diff options
Diffstat (limited to 'kernel/fs/fat/file.c')
| -rw-r--r-- | kernel/fs/fat/file.c | 459 |
1 files changed, 459 insertions, 0 deletions
diff --git a/kernel/fs/fat/file.c b/kernel/fs/fat/file.c new file mode 100644 index 000000000..442d50a0e --- /dev/null +++ b/kernel/fs/fat/file.c @@ -0,0 +1,459 @@ +/* + * 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/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 = d_inode(dentry); + 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 = d_inode(dentry); + 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, +}; |