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/*
* linux/fs/ext2/file.c
*
* Copyright (C) 1992, 1993, 1994, 1995
* Remy Card (card@masi.ibp.fr)
* Laboratoire MASI - Institut Blaise Pascal
* Universite Pierre et Marie Curie (Paris VI)
*
* from
*
* linux/fs/minix/file.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
*
* ext2 fs regular file handling primitives
*
* 64-bit file support on 64-bit platforms by Jakub Jelinek
* (jj@sunsite.ms.mff.cuni.cz)
*/
#include <linux/fs.h>
#include <linux/sched.h>
#define NBUF 32
#define MIN(a,b) (((a)<(b))?(a):(b))
#define MAX(a,b) (((a)>(b))?(a):(b))
static long long ext2_file_lseek(struct file *, long long, int);
#if BITS_PER_LONG < 64
static int ext2_open_file (struct inode *, struct file *);
#endif
#define EXT2_MAX_SIZE(bits) \
(((EXT2_NDIR_BLOCKS + (1LL << (bits - 2)) + \
(1LL << (bits - 2)) * (1LL << (bits - 2)) + \
(1LL << (bits - 2)) * (1LL << (bits - 2)) * (1LL << (bits - 2))) * \
(1LL << bits)) - 1)
static long long ext2_max_sizes[] = {
0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
EXT2_MAX_SIZE(10), EXT2_MAX_SIZE(11), EXT2_MAX_SIZE(12), EXT2_MAX_SIZE(13)
};
/*
* Make sure the offset never goes beyond the 32-bit mark..
*/
static long long ext2_file_lseek(
struct file *file,
long long offset,
int origin)
{
struct inode *inode = file->f_dentry->d_inode;
switch (origin) {
case 2:
offset += inode->i_size;
break;
case 1:
offset += file->f_pos;
}
if (offset<0)
return -EINVAL;
if (((unsigned long long) offset >> 32) != 0) {
if (offset > ext2_max_sizes[EXT2_BLOCK_SIZE_BITS(inode->i_sb)])
return -EINVAL;
}
if (offset != file->f_pos) {
file->f_pos = offset;
file->f_reada = 0;
file->f_version = ++event;
}
return offset;
}
static inline void remove_suid(struct inode *inode)
{
unsigned int mode;
/* set S_IGID if S_IXGRP is set, and always set S_ISUID */
mode = (inode->i_mode & S_IXGRP)*(S_ISGID/S_IXGRP) | S_ISUID;
/* was any of the uid bits set? */
mode &= inode->i_mode;
if (mode && !capable(CAP_FSETID)) {
inode->i_mode &= ~mode;
mark_inode_dirty(inode);
}
}
/*
* Write to a file (through the page cache).
*/
static ssize_t
ext2_file_write(struct file *file, const char *buf, size_t count, loff_t *ppos)
{
ssize_t retval;
retval = generic_file_write(file, buf, count,
ppos, block_write_partial_page);
if (retval > 0) {
struct inode *inode = file->f_dentry->d_inode;
remove_suid(inode);
inode->i_ctime = inode->i_mtime = CURRENT_TIME;
mark_inode_dirty(inode);
}
return retval;
}
/*
* Called when an inode is released. Note that this is different
* from ext2_file_open: open gets called at every open, but release
* gets called only when /all/ the files are closed.
*/
static int ext2_release_file (struct inode * inode, struct file * filp)
{
if (filp->f_mode & FMODE_WRITE)
ext2_discard_prealloc (inode);
return 0;
}
#if BITS_PER_LONG < 64
/*
* Called when an inode is about to be open.
* We use this to disallow opening RW large files on 32bit systems if
* the caller didn't specify O_LARGEFILE.
*/
static int ext2_open_file (struct inode * inode, struct file * filp)
{
if (inode->u.ext2_i.i_high_size && !(filp->f_flags & O_LARGEFILE))
return -EFBIG;
return 0;
}
#endif
/*
* We have mostly NULL's here: the current defaults are ok for
* the ext2 filesystem.
*/
static struct file_operations ext2_file_operations = {
ext2_file_lseek, /* lseek */
generic_file_read, /* read */
ext2_file_write, /* write */
NULL, /* readdir - bad */
NULL, /* poll - default */
ext2_ioctl, /* ioctl */
generic_file_mmap, /* mmap */
#if BITS_PER_LONG == 64
NULL, /* no special open is needed */
#else
ext2_open_file,
#endif
NULL, /* flush */
ext2_release_file, /* release */
ext2_sync_file, /* fsync */
NULL, /* fasync */
NULL, /* check_media_change */
NULL /* revalidate */
};
struct inode_operations ext2_file_inode_operations = {
&ext2_file_operations,/* default file operations */
NULL, /* create */
NULL, /* lookup */
NULL, /* link */
NULL, /* unlink */
NULL, /* symlink */
NULL, /* mkdir */
NULL, /* rmdir */
NULL, /* mknod */
NULL, /* rename */
NULL, /* readlink */
NULL, /* follow_link */
ext2_get_block, /* get_block */
block_read_full_page, /* readpage */
block_write_full_page, /* writepage */
ext2_truncate, /* truncate */
ext2_permission, /* permission */
NULL, /* revalidate */
};
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