diff options
Diffstat (limited to 'fs/fat/file.c')
| -rw-r--r-- | fs/fat/file.c | 308 |
1 files changed, 308 insertions, 0 deletions
diff --git a/fs/fat/file.c b/fs/fat/file.c new file mode 100644 index 0000000..62ffa91 --- /dev/null +++ b/fs/fat/file.c @@ -0,0 +1,308 @@ +/* + * linux/fs/fat/file.c + * + * Written 1992,1993 by Werner Almesberger + * + * regular file handling primitives for fat-based filesystems + */ + +#include <linux/module.h> +#include <linux/time.h> +#include <linux/msdos_fs.h> +#include <linux/smp_lock.h> +#include <linux/buffer_head.h> + +static ssize_t fat_file_aio_write(struct kiocb *iocb, const char __user *buf, + size_t count, loff_t pos) +{ + struct inode *inode = iocb->ki_filp->f_dentry->d_inode; + int retval; + + retval = generic_file_aio_write(iocb, buf, count, pos); + if (retval > 0) { + inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC; + MSDOS_I(inode)->i_attrs |= ATTR_ARCH; + mark_inode_dirty(inode); +// check the locking rules +// if (IS_SYNC(inode)) +// fat_sync_inode(inode); + } + return retval; +} + +static ssize_t fat_file_writev(struct file *filp, const struct iovec *iov, + unsigned long nr_segs, loff_t *ppos) +{ + struct inode *inode = filp->f_dentry->d_inode; + int retval; + + retval = generic_file_writev(filp, iov, nr_segs, ppos); + if (retval > 0) { + inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC; + MSDOS_I(inode)->i_attrs |= ATTR_ARCH; + mark_inode_dirty(inode); + } + return retval; +} + +int fat_generic_ioctl(struct inode *inode, struct file *filp, + unsigned int cmd, unsigned long arg) +{ + struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); + u32 __user *user_attr = (u32 __user *)arg; + + switch (cmd) { + case FAT_IOCTL_GET_ATTRIBUTES: + { + u32 attr; + + if (inode->i_ino == MSDOS_ROOT_INO) + attr = ATTR_DIR; + else + attr = fat_attr(inode); + + return put_user(attr, user_attr); + } + case FAT_IOCTL_SET_ATTRIBUTES: + { + u32 attr, oldattr; + int err, is_dir = S_ISDIR(inode->i_mode); + struct iattr ia; + + err = get_user(attr, user_attr); + if (err) + return err; + + down(&inode->i_sem); + + if (IS_RDONLY(inode)) { + err = -EROFS; + goto up; + } + + /* + * 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_attr(inode); + + /* Equivalent to a chmod() */ + ia.ia_valid = ATTR_MODE | ATTR_CTIME; + if (is_dir) { + ia.ia_mode = MSDOS_MKMODE(attr, + S_IRWXUGO & ~sbi->options.fs_dmask) + | S_IFDIR; + } else { + ia.ia_mode = MSDOS_MKMODE(attr, + (S_IRUGO | S_IWUGO | (inode->i_mode & S_IXUGO)) + & ~sbi->options.fs_fmask) + | S_IFREG; + } + + /* The root directory has no attributes */ + if (inode->i_ino == MSDOS_ROOT_INO && attr != ATTR_DIR) { + err = -EINVAL; + goto up; + } + + if (sbi->options.sys_immutable) { + if ((attr | oldattr) & ATTR_SYS) { + if (!capable(CAP_LINUX_IMMUTABLE)) { + err = -EPERM; + goto up; + } + } + } + + /* This MUST be done before doing anything irreversible... */ + err = notify_change(filp->f_dentry, &ia); + if (err) + goto up; + + if (sbi->options.sys_immutable) { + if (attr & ATTR_SYS) + inode->i_flags |= S_IMMUTABLE; + else + inode->i_flags &= S_IMMUTABLE; + } + + MSDOS_I(inode)->i_attrs = attr & ATTR_UNUSED; + mark_inode_dirty(inode); + up: + up(&inode->i_sem); + return err; + } + default: + return -ENOTTY; /* Inappropriate ioctl for device */ + } +} + +struct file_operations fat_file_operations = { + .llseek = generic_file_llseek, + .read = do_sync_read, + .write = do_sync_write, + .readv = generic_file_readv, + .writev = fat_file_writev, + .aio_read = generic_file_aio_read, + .aio_write = fat_file_aio_write, + .mmap = generic_file_mmap, + .ioctl = fat_generic_ioctl, + .fsync = file_fsync, + .sendfile = generic_file_sendfile, +}; + +int fat_notify_change(struct dentry *dentry, struct iattr *attr) +{ + struct msdos_sb_info *sbi = MSDOS_SB(dentry->d_sb); + struct inode *inode = dentry->d_inode; + int mask, error = 0; + + lock_kernel(); + + /* FAT cannot truncate to a longer file */ + if (attr->ia_valid & ATTR_SIZE) { + if (attr->ia_size > inode->i_size) { + error = -EPERM; + goto out; + } + } + + error = inode_change_ok(inode, attr); + if (error) { + if (sbi->options.quiet) + error = 0; + goto out; + } + if (((attr->ia_valid & ATTR_UID) && + (attr->ia_uid != sbi->options.fs_uid)) || + ((attr->ia_valid & ATTR_GID) && + (attr->ia_gid != sbi->options.fs_gid)) || + ((attr->ia_valid & ATTR_MODE) && + (attr->ia_mode & ~MSDOS_VALID_MODE))) + error = -EPERM; + + if (error) { + if (sbi->options.quiet) + error = 0; + goto out; + } + error = inode_setattr(inode, attr); + if (error) + goto out; + + if (S_ISDIR(inode->i_mode)) + mask = sbi->options.fs_dmask; + else + mask = sbi->options.fs_fmask; + inode->i_mode &= S_IFMT | (S_IRWXUGO & ~mask); +out: + unlock_kernel(); + return error; +} + +EXPORT_SYMBOL(fat_notify_change); + +/* 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; + + /* + * Write a new EOF, and get the remaining cluster chain for freeing. + */ + wait = IS_DIRSYNC(inode); + 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_panic(sb, + "%s: invalid cluster chain (i_pos %lld)", + __FUNCTION__, 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; + i_start = i_logstart = 0; + fat_cache_inval_inode(inode); + } else { + fat_cache_inval_inode(inode); + + i_start = free_start = MSDOS_I(inode)->i_start; + i_logstart = MSDOS_I(inode)->i_logstart; + 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) + goto error; + } else + mark_inode_dirty(inode); + inode->i_blocks = skip << (MSDOS_SB(sb)->cluster_bits - 9); + + /* Freeing the remained cluster chain */ + return fat_free_clusters(inode, free_start); + +error: + if (i_start) { + MSDOS_I(inode)->i_start = i_start; + MSDOS_I(inode)->i_logstart = i_logstart; + } + return err; +} + +void fat_truncate(struct inode *inode) +{ + 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 > inode->i_size) + MSDOS_I(inode)->mmu_private = inode->i_size; + + nr_clusters = (inode->i_size + (cluster_size - 1)) >> sbi->cluster_bits; + + lock_kernel(); + fat_free(inode, nr_clusters); + unlock_kernel(); +} + +struct inode_operations fat_file_inode_operations = { + .truncate = fat_truncate, + .setattr = fat_notify_change, +}; |
