579 строки
15 KiB
C
579 строки
15 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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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/compat.h>
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#include <linux/mount.h>
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#include <linux/blkdev.h>
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#include <linux/backing-dev.h>
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#include <linux/fsnotify.h>
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#include <linux/security.h>
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#include <linux/falloc.h>
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#include "fat.h"
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static long fat_fallocate(struct file *file, int mode,
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loff_t offset, loff_t len);
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static int fat_ioctl_get_attributes(struct inode *inode, u32 __user *user_attr)
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{
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u32 attr;
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inode_lock_shared(inode);
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attr = fat_make_attrs(inode);
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inode_unlock_shared(inode);
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return put_user(attr, user_attr);
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}
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static int fat_ioctl_set_attributes(struct file *file, u32 __user *user_attr)
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{
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struct inode *inode = file_inode(file);
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struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
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int is_dir = S_ISDIR(inode->i_mode);
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u32 attr, oldattr;
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struct iattr ia;
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int err;
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err = get_user(attr, user_attr);
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if (err)
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goto out;
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err = mnt_want_write_file(file);
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if (err)
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goto out;
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inode_lock(inode);
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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_make_attrs(inode);
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/* Equivalent to a chmod() */
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ia.ia_valid = ATTR_MODE | ATTR_CTIME;
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ia.ia_ctime = current_time(inode);
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if (is_dir)
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ia.ia_mode = fat_make_mode(sbi, attr, S_IRWXUGO);
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else {
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ia.ia_mode = fat_make_mode(sbi, attr,
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S_IRUGO | S_IWUGO | (inode->i_mode & S_IXUGO));
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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 out_unlock_inode;
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}
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if (sbi->options.sys_immutable &&
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((attr | oldattr) & ATTR_SYS) &&
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!capable(CAP_LINUX_IMMUTABLE)) {
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err = -EPERM;
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goto out_unlock_inode;
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}
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/*
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* The security check is questionable... We single
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* out the RO attribute for checking by the security
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* module, just because it maps to a file mode.
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*/
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err = security_inode_setattr(file_mnt_user_ns(file),
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file->f_path.dentry, &ia);
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if (err)
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goto out_unlock_inode;
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/* This MUST be done before doing anything irreversible... */
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err = fat_setattr(file_mnt_user_ns(file), file->f_path.dentry, &ia);
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if (err)
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goto out_unlock_inode;
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fsnotify_change(file->f_path.dentry, ia.ia_valid);
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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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fat_save_attrs(inode, attr);
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mark_inode_dirty(inode);
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out_unlock_inode:
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inode_unlock(inode);
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mnt_drop_write_file(file);
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out:
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return err;
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}
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static int fat_ioctl_get_volume_id(struct inode *inode, u32 __user *user_attr)
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{
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struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
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return put_user(sbi->vol_id, user_attr);
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}
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static int fat_ioctl_fitrim(struct inode *inode, unsigned long arg)
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{
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struct super_block *sb = inode->i_sb;
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struct fstrim_range __user *user_range;
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struct fstrim_range range;
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int err;
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if (!capable(CAP_SYS_ADMIN))
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return -EPERM;
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if (!bdev_max_discard_sectors(sb->s_bdev))
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return -EOPNOTSUPP;
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user_range = (struct fstrim_range __user *)arg;
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if (copy_from_user(&range, user_range, sizeof(range)))
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return -EFAULT;
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range.minlen = max_t(unsigned int, range.minlen,
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bdev_discard_granularity(sb->s_bdev));
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err = fat_trim_fs(inode, &range);
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if (err < 0)
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return err;
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if (copy_to_user(user_range, &range, sizeof(range)))
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return -EFAULT;
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return 0;
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}
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long fat_generic_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
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{
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struct inode *inode = file_inode(filp);
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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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return fat_ioctl_get_attributes(inode, user_attr);
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case FAT_IOCTL_SET_ATTRIBUTES:
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return fat_ioctl_set_attributes(filp, user_attr);
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case FAT_IOCTL_GET_VOLUME_ID:
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return fat_ioctl_get_volume_id(inode, user_attr);
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case FITRIM:
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return fat_ioctl_fitrim(inode, arg);
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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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static int fat_file_release(struct inode *inode, struct file *filp)
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{
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if ((filp->f_mode & FMODE_WRITE) &&
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MSDOS_SB(inode->i_sb)->options.flush) {
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fat_flush_inodes(inode->i_sb, inode, NULL);
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set_current_state(TASK_UNINTERRUPTIBLE);
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io_schedule_timeout(HZ/10);
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}
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return 0;
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}
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int fat_file_fsync(struct file *filp, loff_t start, loff_t end, int datasync)
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{
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struct inode *inode = filp->f_mapping->host;
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int err;
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err = __generic_file_fsync(filp, start, end, datasync);
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if (err)
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return err;
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err = sync_mapping_buffers(MSDOS_SB(inode->i_sb)->fat_inode->i_mapping);
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if (err)
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return err;
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return blkdev_issue_flush(inode->i_sb->s_bdev);
