Re: [PATCH] ceph: Fix file open flags on ppc64

From: Jeff Layton
Date: Fri Apr 21 2017 - 09:46:26 EST


On Thu, 2017-04-20 at 14:40 +0200, Alexander Graf wrote:
> The file open flags (O_foo) are platform specific and should never go
> out to an interface that is not local to the system.
>
> Unfortunately these flags have leaked out onto the wire in the cephfs
> implementation. That lead to bogus flags getting transmitted on ppc64.
>
> This patch converts the kernel view of flags to the ceph view of file
> open flags. On x86 systems, the new function should get optimized out
> by smart compilers. On systems where the flags differ, it should adapt
> them accordingly.
>
> Fixes: 124e68e74 ("ceph: file operations")
> Signed-off-by: Alexander Graf <agraf@xxxxxxx>
> ---
> fs/ceph/file.c | 45 +++++++++++++++++++++++++++++++++++++++++++-
> include/linux/ceph/ceph_fs.h | 24 +++++++++++++++++++++++
> 2 files changed, 68 insertions(+), 1 deletion(-)
>
> diff --git a/fs/ceph/file.c b/fs/ceph/file.c
> index 26cc954..0ed6392 100644
> --- a/fs/ceph/file.c
> +++ b/fs/ceph/file.c
> @@ -103,6 +103,49 @@ static size_t dio_get_pagev_size(const struct iov_iter *it)
> return ERR_PTR(ret);
> }
>
> +static u32 ceph_flags_sys2wire(u32 flags)
> +{
> + u32 wire_flags = 0;
> +
> + switch (flags & O_ACCMODE) {
> + case O_RDONLY:
> + wire_flags |= CEPH_O_RDONLY;
> + break;
> + case O_WRONLY:
> + wire_flags |= CEPH_O_WRONLY;
> + break;
> + case O_RDWR:
> + wire_flags |= CEPH_O_RDWR;
> + break;
> + }
> + flags &= ~O_ACCMODE;
> +
> +#define ceph_sys2wire(a) if (flags & a) { wire_flags |= CEPH_##a; flags &= ~a; }
> +
> + ceph_sys2wire(O_CREAT);
> + ceph_sys2wire(O_NOCTTY);
> + ceph_sys2wire(O_TRUNC);
> + ceph_sys2wire(O_APPEND);
> + ceph_sys2wire(O_NONBLOCK);
> + ceph_sys2wire(O_DSYNC);
> + ceph_sys2wire(FASYNC);
> + ceph_sys2wire(O_DIRECT);
> + ceph_sys2wire(O_LARGEFILE);
> + ceph_sys2wire(O_DIRECTORY);
> + ceph_sys2wire(O_NOFOLLOW);
> + ceph_sys2wire(O_NOATIME);
> + ceph_sys2wire(O_CLOEXEC);
> + ceph_sys2wire(__O_SYNC);
> + ceph_sys2wire(O_PATH);
> + ceph_sys2wire(__O_TMPFILE);
> +
> +#undef ceph_sys2wire
> +
> + WARN_ONCE(flags, "Found unknown open flags: %x", flags);
> +
> + return wire_flags;
> +}
> +
> /*
> * Prepare an open request. Preallocate ceph_cap to avoid an
> * inopportune ENOMEM later.
> @@ -123,7 +166,7 @@ static size_t dio_get_pagev_size(const struct iov_iter *it)
> if (IS_ERR(req))
> goto out;
> req->r_fmode = ceph_flags_to_mode(flags);
> - req->r_args.open.flags = cpu_to_le32(flags);
> + req->r_args.open.flags = ceph_flags_sys2wire(cpu_to_le32(flags));

Shouldn't that be:

req->r_args.open.flags = cpu_to_le32(ceph_flags_sys2wire(flags));

It might be best though to move the cpu_to_le32 conversion into
ceph_flags_sys2wire instead.

> req->r_args.open.mode = cpu_to_le32(create_mode);
> out:
> return req;
> diff --git a/include/linux/ceph/ceph_fs.h b/include/linux/ceph/ceph_fs.h
> index f4b2ee1..d254b48 100644
> --- a/include/linux/ceph/ceph_fs.h
> +++ b/include/linux/ceph/ceph_fs.h
> @@ -366,6 +366,30 @@ enum {
> #define CEPH_READDIR_FRAG_COMPLETE (1<<8)
> #define CEPH_READDIR_HASH_ORDER (1<<9)
>
> +/*
> + * open request flags
> + */
> +#define CEPH_O_RDONLY 00000000
> +#define CEPH_O_WRONLY 00000001
> +#define CEPH_O_RDWR 00000002
> +#define CEPH_O_CREAT 00000100
> +#define CEPH_O_EXCL 00000200
> +#define CEPH_O_NOCTTY 00000400
> +#define CEPH_O_TRUNC 00001000
> +#define CEPH_O_APPEND 00002000
> +#define CEPH_O_NONBLOCK 00004000
> +#define CEPH_O_DSYNC 00010000
> +#define CEPH_FASYNC 00020000
> +#define CEPH_O_DIRECT 00040000
> +#define CEPH_O_LARGEFILE 00100000
> +#define CEPH_O_DIRECTORY 00200000
> +#define CEPH_O_NOFOLLOW 00400000
> +#define CEPH_O_NOATIME 01000000
> +#define CEPH_O_CLOEXEC 02000000
> +#define CEPH___O_SYNC 04000000
> +#define CEPH_O_PATH 010000000
> +#define CEPH___O_TMPFILE 020000000
> +
> union ceph_mds_request_args {
> struct {
> __le32 mask; /* CEPH_CAP_* */

--
Jeff Layton <jlayton@xxxxxxxxxx>