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![Jan Kara](/assets/img/avatar_default.png)
When mnt_want_write() starts to handle freezing it will get a full lock semantics requiring proper lock ordering. So push mnt_want_write() call outside of i_mutex as in other places. CC: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
449 lines
11 KiB
C
449 lines
11 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/compat.h>
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#include <linux/mount.h>
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#include <linux/time.h>
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#include <linux/buffer_head.h>
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#include <linux/writeback.h>
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#include <linux/backing-dev.h>
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#include <linux/blkdev.h>
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#include <linux/fsnotify.h>
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#include <linux/security.h>
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#include "fat.h"
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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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mutex_lock(&inode->i_mutex);
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attr = fat_make_attrs(inode);
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mutex_unlock(&inode->i_mutex);
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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->f_path.dentry->d_inode;
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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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mutex_lock(&inode->i_mutex);
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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_fs_time(inode->i_sb);
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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->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->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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mutex_unlock(&inode->i_mutex);
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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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long fat_generic_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
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{
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struct inode *inode = filp->f_path.dentry->d_inode;
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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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default:
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return -ENOTTY; /* Inappropriate ioctl for device */
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}
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}
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#ifdef CONFIG_COMPAT
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static long fat_generic_compat_ioctl(struct file *filp, unsigned int cmd,
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unsigned long arg)
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{
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return fat_generic_ioctl(filp, cmd, (unsigned long)compat_ptr(arg));
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}
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#endif
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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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congestion_wait(BLK_RW_ASYNC, 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 res, err;
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res = generic_file_fsync(filp, start, end, datasync);
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err = sync_mapping_buffers(MSDOS_SB(inode->i_sb)->fat_inode->i_mapping);
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return res ? res : err;
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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 = do_sync_read,
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.write = do_sync_write,
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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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.release = fat_file_release,
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.unlocked_ioctl = fat_generic_ioctl,
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#ifdef CONFIG_COMPAT
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.compat_ioctl = fat_generic_compat_ioctl,
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#endif
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.fsync = fat_file_fsync,
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.splice_read = generic_file_splice_read,
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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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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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/* 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_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 vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
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{
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struct inode *inode = dentry->d_inode;
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generic_fillattr(inode, stat);
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stat->blksize = MSDOS_SB(inode->i_sb)->cluster_size;
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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 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 (current_fsuid() != inode->i_uid) {
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if (in_group_p(inode->i_gid))
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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 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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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(sbi, inode))
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attr->ia_valid &= ~TIMES_SET_FLAGS;
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}
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error = inode_change_ok(inode, 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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/*
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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. XXX: this is no longer true with new truncate
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* sequence.
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*/
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if (attr->ia_valid & ATTR_SIZE) {
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inode_dio_wait(inode);
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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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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 & ~FAT_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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/*
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* We don't return -EPERM here. Yes, strange, but this is too
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* old behavior.
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*/
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if (attr->ia_valid & ATTR_MODE) {
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if (fat_sanitize_mode(sbi, inode, &attr->ia_mode) < 0)
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attr->ia_valid &= ~ATTR_MODE;
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}
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if (attr->ia_valid & ATTR_SIZE) {
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down_write(&MSDOS_I(inode)->truncate_lock);
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truncate_setsize(inode, attr->ia_size);
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fat_truncate_blocks(inode, attr->ia_size);
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up_write(&MSDOS_I(inode)->truncate_lock);
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}
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setattr_copy(inode, attr);
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mark_inode_dirty(inode);
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out:
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return error;
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}
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EXPORT_SYMBOL_GPL(fat_setattr);
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const struct inode_operations fat_file_inode_operations = {
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.setattr = fat_setattr,
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.getattr = fat_getattr,
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};
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