298 строки
6.9 KiB
C
298 строки
6.9 KiB
C
/*
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* linux/fs/fat/file.c
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*
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* Written 1992,1993 by Werner Almesberger
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*
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* regular file handling primitives for fat-based filesystems
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*/
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#include <linux/capability.h>
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#include <linux/module.h>
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#include <linux/time.h>
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#include <linux/msdos_fs.h>
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#include <linux/smp_lock.h>
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#include <linux/buffer_head.h>
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#include <linux/writeback.h>
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int fat_generic_ioctl(struct inode *inode, struct file *filp,
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unsigned int cmd, unsigned long arg)
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{
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struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
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u32 __user *user_attr = (u32 __user *)arg;
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switch (cmd) {
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case FAT_IOCTL_GET_ATTRIBUTES:
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{
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u32 attr;
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if (inode->i_ino == MSDOS_ROOT_INO)
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attr = ATTR_DIR;
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else
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attr = fat_attr(inode);
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return put_user(attr, user_attr);
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}
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case FAT_IOCTL_SET_ATTRIBUTES:
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{
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u32 attr, oldattr;
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int err, is_dir = S_ISDIR(inode->i_mode);
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struct iattr ia;
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err = get_user(attr, user_attr);
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if (err)
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return err;
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mutex_lock(&inode->i_mutex);
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if (IS_RDONLY(inode)) {
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err = -EROFS;
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goto up;
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}
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/*
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* ATTR_VOLUME and ATTR_DIR cannot be changed; this also
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* prevents the user from turning us into a VFAT
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* longname entry. Also, we obviously can't set
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* any of the NTFS attributes in the high 24 bits.
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*/
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attr &= 0xff & ~(ATTR_VOLUME | ATTR_DIR);
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/* Merge in ATTR_VOLUME and ATTR_DIR */
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attr |= (MSDOS_I(inode)->i_attrs & ATTR_VOLUME) |
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(is_dir ? ATTR_DIR : 0);
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oldattr = fat_attr(inode);
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/* Equivalent to a chmod() */
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ia.ia_valid = ATTR_MODE | ATTR_CTIME;
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if (is_dir) {
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ia.ia_mode = MSDOS_MKMODE(attr,
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S_IRWXUGO & ~sbi->options.fs_dmask)
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| S_IFDIR;
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} else {
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ia.ia_mode = MSDOS_MKMODE(attr,
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(S_IRUGO | S_IWUGO | (inode->i_mode & S_IXUGO))
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& ~sbi->options.fs_fmask)
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| S_IFREG;
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}
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/* The root directory has no attributes */
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if (inode->i_ino == MSDOS_ROOT_INO && attr != ATTR_DIR) {
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err = -EINVAL;
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goto up;
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}
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if (sbi->options.sys_immutable) {
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if ((attr | oldattr) & ATTR_SYS) {
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if (!capable(CAP_LINUX_IMMUTABLE)) {
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err = -EPERM;
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goto up;
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}
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}
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}
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/* This MUST be done before doing anything irreversible... */
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err = notify_change(filp->f_dentry, &ia);
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if (err)
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goto up;
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if (sbi->options.sys_immutable) {
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if (attr & ATTR_SYS)
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inode->i_flags |= S_IMMUTABLE;
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else
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inode->i_flags &= S_IMMUTABLE;
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}
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MSDOS_I(inode)->i_attrs = attr & ATTR_UNUSED;
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mark_inode_dirty(inode);
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up:
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mutex_unlock(&inode->i_mutex);
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return err;
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}
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default:
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return -ENOTTY; /* Inappropriate ioctl for device */
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}
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}
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struct file_operations fat_file_operations = {
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.llseek = generic_file_llseek,
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.read = do_sync_read,
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.write = do_sync_write,
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.readv = generic_file_readv,
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.writev = generic_file_writev,
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.aio_read = generic_file_aio_read,
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.aio_write = generic_file_aio_write,
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.mmap = generic_file_mmap,
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.ioctl = fat_generic_ioctl,
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.fsync = file_fsync,
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.sendfile = generic_file_sendfile,
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};
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static int fat_cont_expand(struct inode *inode, loff_t size)
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{
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struct address_space *mapping = inode->i_mapping;
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loff_t start = inode->i_size, count = size - inode->i_size;
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int err;
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err = generic_cont_expand_simple(inode, size);
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if (err)
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goto out;
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inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC;
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mark_inode_dirty(inode);
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if (IS_SYNC(inode))
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err = sync_page_range_nolock(inode, mapping, start, count);
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out:
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return err;
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}
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int fat_notify_change(struct dentry *dentry, struct iattr *attr)
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{
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struct msdos_sb_info *sbi = MSDOS_SB(dentry->d_sb);
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struct inode *inode = dentry->d_inode;
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int mask, error = 0;
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lock_kernel();
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/*
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* Expand the file. Since inode_setattr() updates ->i_size
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* before calling the ->truncate(), but FAT needs to fill the
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* hole before it.
