| From | Ben Hutchings <> | Date | Fri, 10 Mar 2017 11:46:10 +0000 | Subject | [PATCH 3.2 140/199] btrfs: fix btrfs_compat_ioctl failures on non-compat ioctls |
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3.2.87-rc1 review patch. If anyone has any objections, please let me know.
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From: Jeff Mahoney <jeffm@suse.com>
commit 2a362249187a8d0f6d942d6e1d763d150a296f47 upstream.
Commit 4c63c2454ef incorrectly assumed that returning -ENOIOCTLCMD would cause the native ioctl to be called. The ->compat_ioctl callback is expected to handle all ioctls, not just compat variants. As a result, when using 32-bit userspace on 64-bit kernels, everything except those three ioctls would return -ENOTTY.
Fixes: 4c63c2454ef ("btrfs: bugfix: handle FS_IOC32_{GETFLAGS,SETFLAGS,GETVERSION} in btrfs_ioctl") Signed-off-by: Jeff Mahoney <jeffm@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> --- fs/btrfs/ioctl.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
--- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -3276,6 +3276,10 @@ long btrfs_ioctl(struct file *file, unsi #ifdef CONFIG_COMPAT long btrfs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { + /* + * These all access 32-bit values anyway so no further + * handling is necessary. + */ switch (cmd) { case FS_IOC32_GETFLAGS: cmd = FS_IOC_GETFLAGS; @@ -3286,8 +3290,6 @@ long btrfs_compat_ioctl(struct file *fil case FS_IOC32_GETVERSION: cmd = FS_IOC_GETVERSION; break; - default: - return -ENOIOCTLCMD; } return btrfs_ioctl(file, cmd, (unsigned long) compat_ptr(arg));
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