linux/fs/ioctl.c
Josef Bacik df3935ffd6 fiemap: fix problem with setting FIEMAP_EXTENT_LAST
Fix a problem where the generic block based fiemap stuff would not
properly set FIEMAP_EXTENT_LAST on the last extent.  I've reworked things
to keep track if we go past the EOF, and mark the last extent properly.
The problem was reported by and tested by Eric Sandeen.

Tested-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Cc: <linux-ext4@vger.kernel.org>
Cc: <xfs-masters@oss.sgi.com>
Cc: <linux-btrfs@vger.kernel.org>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <Joel.Becker@oracle.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-05-06 16:36:09 -07:00

596 lines
15 KiB
C

/*
* linux/fs/ioctl.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
*/
#include <linux/syscalls.h>
#include <linux/mm.h>
#include <linux/smp_lock.h>
#include <linux/capability.h>
#include <linux/file.h>
#include <linux/fs.h>
#include <linux/security.h>
#include <linux/module.h>
#include <linux/uaccess.h>
#include <linux/writeback.h>
#include <linux/buffer_head.h>
#include <asm/ioctls.h>
/* So that the fiemap access checks can't overflow on 32 bit machines. */
#define FIEMAP_MAX_EXTENTS (UINT_MAX / sizeof(struct fiemap_extent))
/**
* vfs_ioctl - call filesystem specific ioctl methods
* @filp: open file to invoke ioctl method on
* @cmd: ioctl command to execute
* @arg: command-specific argument for ioctl
*
* Invokes filesystem specific ->unlocked_ioctl, if one exists; otherwise
* invokes filesystem specific ->ioctl method. If neither method exists,
* returns -ENOTTY.
*
* Returns 0 on success, -errno on error.
*/
static long vfs_ioctl(struct file *filp, unsigned int cmd,
unsigned long arg)
{
int error = -ENOTTY;
if (!filp->f_op)
goto out;
if (filp->f_op->unlocked_ioctl) {
error = filp->f_op->unlocked_ioctl(filp, cmd, arg);
if (error == -ENOIOCTLCMD)
error = -EINVAL;
goto out;
} else if (filp->f_op->ioctl) {
lock_kernel();
error = filp->f_op->ioctl(filp->f_path.dentry->d_inode,
filp, cmd, arg);
unlock_kernel();
}
out:
return error;
}
static int ioctl_fibmap(struct file *filp, int __user *p)
{
struct address_space *mapping = filp->f_mapping;
int res, block;
/* do we support this mess? */
if (!mapping->a_ops->bmap)
return -EINVAL;
if (!capable(CAP_SYS_RAWIO))
return -EPERM;
res = get_user(block, p);
if (res)
return res;
lock_kernel();
res = mapping->a_ops->bmap(mapping, block);
unlock_kernel();
return put_user(res, p);
}
/**
* fiemap_fill_next_extent - Fiemap helper function
* @fieinfo: Fiemap context passed into ->fiemap
* @logical: Extent logical start offset, in bytes
* @phys: Extent physical start offset, in bytes
* @len: Extent length, in bytes
* @flags: FIEMAP_EXTENT flags that describe this extent
*
* Called from file system ->fiemap callback. Will populate extent
* info as passed in via arguments and copy to user memory. On
* success, extent count on fieinfo is incremented.
*
* Returns 0 on success, -errno on error, 1 if this was the last
* extent that will fit in user array.
*/
#define SET_UNKNOWN_FLAGS (FIEMAP_EXTENT_DELALLOC)
#define SET_NO_UNMOUNTED_IO_FLAGS (FIEMAP_EXTENT_DATA_ENCRYPTED)
#define SET_NOT_ALIGNED_FLAGS (FIEMAP_EXTENT_DATA_TAIL|FIEMAP_EXTENT_DATA_INLINE)
int fiemap_fill_next_extent(struct fiemap_extent_info *fieinfo, u64 logical,
u64 phys, u64 len, u32 flags)
{
struct fiemap_extent extent;
struct fiemap_extent *dest = fieinfo->fi_extents_start;
/* only count the extents */
if (fieinfo->fi_extents_max == 0) {
fieinfo->fi_extents_mapped++;
return (flags & FIEMAP_EXTENT_LAST) ? 1 : 0;
}
if (fieinfo->fi_extents_mapped >= fieinfo->fi_extents_max)
return 1;
if (flags & SET_UNKNOWN_FLAGS)
flags |= FIEMAP_EXTENT_UNKNOWN;
if (flags & SET_NO_UNMOUNTED_IO_FLAGS)
flags |= FIEMAP_EXTENT_ENCODED;
if (flags & SET_NOT_ALIGNED_FLAGS)
flags |= FIEMAP_EXTENT_NOT_ALIGNED;
memset(&extent, 0, sizeof(extent));
extent.fe_logical = logical;
extent.fe_physical = phys;
extent.fe_length = len;
extent.fe_flags = flags;
dest += fieinfo->fi_extents_mapped;
if (copy_to_user(dest, &extent, sizeof(extent)))
return -EFAULT;
fieinfo->fi_extents_mapped++;
if (fieinfo->fi_extents_mapped == fieinfo->fi_extents_max)
return 1;
return (flags & FIEMAP_EXTENT_LAST) ? 1 : 0;
}
EXPORT_SYMBOL(fiemap_fill_next_extent);
/**
* fiemap_check_flags - check validity of requested flags for fiemap
* @fieinfo: Fiemap context passed into ->fiemap
* @fs_flags: Set of fiemap flags that the file system understands
*
* Called from file system ->fiemap callback. This will compute the
* intersection of valid fiemap flags and those that the fs supports. That
* value is then compared against the user supplied flags. In case of bad user
* flags, the invalid values will be written into the fieinfo structure, and
* -EBADR is returned, which tells ioctl_fiemap() to return those values to
* userspace. For this reason, a return code of -EBADR should be preserved.