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}
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const struct file_operations fat_file_operations = {
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.llseek = generic_file_llseek,
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.read_iter = generic_file_read_iter,
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.write_iter = generic_file_write_iter,
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.mmap = generic_file_mmap,
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.release = fat_file_release,
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.unlocked_ioctl = fat_generic_ioctl,
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.compat_ioctl = compat_ptr_ioctl,
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.fsync = fat_file_fsync,
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.splice_read = generic_file_splice_read,
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.splice_write = iter_file_splice_write,
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.fallocate = fat_fallocate,
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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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fat_truncate_time(inode, NULL, S_CTIME|S_MTIME);
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mark_inode_dirty(inode);
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if (IS_SYNC(inode)) {
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int err2;
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/*
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* Opencode syncing since we don't have a file open to use
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* standard fsync path.
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*/
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err = filemap_fdatawrite_range(mapping, start,
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start + count - 1);
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err2 = sync_mapping_buffers(mapping);
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if (!err)
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err = err2;
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err2 = write_inode_now(inode, 1);
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if (!err)
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err = err2;
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if (!err) {
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err = filemap_fdatawait_range(mapping, start,
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start + count - 1);
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}
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}
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out:
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return err;
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}
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/*
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* Preallocate space for a file. This implements fat's fallocate file
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* operation, which gets called from sys_fallocate system call. User
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* space requests len bytes at offset. If FALLOC_FL_KEEP_SIZE is set
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* we just allocate clusters without zeroing them out. Otherwise we
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* allocate and zero out clusters via an expanding truncate.
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*/
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static long fat_fallocate(struct file *file, int mode,
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loff_t offset, loff_t len)
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{
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int nr_cluster; /* Number of clusters to be allocated */
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loff_t mm_bytes; /* Number of bytes to be allocated for file */
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loff_t ondisksize; /* block aligned on-disk size in bytes*/
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struct inode *inode = file->f_mapping->host;
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struct super_block *sb = inode->i_sb;
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struct msdos_sb_info *sbi = MSDOS_SB(sb);
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int err = 0;
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/* No support for hole punch or other fallocate flags. */
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if (mode & ~FALLOC_FL_KEEP_SIZE)
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return -EOPNOTSUPP;
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/* No support for dir */
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if (!S_ISREG(inode->i_mode))
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return -EOPNOTSUPP;
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inode_lock(inode);
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if (mode & FALLOC_FL_KEEP_SIZE) {
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ondisksize = inode->i_blocks << 9;
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if ((offset + len) <= ondisksize)
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goto error;
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/* First compute the number of clusters to be allocated */
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mm_bytes = offset + len - ondisksize;
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nr_cluster = (mm_bytes + (sbi->cluster_size - 1)) >>
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sbi->cluster_bits;
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/* Start the allocation.We are not zeroing out the clusters */
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while (nr_cluster-- > 0) {
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err = fat_add_cluster(inode);
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if (err)
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goto error;
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}
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} else {
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if ((offset + len) <= i_size_read(inode))
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goto error;
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/* This is just an expanding truncate */
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err = fat_cont_expand(inode, (offset + len));
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}
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error:
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inode_unlock(inode);
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return err;
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}
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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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fat_truncate_time(inode, NULL, S_CTIME|S_MTIME);
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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_error(sb,
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"%s: invalid cluster chain (i_pos %lld)",
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__func__, 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_blocks(struct inode *inode, loff_t offset)
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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 > offset)
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MSDOS_I(inode)->mmu_private = offset;
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nr_clusters = (offset + (cluster_size - 1)) >> sbi->cluster_bits;
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fat_free(inode, nr_clusters);
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fat_flush_inodes(inode->i_sb, inode, NULL);
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}
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int fat_getattr(struct user_namespace *mnt_userns, const struct path *path,
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struct kstat *stat, u32 request_mask, unsigned int flags)
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{
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struct inode *inode = d_inode(path->dentry);
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struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
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generic_fillattr(mnt_userns, inode, stat);
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stat->blksize = sbi->cluster_size;
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if (sbi->options.nfs == FAT_NFS_NOSTALE_RO) {
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/* Use i_pos for ino. This is used as fileid of nfs. */
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stat->ino = fat_i_pos_read(sbi, inode);
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}
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if (sbi->options.isvfat && request_mask & STATX_BTIME) {
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stat->result_mask |= STATX_BTIME;
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stat->btime = MSDOS_I(inode)->i_crtime;
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}
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return 0;
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}
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EXPORT_SYMBOL_GPL(fat_getattr);
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static int fat_sanitize_mode(const struct msdos_sb_info *sbi,
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struct inode *inode, umode_t *mode_ptr)
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{
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umode_t mask, perm;
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/*
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* Note, the basic check is already done by a caller of
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* (attr->ia_mode & ~FAT_VALID_MODE)
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*/
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if (S_ISREG(inode->i_mode))
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mask = sbi->options.fs_fmask;
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else
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mask = sbi->options.fs_dmask;
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perm = *mode_ptr & ~(S_IFMT | mask);
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/*
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* Of the r and x bits, all (subject to umask) must be present. Of the
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* w bits, either all (subject to umask) or none must be present.
