linux/fs/fat/file.c
Arjan van de Ven 754661f143 [PATCH] mark struct inode_operations const 1
Many struct inode_operations in the kernel can be "const".  Marking them const
moves these to the .rodata section, which avoids false sharing with potential
dirty data.  In addition it'll catch accidental writes at compile time to
these shared resources.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-12 09:48:46 -08:00

319 lines
7.5 KiB
C

/*
* linux/fs/fat/file.c
*
* Written 1992,1993 by Werner Almesberger
*
* regular file handling primitives for fat-based filesystems
*/
#include <linux/capability.h>
#include <linux/module.h>
#include <linux/time.h>
#include <linux/msdos_fs.h>
#include <linux/smp_lock.h>
#include <linux/buffer_head.h>
#include <linux/writeback.h>
#include <linux/backing-dev.h>
#include <linux/blkdev.h>
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;
mutex_lock(&inode->i_mutex);
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_path.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:
mutex_unlock(&inode->i_mutex);
return err;
}
default:
return -ENOTTY; /* Inappropriate ioctl for device */
}
}
static int fat_file_release(struct inode *inode, struct file *filp)
{
if ((filp->f_mode & FMODE_WRITE) &&
MSDOS_SB(inode->i_sb)->options.flush) {
fat_flush_inodes(inode->i_sb, inode, NULL);
congestion_wait(WRITE, HZ/10);
}
return 0;
}
const struct file_operations fat_file_operations = {
.llseek = generic_file_llseek,
.read = do_sync_read,
.write = do_sync_write,
.aio_read = generic_file_aio_read,
.aio_write = generic_file_aio_write,
.mmap = generic_file_mmap,
.release = fat_file_release,
.ioctl = fat_generic_ioctl,
.fsync = file_fsync,
.sendfile = generic_file_sendfile,
};
static int fat_cont_expand(struct inode *inode, loff_t size)
{
struct address_space *mapping = inode->i_mapping;
loff_t start = inode->i_size, count = size - inode->i_size;
int err;
err = generic_cont_expand_simple(inode, size);
if (err)
goto out;
inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC;
mark_inode_dirty(inode);
if (IS_SYNC(inode))
err = sync_page_range_nolock(inode, mapping, start, count);
out:
return err;
}
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();
/*
* Expand the file. Since inode_setattr() updates ->i_size
* before calling the ->truncate(), but FAT needs to fill the
* hole before it.
*/
if (attr->ia_valid & ATTR_SIZE) {
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;
}
}
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_GPL(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;
fat_cache_inval_inode(inode);
wait = IS_DIRSYNC(inode);
i_start = free_start = MSDOS_I(inode)->i_start;
i_logstart = MSDOS_I(inode)->i_logstart;
/* First, we write the new file size. */
if (!skip) {
MSDOS_I(inode)->i_start = 0;
MSDOS_I(inode)->i_logstart = 0;
}
MSDOS_I(inode)->i_attrs |= ATTR_ARCH;
inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC;
if (wait) {
err = fat_sync_inode(inode);
if (err) {
MSDOS_I(inode)->i_start = i_start;
MSDOS_I(inode)->i_logstart = i_logstart;
return err;
}
} else
mark_inode_dirty(inode);
/* Write a new EOF, and get the remaining cluster chain for freeing. */
if (skip) {
struct fat_entry fatent;
int ret, fclus, dclus;
ret = fat_get_cluster(inode, skip - 1, &fclus, &dclus);
if (ret < 0)
return ret;
else if (ret == FAT_ENT_EOF)
return 0;
fatent_init(&fatent);
ret = fat_ent_read(inode, &fatent, dclus);
if (ret == FAT_ENT_EOF) {
fatent_brelse(&fatent);
return 0;
} else if (ret == FAT_ENT_FREE) {
fat_fs_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;
}
inode->i_blocks = skip << (MSDOS_SB(sb)->cluster_bits - 9);
/* Freeing the remained cluster chain */
return fat_free_clusters(inode, free_start);
}
void fat_truncate(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();
fat_flush_inodes(inode->i_sb, inode, NULL);
}
int fat_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
{
struct inode *inode = dentry->d_inode;
generic_fillattr(inode, stat);
stat->blksize = MSDOS_SB(inode->i_sb)->cluster_size;
return 0;
}
EXPORT_SYMBOL_GPL(fat_getattr);
const struct inode_operations fat_file_inode_operations = {
.truncate = fat_truncate,
.setattr = fat_notify_change,
.getattr = fat_getattr,
};