| /* |
| * linux/fs/fat/file.c |
| * |
| * Written 1992,1993 by Werner Almesberger |
| * |
| * regular file handling primitives for fat-based filesystems |
| */ |
| |
| #include <linux/capability.h> |
| #include <linux/module.h> |
| #include <linux/compat.h> |
| #include <linux/mount.h> |
| #include <linux/time.h> |
| #include <linux/buffer_head.h> |
| #include <linux/writeback.h> |
| #include <linux/backing-dev.h> |
| #include <linux/blkdev.h> |
| #include <linux/fsnotify.h> |
| #include <linux/security.h> |
| #include "fat.h" |
| |
| static int fat_ioctl_get_attributes(struct inode *inode, u32 __user *user_attr) |
| { |
| u32 attr; |
| |
| mutex_lock(&inode->i_mutex); |
| attr = fat_make_attrs(inode); |
| mutex_unlock(&inode->i_mutex); |
| |
| return put_user(attr, user_attr); |
| } |
| |
| static int fat_ioctl_set_attributes(struct file *file, u32 __user *user_attr) |
| { |
| struct inode *inode = file_inode(file); |
| struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); |
| int is_dir = S_ISDIR(inode->i_mode); |
| u32 attr, oldattr; |
| struct iattr ia; |
| int err; |
| |
| err = get_user(attr, user_attr); |
| if (err) |
| goto out; |
| |
| err = mnt_want_write_file(file); |
| if (err) |
| goto out; |
| mutex_lock(&inode->i_mutex); |
| |
| /* |
| * ATTR_VOLUME and ATTR_DIR cannot be changed; this also |
| * prevents the user from turning us into a VFAT |
| * longname entry. Also, we obviously can't set |
| * any of the NTFS attributes in the high 24 bits. |
| */ |
| attr &= 0xff & ~(ATTR_VOLUME | ATTR_DIR); |
| /* Merge in ATTR_VOLUME and ATTR_DIR */ |
| attr |= (MSDOS_I(inode)->i_attrs & ATTR_VOLUME) | |
| (is_dir ? ATTR_DIR : 0); |
| oldattr = fat_make_attrs(inode); |
| |
| /* Equivalent to a chmod() */ |
| ia.ia_valid = ATTR_MODE | ATTR_CTIME; |
| ia.ia_ctime = current_fs_time(inode->i_sb); |
| if (is_dir) |
| ia.ia_mode = fat_make_mode(sbi, attr, S_IRWXUGO); |
| else { |
| ia.ia_mode = fat_make_mode(sbi, attr, |
| S_IRUGO | S_IWUGO | (inode->i_mode & S_IXUGO)); |
| } |
| |
| /* The root directory has no attributes */ |
| if (inode->i_ino == MSDOS_ROOT_INO && attr != ATTR_DIR) { |
| err = -EINVAL; |
| goto out_unlock_inode; |
| } |
| |
| if (sbi->options.sys_immutable && |
| ((attr | oldattr) & ATTR_SYS) && |
| !capable(CAP_LINUX_IMMUTABLE)) { |
| err = -EPERM; |
| goto out_unlock_inode; |
| } |
| |
| /* |
| * The security check is questionable... We single |
| * out the RO attribute for checking by the security |
| * module, just because it maps to a file mode. |
| */ |
| err = security_inode_setattr(file->f_path.dentry, &ia); |
| if (err) |
| goto out_unlock_inode; |
| |
| /* This MUST be done before doing anything irreversible... */ |
| err = fat_setattr(file->f_path.dentry, &ia); |
| if (err) |
| goto out_unlock_inode; |
| |
| fsnotify_change(file->f_path.dentry, ia.ia_valid); |
| if (sbi->options.sys_immutable) { |
| if (attr & ATTR_SYS) |
| inode->i_flags |= S_IMMUTABLE; |
| else |
| inode->i_flags &= ~S_IMMUTABLE; |
| } |
| |
| fat_save_attrs(inode, attr); |
| mark_inode_dirty(inode); |
| out_unlock_inode: |
| mutex_unlock(&inode->i_mutex); |
| mnt_drop_write_file(file); |
| out: |
| return err; |
| } |
| |
