0009  */
0010
0011 /*
0012  * This file implements code to create and read inodes from disk.
0013  *
0014  * Inodes in Squashfs are identified by a 48-bit inode which encodes the
0015  * location of the compressed metadata block containing the inode, and the byte
0016  * offset into that block where the inode is placed (<block, offset>).
0017  *
0018  * To maximise compression there are different inodes for each file type
0019  * (regular file, directory, device, etc.), the inode contents and length
0020  * varying with the type.
0021  *
0022  * To further maximise compression, two types of regular file inode and
0023  * directory inode are defined: inodes optimised for frequently occurring
0024  * regular files and directories, and extended types where extra
0025  * information has to be stored.
0026  */
0027
0028 #include <linux/fs.h>
0029 #include <linux/vfs.h>
0030 #include <linux/xattr.h>
0031 #include <linux/pagemap.h>
0032
0033 #include "squashfs_fs.h"
0034 #include "squashfs_fs_sb.h"
0035 #include "squashfs_fs_i.h"
0036 #include "squashfs.h"
0037 #include "xattr.h"
0038
0039 /*
0040  * Initialise VFS inode with the base inode information common to all
0041  * Squashfs inode types.  Sqsh_ino contains the unswapped base inode
0042  * off disk.
0043  */
0044 static int squashfs_new_inode(struct super_block *sb, struct inode *inode,
0045                 struct squashfs_base_inode *sqsh_ino)
0046 {
0047     uid_t i_uid;
0048     gid_t i_gid;
0049     int err;
0050
0051     err = squashfs_get_id(sb, le16_to_cpu(sqsh_ino->uid), &i_uid);
0052     if (err)
0053         return err;
0054
0055     err = squashfs_get_id(sb, le16_to_cpu(sqsh_ino->guid), &i_gid);
0056     if (err)
0057         return err;
0058
0059     i_uid_write(inode, i_uid);
0060     i_gid_write(inode, i_gid);
0061     inode->i_ino = le32_to_cpu(sqsh_ino->inode_number);
0062     inode->i_mtime.tv_sec = le32_to_cpu(sqsh_ino->mtime);
0063     inode->i_atime.tv_sec = inode->i_mtime.tv_sec;
0064     inode->i_ctime.tv_sec = inode->i_mtime.tv_sec;
0065     inode->i_mode = le16_to_cpu(sqsh_ino->mode);
0066     inode->i_size = 0;
0067
0068     return err;
0069 }
0070
0071
0072 struct inode *squashfs_iget(struct super_block *sb, long long ino,
0073                 unsigned int ino_number)
0074 {
0075     struct inode *inode = iget_locked(sb, ino_number);
0076     int err;
0077
0078     TRACE("Entered squashfs_iget\n");
0079
0080     if (!inode)
0081         return ERR_PTR(-ENOMEM);
0082     if (!(inode->i_state & I_NEW))
0083         return inode;
0084
0085     err = squashfs_read_inode(inode, ino);
0086     if (err) {
0087         iget_failed(inode);
0088         return ERR_PTR(err);
0089     }
0090
0091     unlock_new_inode(inode);
0092     return inode;
0093 }
0094
0095
0096 /*
0097  * Initialise VFS inode by reading inode from inode table (compressed
0098  * metadata).  The format and amount of data read depends on type.
0099  */
0100 int squashfs_read_inode(struct inode *inode, long long ino)
0101 {
0102     struct super_block *sb = inode->i_sb;
0103     struct squashfs_sb_info *msblk = sb->s_fs_info;
0104     u64 block = SQUASHFS_INODE_BLK(ino) + msblk->inode_table;
0105     int err, type, offset = SQUASHFS_INODE_OFFSET(ino);
0106     union squashfs_inode squashfs_ino;
0107     struct squashfs_base_inode *sqshb_ino = &squashfs_ino.base;
0108     int xattr_id = SQUASHFS_INVALID_XATTR;
0109
0110     TRACE("Entered squashfs_read_inode\n");
0111
0112     /*
0113      * Read inode base common to all inode types.