*
* Returns 0 on success, -EBADR on bad flags.
*/
int fiemap_check_flags(struct fiemap_extent_info *fieinfo, u32 fs_flags)
{
u32 incompat_flags;
incompat_flags = fieinfo->fi_flags & ~(FIEMAP_FLAGS_COMPAT & fs_flags);
if (incompat_flags) {
fieinfo->fi_flags = incompat_flags;
return -EBADR;
}
return 0;
}
EXPORT_SYMBOL(fiemap_check_flags);
static int fiemap_check_ranges(struct super_block *sb,
u64 start, u64 len, u64 *new_len)
{
*new_len = len;
if (len == 0)
return -EINVAL;
if (start > sb->s_maxbytes)
return -EFBIG;
/*
* Shrink request scope to what the fs can actually handle.
*/
if ((len > sb->s_maxbytes) ||
(sb->s_maxbytes - len) < start)
*new_len = sb->s_maxbytes - start;
return 0;
}
static int ioctl_fiemap(struct file *filp, unsigned long arg)
{
struct fiemap fiemap;
struct fiemap_extent_info fieinfo = { 0, };
struct inode *inode = filp->f_path.dentry->d_inode;
struct super_block *sb = inode->i_sb;
u64 len;
int error;
if (!inode->i_op->fiemap)
return -EOPNOTSUPP;
if (copy_from_user(&fiemap, (struct fiemap __user *)arg,
sizeof(struct fiemap)))
return -EFAULT;
if (fiemap.fm_extent_count > FIEMAP_MAX_EXTENTS)
return -EINVAL;
error = fiemap_check_ranges(sb, fiemap.fm_start, fiemap.fm_length,
&len);
if (error)
return error;
fieinfo.fi_flags = fiemap.fm_flags;
fieinfo.fi_extents_max = fiemap.fm_extent_count;
fieinfo.fi_extents_start = (struct fiemap_extent *)(arg + sizeof(fiemap));
if (fiemap.fm_extent_count != 0 &&
!access_ok(VERIFY_WRITE, fieinfo.fi_extents_start,
fieinfo.fi_extents_max * sizeof(struct fiemap_extent)))
return -EFAULT;
if (fieinfo.fi_flags & FIEMAP_FLAG_SYNC)
filemap_write_and_wait(inode->i_mapping);
error = inode->i_op->fiemap(inode, &fieinfo, fiemap.fm_start, len);
fiemap.fm_flags = fieinfo.fi_flags;
fiemap.fm_mapped_extents = fieinfo.fi_extents_mapped;
if (copy_to_user((char *)arg, &fiemap, sizeof(fiemap)))
error = -EFAULT;
return error;
}
#ifdef CONFIG_BLOCK
#define blk_to_logical(inode, blk) (blk << (inode)->i_blkbits)
#define logical_to_blk(inode, offset) (offset >> (inode)->i_blkbits);
/**
* __generic_block_fiemap - FIEMAP for block based inodes (no locking)
* @inode - the inode to map
* @arg - the pointer to userspace where we copy everything to
* @get_block - the fs's get_block function
*
* This does FIEMAP for block based inodes. Basically it will just loop
* through get_block until we hit the number of extents we want to map, or we
* go past the end of the file and hit a hole.
*
* If it is possible to have data blocks beyond a hole past @inode->i_size, then
* please do not use this function, it will stop at the first unmapped block
* beyond i_size.