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*/
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if (attr->ia_valid & ATTR_SIZE) {
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if (attr->ia_size > inode->i_size) {
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error = fat_cont_expand(inode, attr->ia_size);
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if (error || attr->ia_valid == ATTR_SIZE)
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goto out;
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attr->ia_valid &= ~ATTR_SIZE;
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}
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}
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error = inode_change_ok(inode, attr);
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if (error) {
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if (sbi->options.quiet)
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error = 0;
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goto out;
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}
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if (((attr->ia_valid & ATTR_UID) &&
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(attr->ia_uid != sbi->options.fs_uid)) ||
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((attr->ia_valid & ATTR_GID) &&
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(attr->ia_gid != sbi->options.fs_gid)) ||
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((attr->ia_valid & ATTR_MODE) &&
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(attr->ia_mode & ~MSDOS_VALID_MODE)))
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error = -EPERM;
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if (error) {
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if (sbi->options.quiet)
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error = 0;
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goto out;
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}
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error = inode_setattr(inode, attr);
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if (error)
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goto out;
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if (S_ISDIR(inode->i_mode))
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mask = sbi->options.fs_dmask;
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else
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mask = sbi->options.fs_fmask;
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inode->i_mode &= S_IFMT | (S_IRWXUGO & ~mask);
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out:
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unlock_kernel();
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return error;
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}
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EXPORT_SYMBOL_GPL(fat_notify_change);
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/* Free all clusters after the skip'th cluster. */
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static int fat_free(struct inode *inode, int skip)
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{
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struct super_block *sb = inode->i_sb;
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int err, wait, free_start, i_start, i_logstart;
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if (MSDOS_I(inode)->i_start == 0)
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return 0;
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fat_cache_inval_inode(inode);
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wait = IS_DIRSYNC(inode);
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i_start = free_start = MSDOS_I(inode)->i_start;
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i_logstart = MSDOS_I(inode)->i_logstart;
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/* First, we write the new file size. */
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if (!skip) {
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MSDOS_I(inode)->i_start = 0;
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MSDOS_I(inode)->i_logstart = 0;
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}
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MSDOS_I(inode)->i_attrs |= ATTR_ARCH;
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inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC;
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if (wait) {
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err = fat_sync_inode(inode);
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if (err) {
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MSDOS_I(inode)->i_start = i_start;
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MSDOS_I(inode)->i_logstart = i_logstart;
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return err;
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}
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} else
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mark_inode_dirty(inode);
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/* Write a new EOF, and get the remaining cluster chain for freeing. */
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if (skip) {
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struct fat_entry fatent;
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int ret, fclus, dclus;
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ret = fat_get_cluster(inode, skip - 1, &fclus, &dclus);
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if (ret < 0)
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return ret;
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else if (ret == FAT_ENT_EOF)
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return 0;
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fatent_init(&fatent);
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ret = fat_ent_read(inode, &fatent, dclus);
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if (ret == FAT_ENT_EOF) {
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fatent_brelse(&fatent);
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return 0;
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} else if (ret == FAT_ENT_FREE) {
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fat_fs_panic(sb,
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"%s: invalid cluster chain (i_pos %lld)",
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__FUNCTION__, MSDOS_I(inode)->i_pos);
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ret = -EIO;
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} else if (ret > 0) {
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err = fat_ent_write(inode, &fatent, FAT_ENT_EOF, wait);
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if (err)
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ret = err;
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}
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fatent_brelse(&fatent);
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if (ret < 0)
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return ret;
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free_start = ret;
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}
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inode->i_blocks = skip << (MSDOS_SB(sb)->cluster_bits - 9);
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/* Freeing the remained cluster chain */
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return fat_free_clusters(inode, free_start);
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}
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void fat_truncate(struct inode *inode)
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{
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struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
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const unsigned int cluster_size = sbi->cluster_size;
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int nr_clusters;
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/*
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* This protects against truncating a file bigger than it was then
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* trying to write into the hole.
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*/
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if (MSDOS_I(inode)->mmu_private > inode->i_size)
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MSDOS_I(inode)->mmu_private = inode->i_size;
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nr_clusters = (inode->i_size + (cluster_size - 1)) >> sbi->cluster_bits;
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lock_kernel();
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fat_free(inode, nr_clusters);
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unlock_kernel();
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}
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struct inode_operations fat_file_inode_operations = {
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.truncate = fat_truncate,
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.setattr = fat_notify_change,
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};
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