Hugo Mills
2014-Jan-05 17:55 UTC
[PATCH] btrfs: Fix 32/64-bit problem with BTRFS_SET_RECEIVED_SUBVOL ioctl
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.
Signed-off-by: Hugo Mills <hugo@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:
--
1.8.5.1
--
To unsubscribe from this list: send the line "unsubscribe linux-btrfs"
in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html