*
* If you use this function directly, you need to do your own locking. Use
* generic_block_fiemap if you want the locking done for you.
*/
int __generic_block_fiemap(struct inode *inode,
struct fiemap_extent_info *fieinfo, u64 start,
u64 len, get_block_t *get_block)
{
struct buffer_head tmp;
unsigned int start_blk;
long long length = 0, map_len = 0;
u64 logical = 0, phys = 0, size = 0;
u32 flags = FIEMAP_EXTENT_MERGED;
int ret = 0, past_eof = 0, whole_file = 0;
if ((ret = fiemap_check_flags(fieinfo, FIEMAP_FLAG_SYNC)))
return ret;
start_blk = logical_to_blk(inode, start);
length = (long long)min_t(u64, len, i_size_read(inode));
if (length < len)
whole_file = 1;
map_len = length;
do {
/*
* we set b_size to the total size we want so it will map as
* many contiguous blocks as possible at once
*/
memset(&tmp, 0, sizeof(struct buffer_head));
tmp.b_size = map_len;
ret = get_block(inode, start_blk, &tmp, 0);
if (ret)
break;
/* HOLE */
if (!buffer_mapped(&tmp)) {
length -= blk_to_logical(inode, 1);
start_blk++;
/*
* we want to handle the case where there is an
* allocated block at the front of the file, and then
* nothing but holes up to the end of the file properly,
* to make sure that extent at the front gets properly
* marked with FIEMAP_EXTENT_LAST
*/
if (!past_eof &&
blk_to_logical(inode, start_blk) >=
blk_to_logical(inode, 0)+i_size_read(inode))
past_eof = 1;
/*
* first hole after going past the EOF, this is our
* last extent
*/
if (past_eof && size) {
flags = FIEMAP_EXTENT_MERGED|FIEMAP_EXTENT_LAST;
ret = fiemap_fill_next_extent(fieinfo, logical,
phys, size,
flags);
break;
}
/* if we have holes up to/past EOF then we're done */
if (length <= 0 || past_eof)
break;
} else {
/*
* we have gone over the length of what we wanted to
* map, and it wasn't the entire file, so add the extent
* we got last time and exit.
*
* This is for the case where say we want to map all the
* way up to the second to the last block in a file, but
* the last block is a hole, making the second to last
* block FIEMAP_EXTENT_LAST. In this case we want to
* see if there is a hole after the second to last block
* so we can mark it properly. If we found data after
* we exceeded the length we were requesting, then we
* are good to go, just add the extent to the fieinfo
* and break
*/
if (length <= 0 && !whole_file) {
ret = fiemap_fill_next_extent(fieinfo, logical,
phys, size,
flags);
break;
}
/*
* if size != 0 then we know we already have an extent
* to add, so add it.
*/
if (size) {
ret = fiemap_fill_next_extent(fieinfo, logical,
phys, size,
flags);
if (ret)
break;
}
logical = blk_to_logical(inode, start_blk);
phys = blk_to_logical(inode, tmp.b_blocknr);
size = tmp.b_size;
flags = FIEMAP_EXTENT_MERGED;
length -= tmp.b_size;
start_blk += logical_to_blk(inode, size);
/*
* If we are past the EOF, then we need to make sure as
* soon as we find a hole that the last extent we found
* is marked with FIEMAP_EXTENT_LAST
*/
if (!past_eof &&
logical+size >=
blk_to_logical(inode, 0)+i_size_read(inode))
past_eof = 1;
}
cond_resched();
} while (1);
/* if ret is 1 then we just hit the end of the extent array */
if (ret == 1)
ret = 0;
return ret;
}
EXPORT_SYMBOL(__generic_block_fiemap);
/**
* generic_block_fiemap - FIEMAP for block based inodes
* @inode: The inode to map
* @fieinfo: The mapping information
* @start: The initial block to map
* @len: The length of the extect to attempt to map
* @get_block: The block mapping function for the fs
*
* Calls __generic_block_fiemap to map the inode, after taking
* the inode's mutex lock.