0114      */
0115     err = squashfs_read_metadata(sb, sqshb_ino, &block,
0116                 &offset, sizeof(*sqshb_ino));
0117     if (err < 0)
0118         goto failed_read;
0119
0120     err = squashfs_new_inode(sb, inode, sqshb_ino);
0121     if (err)
0122         goto failed_read;
0123
0124     block = SQUASHFS_INODE_BLK(ino) + msblk->inode_table;
0125     offset = SQUASHFS_INODE_OFFSET(ino);
0126
0127     type = le16_to_cpu(sqshb_ino->inode_type);
0128     switch (type) {
0129     case SQUASHFS_REG_TYPE: {
0130         unsigned int frag_offset, frag;
0131         int frag_size;
0132         u64 frag_blk;
0133         struct squashfs_reg_inode *sqsh_ino = &squashfs_ino.reg;
0134
0135         err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
0136                             sizeof(*sqsh_ino));
0137         if (err < 0)
0138             goto failed_read;
0139
0140         frag = le32_to_cpu(sqsh_ino->fragment);
0141         if (frag != SQUASHFS_INVALID_FRAG) {
0142             frag_offset = le32_to_cpu(sqsh_ino->offset);
0143             frag_size = squashfs_frag_lookup(sb, frag, &frag_blk);
0144             if (frag_size < 0) {
0145                 err = frag_size;
0146                 goto failed_read;
0147             }
0148         } else {
0149             frag_blk = SQUASHFS_INVALID_BLK;
0150             frag_size = 0;
0151             frag_offset = 0;
0152         }
0153
0154         set_nlink(inode, 1);
0155         inode->i_size = le32_to_cpu(sqsh_ino->file_size);
0156         inode->i_fop = &generic_ro_fops;
0157         inode->i_mode |= S_IFREG;
0158         inode->i_blocks = ((inode->i_size - 1) >> 9) + 1;
0159         squashfs_i(inode)->fragment_block = frag_blk;
0160         squashfs_i(inode)->fragment_size = frag_size;
0161         squashfs_i(inode)->fragment_offset = frag_offset;
0162         squashfs_i(inode)->start = le32_to_cpu(sqsh_ino->start_block);
0163         squashfs_i(inode)->block_list_start = block;
0164         squashfs_i(inode)->offset = offset;
0165         inode->i_data.a_ops = &squashfs_aops;
0166
0167         TRACE("File inode %x:%x, start_block %llx, block_list_start "
0168             "%llx, offset %x\n", SQUASHFS_INODE_BLK(ino),
0169             offset, squashfs_i(inode)->start, block, offset);
0170         break;
0171     }
0172     case SQUASHFS_LREG_TYPE: {
0173         unsigned int frag_offset, frag;
0174         int frag_size;
0175         u64 frag_blk;
0176         struct squashfs_lreg_inode *sqsh_ino = &squashfs_ino.lreg;
0177
0178         err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
0179                             sizeof(*sqsh_ino));
0180         if (err < 0)
0181             goto failed_read;
0182
0183         frag = le32_to_cpu(sqsh_ino->fragment);
0184         if (frag != SQUASHFS_INVALID_FRAG) {
0185             frag_offset = le32_to_cpu(sqsh_ino->offset);
0186             frag_size = squashfs_frag_lookup(sb, frag, &frag_blk);
0187             if (frag_size < 0) {
0188                 err = frag_size;
0189                 goto failed_read;
0190             }
0191         } else {
0192             frag_blk = SQUASHFS_INVALID_BLK;
0193             frag_size = 0;
0194             frag_offset = 0;
0195         }
0196
0197         xattr_id = le32_to_cpu(sqsh_ino->xattr);
0198         set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
0199         inode->i_size = le64_to_cpu(sqsh_ino->file_size);
0200         inode->i_op = &squashfs_inode_ops;
0201         inode->i_fop = &generic_ro_fops;
0202         inode->i_mode |= S_IFREG;
0203         inode->i_blocks = (inode->i_size -
0204                 le64_to_cpu(sqsh_ino->sparse) + 511) >> 9;
0205
0206         squashfs_i(inode)->fragment_block = frag_blk;
0207         squashfs_i(inode)->fragment_size = frag_size;
0208         squashfs_i(inode)->fragment_offset = frag_offset;
0209         squashfs_i(inode)->start = le64_to_cpu(sqsh_ino->start_block);
0210         squashfs_i(inode)->block_list_start = block;
0211         squashfs_i(inode)->offset = offset;
0212         inode->i_data.a_ops = &squashfs_aops;
0213