| static int fat_ioctl_get_volume_id(struct inode *inode, u32 __user *user_attr) |
| { |
| struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); |
| return put_user(sbi->vol_id, user_attr); |
| } |
| |
| long fat_generic_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) |
| { |
| struct inode *inode = file_inode(filp); |
| u32 __user *user_attr = (u32 __user *)arg; |
| |
| switch (cmd) { |
| case FAT_IOCTL_GET_ATTRIBUTES: |
| return fat_ioctl_get_attributes(inode, user_attr); |
| case FAT_IOCTL_SET_ATTRIBUTES: |
| return fat_ioctl_set_attributes(filp, user_attr); |
| case FAT_IOCTL_GET_VOLUME_ID: |
| return fat_ioctl_get_volume_id(inode, user_attr); |
| default: |
| return -ENOTTY; /* Inappropriate ioctl for device */ |
| } |
| } |
| |
| #ifdef CONFIG_COMPAT |
| static long fat_generic_compat_ioctl(struct file *filp, unsigned int cmd, |
| unsigned long arg) |
| |
| { |
| return fat_generic_ioctl(filp, cmd, (unsigned long)compat_ptr(arg)); |
| } |
| #endif |
| |
| static int fat_file_release(struct inode *inode, struct file *filp) |
| { |
| if ((filp->f_mode & FMODE_WRITE) && |
| MSDOS_SB(inode->i_sb)->options.flush) { |
| fat_flush_inodes(inode->i_sb, inode, NULL); |
| congestion_wait(BLK_RW_ASYNC, HZ/10); |
| } |
| return 0; |
| } |
| |
| int fat_file_fsync(struct file *filp, loff_t start, loff_t end, int datasync) |
| { |
| struct inode *inode = filp->f_mapping->host; |
| int res, err; |
| |
| res = generic_file_fsync(filp, start, end, datasync); |
| err = sync_mapping_buffers(MSDOS_SB(inode->i_sb)->fat_inode->i_mapping); |
| |
| return res ? res : err; |
| } |
| |
| |
| const struct file_operations fat_file_operations = { |
| .llseek = generic_file_llseek, |
| .read_iter = generic_file_read_iter, |
| .write_iter = generic_file_write_iter, |
| .mmap = generic_file_mmap, |
| .release = fat_file_release, |
| .unlocked_ioctl = fat_generic_ioctl, |
| #ifdef CONFIG_COMPAT |
| .compat_ioctl = fat_generic_compat_ioctl, |
| #endif |
| .fsync = fat_file_fsync, |
| .splice_read = generic_file_splice_read, |
| }; |
| |
| static int fat_cont_expand(struct inode *inode, loff_t size) |
| { |
| struct address_space *mapping = inode->i_mapping; |
| loff_t start = inode->i_size, count = size - inode->i_size; |
| int err; |
| |
| err = generic_cont_expand_simple(inode, size); |
| if (err) |
| goto out; |
| |
| inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC; |
| mark_inode_dirty(inode); |
| if (IS_SYNC(inode)) { |
| int err2; |
| |
| /* |
| * Opencode syncing since we don't have a file open to use |
| * standard fsync path. |
| */ |
| err = filemap_fdatawrite_range(mapping, start, |
| start + count - 1); |
| err2 = sync_mapping_buffers(mapping); |
| if (!err) |
| err = err2; |
| err2 = write_inode_now(inode, 1); |
| if (!err) |
| err = err2; |
| if (!err) { |
| err = filemap_fdatawait_range(mapping, start, |
| start + count - 1); |
| } |
| } |
| out: |
| return err; |
| } |
| |
| /* Free all clusters after the skip'th cluster. */ |
| static int fat_free(struct inode *inode, int skip) |
| { |
| struct super_block *sb = inode->i_sb; |
| int err, wait, free_start, i_start, i_logstart; |
| |
| if (MSDOS_I(inode)->i_start == 0) |
| return 0; |
| |
| fat_cache_inval_inode(inode); |
| |
| wait = IS_DIRSYNC(inode); |
