linux/fs/reiserfs/ioctl.c
Jeff Mahoney 278f6679f4 reiserfs: locking, handle nested locks properly
The reiserfs write lock replaced the BKL and uses similar semantics.

Frederic's locking code makes a distinction between when the lock is nested
and when it's being acquired/released, but I don't think that's the right
distinction to make.

The right distinction is between the lock being released at end-of-use and
the lock being released for a schedule. The unlock should return the depth
and the lock should restore it, rather than the other way around as it is now.

This patch implements that and adds a number of places where the lock
should be dropped.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
2013-08-08 17:34:46 -04:00

226 lines
5.3 KiB
C

/*
* Copyright 2000 by Hans Reiser, licensing governed by reiserfs/README
*/
#include <linux/capability.h>
#include <linux/fs.h>
#include <linux/mount.h>
#include "reiserfs.h"
#include <linux/time.h>
#include <asm/uaccess.h>
#include <linux/pagemap.h>
#include <linux/compat.h>
/*
* reiserfs_ioctl - handler for ioctl for inode
* supported commands:
* 1) REISERFS_IOC_UNPACK - try to unpack tail from direct item into indirect
* and prevent packing file (argument arg has to be non-zero)
* 2) REISERFS_IOC_[GS]ETFLAGS, REISERFS_IOC_[GS]ETVERSION
* 3) That's all for a while ...
*/
long reiserfs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{
struct inode *inode = file_inode(filp);
unsigned int flags;
int err = 0;
reiserfs_write_lock(inode->i_sb);
switch (cmd) {
case REISERFS_IOC_UNPACK:
if (S_ISREG(inode->i_mode)) {
if (arg)
err = reiserfs_unpack(inode, filp);
} else
err = -ENOTTY;
break;
/*
* following two cases are taken from fs/ext2/ioctl.c by Remy
* Card (card@masi.ibp.fr)
*/
case REISERFS_IOC_GETFLAGS:
if (!reiserfs_attrs(inode->i_sb)) {
err = -ENOTTY;
break;
}
flags = REISERFS_I(inode)->i_attrs;
i_attrs_to_sd_attrs(inode, (__u16 *) & flags);
err = put_user(flags, (int __user *)arg);
break;
case REISERFS_IOC_SETFLAGS:{
if (!reiserfs_attrs(inode->i_sb)) {
err = -ENOTTY;
break;
}
err = mnt_want_write_file(filp);
if (err)
break;
if (!inode_owner_or_capable(inode)) {
err = -EPERM;
goto setflags_out;
}
if (get_user(flags, (int __user *)arg)) {
err = -EFAULT;
goto setflags_out;
}
/*
* Is it quota file? Do not allow user to mess with it
*/
if (IS_NOQUOTA(inode)) {
err = -EPERM;
goto setflags_out;
}
if (((flags ^ REISERFS_I(inode)->
i_attrs) & (REISERFS_IMMUTABLE_FL |
REISERFS_APPEND_FL))
&& !capable(CAP_LINUX_IMMUTABLE)) {
err = -EPERM;
goto setflags_out;
}
if ((flags & REISERFS_NOTAIL_FL) &&
S_ISREG(inode->i_mode)) {
int result;
result = reiserfs_unpack(inode, filp);
if (result) {
err = result;
goto setflags_out;
}
}
sd_attrs_to_i_attrs(flags, inode);
REISERFS_I(inode)->i_attrs = flags;
inode->i_ctime = CURRENT_TIME_SEC;
mark_inode_dirty(inode);
setflags_out:
mnt_drop_write_file(filp);
break;
}
case REISERFS_IOC_GETVERSION:
err = put_user(inode->i_generation, (int __user *)arg);
break;
case REISERFS_IOC_SETVERSION:
if (!inode_owner_or_capable(inode)) {
err = -EPERM;
break;
}
err = mnt_want_write_file(filp);
if (err)
break;
if (get_user(inode->i_generation, (int __user *)arg)) {
err = -EFAULT;
goto setversion_out;
}
inode->i_ctime = CURRENT_TIME_SEC;
mark_inode_dirty(inode);
setversion_out:
mnt_drop_write_file(filp);
break;
default:
err = -ENOTTY;
}
reiserfs_write_unlock(inode->i_sb);
return err;
}
#ifdef CONFIG_COMPAT
long reiserfs_compat_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
/* These are just misnamed, they actually get/put from/to user an int */
switch (cmd) {
case REISERFS_IOC32_UNPACK:
cmd = REISERFS_IOC_UNPACK;
break;
case REISERFS_IOC32_GETFLAGS:
cmd = REISERFS_IOC_GETFLAGS;
break;
case REISERFS_IOC32_SETFLAGS:
cmd = REISERFS_IOC_SETFLAGS;
break;
case REISERFS_IOC32_GETVERSION:
cmd = REISERFS_IOC_GETVERSION;
break;
case REISERFS_IOC32_SETVERSION:
cmd = REISERFS_IOC_SETVERSION;
break;
default:
return -ENOIOCTLCMD;
}
return reiserfs_ioctl(file, cmd, (unsigned long) compat_ptr(arg));
}
#endif
int reiserfs_commit_write(struct file *f, struct page *page,
unsigned from, unsigned to);
/*
** reiserfs_unpack
** Function try to convert tail from direct item into indirect.
** It set up nopack attribute in the REISERFS_I(inode)->nopack
*/
int reiserfs_unpack(struct inode *inode, struct file *filp)
{
int retval = 0;
int index;
struct page *page;
struct address_space *mapping;
unsigned long write_from;
unsigned long blocksize = inode->i_sb->s_blocksize;
if (inode->i_size == 0) {
REISERFS_I(inode)->i_flags |= i_nopack_mask;
return 0;
}
/* ioctl already done */
if (REISERFS_I(inode)->i_flags & i_nopack_mask) {
return 0;
}
/* we need to make sure nobody is changing the file size beneath us */
reiserfs_mutex_lock_safe(&inode->i_mutex, inode->i_sb);
reiserfs_write_lock(inode->i_sb);
write_from = inode->i_size & (blocksize - 1);
/* if we are on a block boundary, we are already unpacked. */
if (write_from == 0) {
REISERFS_I(inode)->i_flags |= i_nopack_mask;
goto out;
}
/* we unpack by finding the page with the tail, and calling
** __reiserfs_write_begin on that page. This will force a
** reiserfs_get_block to unpack the tail for us.
*/
index = inode->i_size >> PAGE_CACHE_SHIFT;
mapping = inode->i_mapping;
page = grab_cache_page(mapping, index);
retval = -ENOMEM;
if (!page) {
goto out;
}
retval = __reiserfs_write_begin(page, write_from, 0);
if (retval)
goto out_unlock;
/* conversion can change page contents, must flush */
flush_dcache_page(page);
retval = reiserfs_commit_write(NULL, page, write_from, write_from);
REISERFS_I(inode)->i_flags |= i_nopack_mask;
out_unlock:
unlock_page(page);
page_cache_release(page);
out:
mutex_unlock(&inode->i_mutex);
reiserfs_write_unlock(inode->i_sb);
return retval;
}