0214         TRACE("File inode %x:%x, start_block %llx, block_list_start "
0215             "%llx, offset %x\n", SQUASHFS_INODE_BLK(ino),
0216             offset, squashfs_i(inode)->start, block, offset);
0217         break;
0218     }
0219     case SQUASHFS_DIR_TYPE: {
0220         struct squashfs_dir_inode *sqsh_ino = &squashfs_ino.dir;
0221
0222         err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
0223                 sizeof(*sqsh_ino));
0224         if (err < 0)
0225             goto failed_read;
0226
0227         set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
0228         inode->i_size = le16_to_cpu(sqsh_ino->file_size);
0229         inode->i_op = &squashfs_dir_inode_ops;
0230         inode->i_fop = &squashfs_dir_ops;
0231         inode->i_mode |= S_IFDIR;
0232         squashfs_i(inode)->start = le32_to_cpu(sqsh_ino->start_block);
0233         squashfs_i(inode)->offset = le16_to_cpu(sqsh_ino->offset);
0234         squashfs_i(inode)->dir_idx_cnt = 0;
0235         squashfs_i(inode)->parent = le32_to_cpu(sqsh_ino->parent_inode);
0236
0237         TRACE("Directory inode %x:%x, start_block %llx, offset %x\n",
0238                 SQUASHFS_INODE_BLK(ino), offset,
0239                 squashfs_i(inode)->start,
0240                 le16_to_cpu(sqsh_ino->offset));
0241         break;
0242     }
0243     case SQUASHFS_LDIR_TYPE: {
0244         struct squashfs_ldir_inode *sqsh_ino = &squashfs_ino.ldir;
0245
0246         err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
0247                 sizeof(*sqsh_ino));
0248         if (err < 0)
0249             goto failed_read;
0250
0251         xattr_id = le32_to_cpu(sqsh_ino->xattr);
0252         set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
0253         inode->i_size = le32_to_cpu(sqsh_ino->file_size);
0254         inode->i_op = &squashfs_dir_inode_ops;
0255         inode->i_fop = &squashfs_dir_ops;
0256         inode->i_mode |= S_IFDIR;
0257         squashfs_i(inode)->start = le32_to_cpu(sqsh_ino->start_block);
0258         squashfs_i(inode)->offset = le16_to_cpu(sqsh_ino->offset);
0259         squashfs_i(inode)->dir_idx_start = block;
0260         squashfs_i(inode)->dir_idx_offset = offset;
0261         squashfs_i(inode)->dir_idx_cnt = le16_to_cpu(sqsh_ino->i_count);
0262         squashfs_i(inode)->parent = le32_to_cpu(sqsh_ino->parent_inode);
0263
0264         TRACE("Long directory inode %x:%x, start_block %llx, offset "
0265                 "%x\n", SQUASHFS_INODE_BLK(ino), offset,
0266                 squashfs_i(inode)->start,
0267                 le16_to_cpu(sqsh_ino->offset));
0268         break;
0269     }
0270     case SQUASHFS_SYMLINK_TYPE:
0271     case SQUASHFS_LSYMLINK_TYPE: {
0272         struct squashfs_symlink_inode *sqsh_ino = &squashfs_ino.symlink;
0273
0274         err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
0275                 sizeof(*sqsh_ino));
0276         if (err < 0)
0277             goto failed_read;
0278
0279         set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
0280         inode->i_size = le32_to_cpu(sqsh_ino->symlink_size);
0281         inode->i_op = &squashfs_symlink_inode_ops;
0282         inode_nohighmem(inode);
0283         inode->i_data.a_ops = &squashfs_symlink_aops;
0284         inode->i_mode |= S_IFLNK;
0285         squashfs_i(inode)->start = block;
0286         squashfs_i(inode)->offset = offset;
0287
0288         if (type == SQUASHFS_LSYMLINK_TYPE) {
0289             __le32 xattr;
0290
0291             err = squashfs_read_metadata(sb, NULL, &block,
0292                         &offset, inode->i_size);
0293             if (err < 0)
0294                 goto failed_read;
0295             err = squashfs_read_metadata(sb, &xattr, &block,
0296                         &offset, sizeof(xattr));
0297             if (err < 0)
0298                 goto failed_read;
0299             xattr_id = le32_to_cpu(xattr);
0300         }
0301
0302         TRACE("Symbolic link inode %x:%x, start_block %llx, offset "
0303                 "%x\n", SQUASHFS_INODE_BLK(ino), offset,
0304                 block, offset);
0305         break;