*/
int generic_block_fiemap(struct inode *inode,
struct fiemap_extent_info *fieinfo, u64 start,
u64 len, get_block_t *get_block)
{
int ret;
mutex_lock(&inode->i_mutex);
ret = __generic_block_fiemap(inode, fieinfo, start, len, get_block);
mutex_unlock(&inode->i_mutex);
return ret;
}
EXPORT_SYMBOL(generic_block_fiemap);
#endif /* CONFIG_BLOCK */
static int file_ioctl(struct file *filp, unsigned int cmd,
unsigned long arg)
{
struct inode *inode = filp->f_path.dentry->d_inode;
int __user *p = (int __user *)arg;
switch (cmd) {
case FIBMAP:
return ioctl_fibmap(filp, p);
case FIONREAD:
return put_user(i_size_read(inode) - filp->f_pos, p);
}
return vfs_ioctl(filp, cmd, arg);
}
static int ioctl_fionbio(struct file *filp, int __user *argp)
{
unsigned int flag;
int on, error;
error = get_user(on, argp);
if (error)
return error;
flag = O_NONBLOCK;
#ifdef __sparc__
/* SunOS compatibility item. */
if (O_NONBLOCK != O_NDELAY)
flag |= O_NDELAY;
#endif
spin_lock(&filp->f_lock);
if (on)
filp->f_flags |= flag;
else
filp->f_flags &= ~flag;
spin_unlock(&filp->f_lock);
return error;
}
static int ioctl_fioasync(unsigned int fd, struct file *filp,
int __user *argp)
{
unsigned int flag;
int on, error;
error = get_user(on, argp);
if (error)
return error;
flag = on ? FASYNC : 0;
/* Did FASYNC state change ? */
if ((flag ^ filp->f_flags) & FASYNC) {
if (filp->f_op && filp->f_op->fasync)
/* fasync() adjusts filp->f_flags */
error = filp->f_op->fasync(fd, filp, on);
else
error = -ENOTTY;
}
return error < 0 ? error : 0;
}
static int ioctl_fsfreeze(struct file *filp)
{
struct super_block *sb = filp->f_path.dentry->d_inode->i_sb;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
/* If filesystem doesn't support freeze feature, return. */
if (sb->s_op->freeze_fs == NULL)
return -EOPNOTSUPP;
/* If a blockdevice-backed filesystem isn't specified, return. */
if (sb->s_bdev == NULL)
return -EINVAL;
/* Freeze */
sb = freeze_bdev(sb->s_bdev);
if (IS_ERR(sb))
return PTR_ERR(sb);
return 0;
}
static int ioctl_fsthaw(struct file *filp)
{
struct super_block *sb = filp->f_path.dentry->d_inode->i_sb;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
/* If a blockdevice-backed filesystem isn't specified, return EINVAL. */
if (sb->s_bdev == NULL)
return -EINVAL;
/* Thaw */
return thaw_bdev(sb->s_bdev, sb);
}
/*
* When you add any new common ioctls to the switches above and below
* please update compat_sys_ioctl() too.
*
* do_vfs_ioctl() is not for drivers and not intended to be EXPORT_SYMBOL()'d.
* It's just a simple helper for sys_ioctl and compat_sys_ioctl.
*/
int do_vfs_ioctl(struct file *filp, unsigned int fd, unsigned int cmd,
unsigned long arg)
{
int error = 0;
int __user *argp = (int __user *)arg;
switch (cmd) {
case FIOCLEX:
set_close_on_exec(fd, 1);
break;
case FIONCLEX:
set_close_on_exec(fd, 0);
break;
case FIONBIO:
error = ioctl_fionbio(filp, argp);
break;
case FIOASYNC:
error = ioctl_fioasync(fd, filp, argp);
break;
case FIOQSIZE:
if (S_ISDIR(filp->f_path.dentry->d_inode->i_mode) ||
S_ISREG(filp->f_path.dentry->d_inode->i_mode) ||
S_ISLNK(filp->f_path.dentry->d_inode->i_mode)) {
loff_t res =
inode_get_bytes(filp->f_path.dentry->d_inode);
error = copy_to_user((loff_t __user *)arg, &res,
sizeof(res)) ? -EFAULT : 0;
} else
error = -ENOTTY;
break;
case FIFREEZE:
error = ioctl_fsfreeze(filp);
break;
case FITHAW:
error = ioctl_fsthaw(filp);
break;
case FS_IOC_FIEMAP:
return ioctl_fiemap(filp, arg);
case FIGETBSZ:
{
struct inode *inode = filp->f_path.dentry->d_inode;
int __user *p = (int __user *)arg;
return put_user(inode->i_sb->s_blocksize, p);
}
default:
if (S_ISREG(filp->f_path.dentry->d_inode->i_mode))
error = file_ioctl(filp, cmd, arg);
else
error = vfs_ioctl(filp, cmd, arg);
break;
}
return error;
}
SYSCALL_DEFINE3(ioctl, unsigned int, fd, unsigned int, cmd, unsigned long, arg)
{
struct file *filp;
int error = -EBADF;
int fput_needed;
filp = fget_light(fd, &fput_needed);
if (!filp)
goto out;
error = security_file_ioctl(filp, cmd, arg);
if (error)
goto out_fput;
error = do_vfs_ioctl(filp, fd, cmd, arg);
out_fput:
fput_light(filp, fput_needed);
out:
return error;
}