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*
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* If fat_mode_can_hold_ro(inode) is false, can't change w bits.
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*/
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if ((perm & (S_IRUGO | S_IXUGO)) != (inode->i_mode & (S_IRUGO|S_IXUGO)))
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return -EPERM;
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if (fat_mode_can_hold_ro(inode)) {
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if ((perm & S_IWUGO) && ((perm & S_IWUGO) != (S_IWUGO & ~mask)))
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return -EPERM;
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} else {
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if ((perm & S_IWUGO) != (S_IWUGO & ~mask))
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return -EPERM;
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}
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*mode_ptr &= S_IFMT | perm;
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return 0;
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}
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static int fat_allow_set_time(struct user_namespace *mnt_userns,
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struct msdos_sb_info *sbi, struct inode *inode)
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{
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umode_t allow_utime = sbi->options.allow_utime;
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if (!vfsuid_eq_kuid(i_uid_into_vfsuid(mnt_userns, inode),
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current_fsuid())) {
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if (vfsgid_in_group_p(i_gid_into_vfsgid(mnt_userns, inode)))
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allow_utime >>= 3;
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if (allow_utime & MAY_WRITE)
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return 1;
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}
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/* use a default check */
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return 0;
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}
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#define TIMES_SET_FLAGS (ATTR_MTIME_SET | ATTR_ATIME_SET | ATTR_TIMES_SET)
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/* valid file mode bits */
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#define FAT_VALID_MODE (S_IFREG | S_IFDIR | S_IRWXUGO)
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int fat_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
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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 = d_inode(dentry);
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unsigned int ia_valid;
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int error;
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/* Check for setting the inode time. */
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ia_valid = attr->ia_valid;
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if (ia_valid & TIMES_SET_FLAGS) {
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if (fat_allow_set_time(mnt_userns, sbi, inode))
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attr->ia_valid &= ~TIMES_SET_FLAGS;
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}
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error = setattr_prepare(mnt_userns, dentry, attr);
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attr->ia_valid = ia_valid;
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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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|
|
|
/*
|
|
* 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(from_vfsuid(mnt_userns, i_user_ns(inode), attr->ia_vfsuid),
|
|
sbi->options.fs_uid))) ||
|
|
((attr->ia_valid & ATTR_GID) &&
|
|
(!gid_eq(from_vfsgid(mnt_userns, i_user_ns(inode), attr->ia_vfsgid),
|
|
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 can't truncate these appropriately, so we'll
|
|
* copy them ourselves
|
|
*/
|
|
if (attr->ia_valid & ATTR_ATIME)
|
|
fat_truncate_time(inode, &attr->ia_atime, S_ATIME);
|
|
if (attr->ia_valid & ATTR_CTIME)
|
|
fat_truncate_time(inode, &attr->ia_ctime, S_CTIME);
|
|
if (attr->ia_valid & ATTR_MTIME)
|
|
fat_truncate_time(inode, &attr->ia_mtime, S_MTIME);
|
|
attr->ia_valid &= ~(ATTR_ATIME|ATTR_CTIME|ATTR_MTIME);
|
|
|
|
setattr_copy(mnt_userns, 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,
|
|
.update_time = fat_update_time,
|
|
};
|