0306     }
0307     case SQUASHFS_BLKDEV_TYPE:
0308     case SQUASHFS_CHRDEV_TYPE: {
0309         struct squashfs_dev_inode *sqsh_ino = &squashfs_ino.dev;
0310         unsigned int rdev;
0311
0312         err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
0313                 sizeof(*sqsh_ino));
0314         if (err < 0)
0315             goto failed_read;
0316
0317         if (type == SQUASHFS_CHRDEV_TYPE)
0318             inode->i_mode |= S_IFCHR;
0319         else
0320             inode->i_mode |= S_IFBLK;
0321         set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
0322         rdev = le32_to_cpu(sqsh_ino->rdev);
0323         init_special_inode(inode, inode->i_mode, new_decode_dev(rdev));
0324
0325         TRACE("Device inode %x:%x, rdev %x\n",
0326                 SQUASHFS_INODE_BLK(ino), offset, rdev);
0327         break;
0328     }
0329     case SQUASHFS_LBLKDEV_TYPE:
0330     case SQUASHFS_LCHRDEV_TYPE: {
0331         struct squashfs_ldev_inode *sqsh_ino = &squashfs_ino.ldev;
0332         unsigned int rdev;
0333
0334         err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
0335                 sizeof(*sqsh_ino));
0336         if (err < 0)
0337             goto failed_read;
0338
0339         if (type == SQUASHFS_LCHRDEV_TYPE)
0340             inode->i_mode |= S_IFCHR;
0341         else
0342             inode->i_mode |= S_IFBLK;
0343         xattr_id = le32_to_cpu(sqsh_ino->xattr);
0344         inode->i_op = &squashfs_inode_ops;
0345         set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
0346         rdev = le32_to_cpu(sqsh_ino->rdev);
0347         init_special_inode(inode, inode->i_mode, new_decode_dev(rdev));
0348
0349         TRACE("Device inode %x:%x, rdev %x\n",
0350                 SQUASHFS_INODE_BLK(ino), offset, rdev);
0351         break;
0352     }
0353     case SQUASHFS_FIFO_TYPE:
0354     case SQUASHFS_SOCKET_TYPE: {
0355         struct squashfs_ipc_inode *sqsh_ino = &squashfs_ino.ipc;
0356
0357         err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
0358                 sizeof(*sqsh_ino));
0359         if (err < 0)
0360             goto failed_read;
0361
0362         if (type == SQUASHFS_FIFO_TYPE)
0363             inode->i_mode |= S_IFIFO;
0364         else
0365             inode->i_mode |= S_IFSOCK;
0366         set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
0367         init_special_inode(inode, inode->i_mode, 0);
0368         break;
0369     }
0370     case SQUASHFS_LFIFO_TYPE:
0371     case SQUASHFS_LSOCKET_TYPE: {
0372         struct squashfs_lipc_inode *sqsh_ino = &squashfs_ino.lipc;
0373
0374         err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
0375                 sizeof(*sqsh_ino));
0376         if (err < 0)
0377             goto failed_read;
0378
0379         if (type == SQUASHFS_LFIFO_TYPE)
0380             inode->i_mode |= S_IFIFO;
0381         else
0382             inode->i_mode |= S_IFSOCK;
0383         xattr_id = le32_to_cpu(sqsh_ino->xattr);
0384         inode->i_op = &squashfs_inode_ops;
0385         set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
0386         init_special_inode(inode, inode->i_mode, 0);
0387         break;
0388     }
0389     default:
0390         ERROR("Unknown inode type %d in squashfs_iget!\n", type);
0391         return -EINVAL;
0392     }
0393
0394     if (xattr_id != SQUASHFS_INVALID_XATTR && msblk->xattr_id_table) {
0395         err = squashfs_xattr_lookup(sb, xattr_id,
0396                     &squashfs_i(inode)->xattr_count,
0397                     &squashfs_i(inode)->xattr_size,
0398                     &squashfs_i(inode)->xattr);
0399         if (err < 0)
0400             goto failed_read;
0401         inode->i_blocks += ((squashfs_i(inode)->xattr_size - 1) >> 9)
0402                 + 1;
0403     } else
0404         squashfs_i(inode)->xattr_count = 0;
0405
0406     return 0;
0407
0408 failed_read:
0409     ERROR("Unable to read inode 0x%llx\n", ino);
0410     return err;
0411 }
0412
0413
0414 const struct inode_operations squashfs_inode_ops = {
0415     .listxattr = squashfs_listxattr
0416 };
0417