On Sun, Jan 05, 2014 at 05:55:27PM +0000, Hugo Mills wrote: > The structure for BTRFS_SET_RECEIVED_IOCTL packs differently on 32-bit > and 64-bit systems. This means that it is impossible to use btrfs > receive on a system with a 64-bit kernel and 32-bit userspace, because > the structure size (and hence the ioctl number) is different. > > This patch adds a compatibility structure and ioctl to deal with the > above case.
Oops, forgot to mention -- this has been compile tested, but not
actually run yet. The machine in question is several miles away and is
a production machine (it's my work desktop, and I can't afford much
downtime on it).
Hugo.
> Signed-off-by: Hugo Mills <h...@carfax.org.uk>
> ---
> fs/btrfs/ioctl.c | 95
> +++++++++++++++++++++++++++++++++++++++++++++++++++-----
> 1 file changed, 87 insertions(+), 8 deletions(-)
>
> diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
> index 21da576..e186439 100644
> --- a/fs/btrfs/ioctl.c
> +++ b/fs/btrfs/ioctl.c
> @@ -57,6 +57,32 @@
> #include "send.h"
> #include "dev-replace.h"
>
> +#ifdef CONFIG_64BIT
> +/* If we have a 32-bit userspace and 64-bit kernel, then the UAPI
> + * structures are incorrect, as the timespec structure from userspace
> + * is 4 bytes too small. We define these alternatives here to teach
> + * the kernel about the 32-bit struct packing.
> + */
> +struct btrfs_ioctl_timespec {
> + __u64 sec;
> + __u32 nsec;
> +} ((__packed__));
> +
> +struct btrfs_ioctl_received_subvol_args {
> + char uuid[BTRFS_UUID_SIZE]; /* in */
> + __u64 stransid; /* in */
> + __u64 rtransid; /* out */
> + struct btrfs_ioctl_timespec stime; /* in */
> + struct btrfs_ioctl_timespec rtime; /* out */
> + __u64 flags; /* in */
> + __u64 reserved[16]; /* in */
> +} ((__packed__));
> +#endif
> +
> +#define BTRFS_IOC_SET_RECEIVED_SUBVOL_32 _IOWR(BTRFS_IOCTL_MAGIC, 37, \
> + struct btrfs_ioctl_received_subvol_args_32)
> +
> +
> static int btrfs_clone(struct inode *src, struct inode *inode,
> u64 off, u64 olen, u64 olen_aligned, u64 destoff);
>
> @@ -4313,10 +4339,69 @@ static long btrfs_ioctl_quota_rescan_wait(struct file
> *file, void __user *arg)
> return btrfs_qgroup_wait_for_completion(root->fs_info);
> }
>
> +#ifdef CONFIG_64BIT
> +static long btrfs_ioctl_set_received_subvol_32(struct file *file,
> + void __user *arg)
> +{
> + struct btrfs_ioctl_received_subvol_args_32 *args32 = NULL;
> + struct btrfs_ioctl_received_subvol_args *args64 = NULL;
> + int ret = 0;
> +
> + args32 = memdup_user(arg, sizeof(*args32));
> + if (IS_ERR(args32)) {
> + ret = PTR_ERR(args32);
> + args32 = NULL;
> + goto out;
> + }
> +
> + args64 = malloc(sizeof(*args64));
> + if (IS_ERR(args64)) {
> + ret = PTR_ERR(args64);
> + args64 = NULL;
> + goto out;
> + }
> +
> + memcpy(args64->uuid, args32->uuid, BTRFS_UUID_SIZE);
> + args64->stransid = args32->stransid;
> + args64->rtransid = args32->rtransid;
> + args64->stime.sec = args32->stime.sec;
> + args64->stime.nsec = args32->stime.nsec;
> + args64->rtime.sec = args32->rtime.sec;
> + args64->rtime.nsec = args32->rtime.nsec;
> + args64->flags = args32->flags;
> +
> + ret = _btrfs_ioctl_set_received_subvol(file, args64);
> +
> +out:
> + kfree(args32);
> + kfree(args64);
> + return ret;
> +}
> +#endif
> +
> static long btrfs_ioctl_set_received_subvol(struct file *file,
> void __user *arg)
> {
> struct btrfs_ioctl_received_subvol_args *sa = NULL;
> + int ret = 0;
> +
> + sa = memdup_user(arg, sizeof(*sa));
> + if (IS_ERR(sa)) {
> + ret = PTR_ERR(sa);
> + sa = NULL;
> + goto out;
> + }
> +
> + ret = _btrfs_ioctl_set_received_subvol(file, sa);
> +
> +out:
> + kfree(sa);
> + return ret;
> +}
> +
> +static long _btrfs_ioctl_set_received_subvol(struct file *file,
> + struct
> btrfs_ioctl_received_subvol_args *sa)
> +{
> struct inode *inode = file_inode(file);
> struct btrfs_root *root = BTRFS_I(inode)->root;
> struct btrfs_root_item *root_item = &root->root_item;
> @@ -4346,13 +4431,6 @@ static long btrfs_ioctl_set_received_subvol(struct
> file *file,
> goto out;
> }
>
> - sa = memdup_user(arg, sizeof(*sa));
> - if (IS_ERR(sa)) {
> - ret = PTR_ERR(sa);
> - sa = NULL;
> - goto out;
> - }
> -
> /*
> * 1 - root item
> * 2 - uuid items (received uuid + subvol uuid)
> @@ -4411,7 +4489,6 @@ static long btrfs_ioctl_set_received_subvol(struct file
> *file,
> ret = -EFAULT;
>
> out:
> - kfree(sa);
> up_write(&root->fs_info->subvol_sem);
> mnt_drop_write_file(file);
> return ret;
> @@ -4572,6 +4649,8 @@ long btrfs_ioctl(struct file *file, unsigned int
> return btrfs_ioctl_balance_progress(root, argp);
> case BTRFS_IOC_SET_RECEIVED_SUBVOL:
> return btrfs_ioctl_set_received_subvol(file, argp);
> + case BTRFS_IOC_SET_RECEIVED_SUBVOL_32:
> + return btrfs_ioctl_set_received_subvol_32(file, argp);
> case BTRFS_IOC_SEND:
> return btrfs_ioctl_send(file, argp);
> case BTRFS_IOC_GET_DEV_STATS:
--
=== Hugo Mills: hugo@... carfax.org.uk | darksatanic.net | lug.org.uk ===
PGP key: 65E74AC0 from wwwkeys.eu.pgp.net or http://www.carfax.org.uk
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