| i_start = free_start = MSDOS_I(inode)->i_start; |
| i_logstart = MSDOS_I(inode)->i_logstart; |
| |
| /* First, we write the new file size. */ |
| if (!skip) { |
| MSDOS_I(inode)->i_start = 0; |
| MSDOS_I(inode)->i_logstart = 0; |
| } |
| MSDOS_I(inode)->i_attrs |= ATTR_ARCH; |
| inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC; |
| if (wait) { |
| err = fat_sync_inode(inode); |
| if (err) { |
| MSDOS_I(inode)->i_start = i_start; |
| MSDOS_I(inode)->i_logstart = i_logstart; |
| return err; |
| } |
| } else |
| mark_inode_dirty(inode); |
| |
| /* Write a new EOF, and get the remaining cluster chain for freeing. */ |
| if (skip) { |
| struct fat_entry fatent; |
| int ret, fclus, dclus; |
| |
| ret = fat_get_cluster(inode, skip - 1, &fclus, &dclus); |
| if (ret < 0) |
| return ret; |
| else if (ret == FAT_ENT_EOF) |
| return 0; |
| |
| fatent_init(&fatent); |
| ret = fat_ent_read(inode, &fatent, dclus); |
| if (ret == FAT_ENT_EOF) { |
| fatent_brelse(&fatent); |
| return 0; |
| } else if (ret == FAT_ENT_FREE) { |
| fat_fs_error(sb, |
| "%s: invalid cluster chain (i_pos %lld)", |
| __func__, MSDOS_I(inode)->i_pos); |
| ret = -EIO; |
| } else if (ret > 0) { |
| err = fat_ent_write(inode, &fatent, FAT_ENT_EOF, wait); |
| if (err) |
| ret = err; |
| } |
| fatent_brelse(&fatent); |
| if (ret < 0) |
| return ret; |
| |
| free_start = ret; |
| } |
| inode->i_blocks = skip << (MSDOS_SB(sb)->cluster_bits - 9); |
| |
| /* Freeing the remained cluster chain */ |
| return fat_free_clusters(inode, free_start); |
| } |
| |
| void fat_truncate_blocks(struct inode *inode, loff_t offset) |
| { |
| struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); |
| const unsigned int cluster_size = sbi->cluster_size; |
| int nr_clusters; |
| |
| /* |
| * This protects against truncating a file bigger than it was then |
| * trying to write into the hole. |
| */ |
| if (MSDOS_I(inode)->mmu_private > offset) |
| MSDOS_I(inode)->mmu_private = offset; |
| |
| nr_clusters = (offset + (cluster_size - 1)) >> sbi->cluster_bits; |
| |
| fat_free(inode, nr_clusters); |
| fat_flush_inodes(inode->i_sb, inode, NULL); |
| } |
| |
| int fat_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat) |
| { |
| struct inode *inode = dentry->d_inode; |
| generic_fillattr(inode, stat); |
| stat->blksize = MSDOS_SB(inode->i_sb)->cluster_size; |
| |
| if (MSDOS_SB(inode->i_sb)->options.nfs == FAT_NFS_NOSTALE_RO) { |
| /* Use i_pos for ino. This is used as fileid of nfs. */ |
| stat->ino = fat_i_pos_read(MSDOS_SB(inode->i_sb), inode); |
| } |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(fat_getattr); |
| |
| static int fat_sanitize_mode(const struct msdos_sb_info *sbi, |
| struct inode *inode, umode_t *mode_ptr) |
| { |
| umode_t mask, perm; |
| |
| /* |
| * Note, the basic check is already done by a caller of |
| * (attr->ia_mode & ~FAT_VALID_MODE) |
| */ |
| |
| if (S_ISREG(inode->i_mode)) |
| mask = sbi->options.fs_fmask; |
| else |
| mask = sbi->options.fs_dmask; |
| |
| perm = *mode_ptr & ~(S_IFMT | mask); |
| |
| /* |
| * Of the r and x bits, all (subject to umask) must be present. Of the |
| * w bits, either all (subject to umask) or none must be present. |
| * |
