Re: Build failures due to commit 416161db (btrfs: offline dedupe)

Mark Fasheh
2013-09-17T22:43:58Z

On Fri, Sep 13, 2013 at 03:33:34PM -0400, Chris Mason wrote:
> Mark, could you please send a patch for the whole-struct option until
> the unaligned put is upstreamed?
>
> -chris

Here you go. It's been lightly tested and needs review.

Thanks,
--Mark

--
Mark Fasheh

From: Mark Fasheh <mfasheh@suse.de>

[PATCH] btrfs: change extent-same to copy entire argument struct

btrfs_ioctl_file_extent_same() uses __put_user_unaligned() to copy some data
back to it's argument struct. Unfortunately, not all architectures provide
__put_user_unaligned(), so compiles break on them if btrfs is selected.

Instead, just copy the whole struct in / out at the start and end of
operations, respectively.

Signed-off-by: Mark Fasheh <mfasheh@suse.de>
---
fs/btrfs/ioctl.c | 76 +++++++++++++++++++++++++++++++++-----------------------
1 file changed, 45 insertions(+), 31 deletions(-)

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 1a5b946..25d6920 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -2696,9 +2696,9 @@ out_unlock:
static long btrfs_ioctl_file_extent_same(struct file *file,
void __user *argp)
{
- struct btrfs_ioctl_same_args *args = argp;
- struct btrfs_ioctl_same_args same;
- struct btrfs_ioctl_same_extent_info info;
+ struct btrfs_ioctl_same_args tmp;
+ struct btrfs_ioctl_same_args *same;
+ struct btrfs_ioctl_same_extent_info *info;
struct inode *src = file->f_dentry->d_inode;
struct file *dst_file = NULL;
struct inode *dst;
@@ -2706,6 +2706,7 @@ static long btrfs_ioctl_file_extent_same(struct file *file,
u64 len;
int i;
int ret;
+ unsigned long size;
u64 bs = BTRFS_I(src)->root->fs_info->sb->s_blocksize;
bool is_admin = capable(CAP_SYS_ADMIN);

@@ -2716,15 +2717,30 @@ static long btrfs_ioctl_file_extent_same(struct file *file,
if (ret)
return ret;

- if (copy_from_user(&same,
+ if (copy_from_user(&tmp,
(struct btrfs_ioctl_same_args __user *)argp,
- sizeof(same))) {
+ sizeof(tmp))) {
ret = -EFAULT;
goto out;
}

- off = same.logical_offset;
- len = same.length;
+ size = sizeof(tmp) +
+ tmp.dest_count * sizeof(struct btrfs_ioctl_same_extent_info);
+
+ same = kmalloc(size, GFP_NOFS);
+ if (!same) {
+ ret = -EFAULT;
+ goto out;
+ }
+
+ if (copy_from_user(same,
+ (struct btrfs_ioctl_same_args __user *)argp, size)) {
+ ret = -EFAULT;
+ goto out;
+ }
+
+ off = same->logical_offset;
+ len = same->length;

/*
* Limit the total length we will dedupe for each operation.
@@ -2752,27 +2768,28 @@ static long btrfs_ioctl_file_extent_same(struct file *file,
if (!S_ISREG(src->i_mode))
goto out;

- ret = 0;
- for (i = 0; i < same.dest_count; i++) {
- if (copy_from_user(&info, &args->info[i], sizeof(info))) {
- ret = -EFAULT;
- goto out;
- }
+ /* pre-format output fields to sane values */
+ for (i = 0; i < same->dest_count; i++) {
+ same->info[i].bytes_deduped = 0ULL;
+ same->info[i].status = 0;
+ }

- info.bytes_deduped = 0;
+ ret = 0;
+ for (i = 0; i < same->dest_count; i++) {
+ info = &same->info[i];

- dst_file = fget(info.fd);
+ dst_file = fget(info->fd);
if (!dst_file) {
- info.status = -EBADF;
+ info->status = -EBADF;
goto next;
}

if (!(is_admin || (dst_file->f_mode & FMODE_WRITE))) {
- info.status = -EINVAL;
+ info->status = -EINVAL;
goto next;
}

- info.status = -EXDEV;
+ info->status = -EXDEV;
if (file->f_path.mnt != dst_file->f_path.mnt)
goto next;

@@ -2781,32 +2798,29 @@ static long btrfs_ioctl_file_extent_same(struct file *file,
goto next;

if (S_ISDIR(dst->i_mode)) {
- info.status = -EISDIR;
+ info->status = -EISDIR;
goto next;
}

if (!S_ISREG(dst->i_mode)) {
- info.status = -EACCES;
+ info->status = -EACCES;
goto next;
}

- info.status = btrfs_extent_same(src, off, len, dst,
- info.logical_offset);
- if (info.status == 0)
- info.bytes_deduped += len;
+ info->status = btrfs_extent_same(src, off, len, dst,
+ info->logical_offset);
+ if (info->status == 0)
+ info->bytes_deduped += len;

next:
if (dst_file)
fput(dst_file);
-
- if (__put_user_unaligned(info.status, &args->info[i].status) ||
- __put_user_unaligned(info.bytes_deduped,
- &args->info[i].bytes_deduped)) {
- ret = -EFAULT;
- goto out;
- }
}

+ ret = copy_to_user(argp, same, size);
+ if (ret)
+ ret = -EFAULT;
+
out:
mnt_drop_write_file(file);
return ret;
--
1.8.1.4