| * If fat_mode_can_hold_ro(inode) is false, can't change w bits. |
| */ |
| if ((perm & (S_IRUGO | S_IXUGO)) != (inode->i_mode & (S_IRUGO|S_IXUGO))) |
| return -EPERM; |
| if (fat_mode_can_hold_ro(inode)) { |
| if ((perm & S_IWUGO) && ((perm & S_IWUGO) != (S_IWUGO & ~mask))) |
| return -EPERM; |
| } else { |
| if ((perm & S_IWUGO) != (S_IWUGO & ~mask)) |
| return -EPERM; |
| } |
| |
| *mode_ptr &= S_IFMT | perm; |
| |
| return 0; |
| } |
| |
| static int fat_allow_set_time(struct msdos_sb_info *sbi, struct inode *inode) |
| { |
| umode_t allow_utime = sbi->options.allow_utime; |
| |
| if (!uid_eq(current_fsuid(), inode->i_uid)) { |
| if (in_group_p(inode->i_gid)) |
| allow_utime >>= 3; |
| if (allow_utime & MAY_WRITE) |
| return 1; |
| } |
| |
| /* use a default check */ |
| return 0; |
| } |
| |
| #define TIMES_SET_FLAGS (ATTR_MTIME_SET | ATTR_ATIME_SET | ATTR_TIMES_SET) |
| /* valid file mode bits */ |
| #define FAT_VALID_MODE (S_IFREG | S_IFDIR | S_IRWXUGO) |
| |
| int fat_setattr(struct dentry *dentry, struct iattr *attr) |
| { |
| struct msdos_sb_info *sbi = MSDOS_SB(dentry->d_sb); |
| struct inode *inode = dentry->d_inode; |
| unsigned int ia_valid; |
| int error; |
| |
| /* Check for setting the inode time. */ |
| ia_valid = attr->ia_valid; |
| if (ia_valid & TIMES_SET_FLAGS) { |
| if (fat_allow_set_time(sbi, inode)) |
| attr->ia_valid &= ~TIMES_SET_FLAGS; |
| } |
| |
| error = inode_change_ok(inode, attr); |
| attr->ia_valid = ia_valid; |
| if (error) { |
| if (sbi->options.quiet) |
| error = 0; |
| goto out; |
| } |
| |
| /* |
| * Expand the file. Since inode_setattr() updates ->i_size |
| * before calling the ->truncate(), but FAT needs to fill the |
| * hole before it. XXX: this is no longer true with new truncate |
| * sequence. |
| */ |
| if (attr->ia_valid & ATTR_SIZE) { |
| inode_dio_wait(inode); |
| |
| if (attr->ia_size > inode->i_size) { |
| error = fat_cont_expand(inode, attr->ia_size); |
| if (error || attr->ia_valid == ATTR_SIZE) |
| goto out; |
| attr->ia_valid &= ~ATTR_SIZE; |
| } |
| } |
| |
| if (((attr->ia_valid & ATTR_UID) && |
| (!uid_eq(attr->ia_uid, sbi->options.fs_uid))) || |
| ((attr->ia_valid & ATTR_GID) && |
| (!gid_eq(attr->ia_gid, sbi->options.fs_gid))) || |
| ((attr->ia_valid & ATTR_MODE) && |
| (attr->ia_mode & ~FAT_VALID_MODE))) |
| error = -EPERM; |
| |
| if (error) { |
| if (sbi->options.quiet) |
| error = 0; |
| goto out; |
| } |
| |
| /* |
| * We don't return -EPERM here. Yes, strange, but this is too |
| * old behavior. |
| */ |
| if (attr->ia_valid & ATTR_MODE) { |
| if (fat_sanitize_mode(sbi, inode, &attr->ia_mode) < 0) |
| attr->ia_valid &= ~ATTR_MODE; |
| } |
| |
| if (attr->ia_valid & ATTR_SIZE) { |
| error = fat_block_truncate_page(inode, attr->ia_size); |
| if (error) |
| goto out; |
| down_write(&MSDOS_I(inode)->truncate_lock); |
| truncate_setsize(inode, attr->ia_size); |
| fat_truncate_blocks(inode, attr->ia_size); |
| up_write(&MSDOS_I(inode)->truncate_lock); |
| } |
| |
| setattr_copy(inode, attr); |
| mark_inode_dirty(inode); |
| out: |
| return error; |
| } |
| EXPORT_SYMBOL_GPL(fat_setattr); |
| |
| const struct inode_operations fat_file_inode_operations = { |
| .setattr = fat_setattr, |
| .getattr = fat_getattr, |
| }; |