Re: [PATCH 5/6] statx: Make windows attributes available for CIFS, NTFS and FAT to use

Andreas Dilger
2016-05-02T22:52:12Z

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On Apr 29, 2016, at 6:58 AM, David Howells <dhowells@redhat.com> wrote:
>
> Make windows attributes available for CIFS, NTFS and FAT to use in the
> statx struct. The attribute flags map directly by value to those in the
> CIFS PDU flags. Some of these bits can also be used by JFS, UFS and HPFS.
>
> The statx struct acquires:
>
> __u32 st_win_attrs;

It seems some of these flags are duplicated with the st_information field,
and some are duplicate with FS_IOC_GETFLAGS values, and returning the same
information in multiple ways is confusing.

If these flags are part of the CIFS protocol, and are directly usable by
Samba then I can understand we wouldn't want to change them once in the
kernel and then convert them back in userspace, but I'm a bit reluctant
to have flags only for CIFS/NTFS/FAT that might also be useful for other filesystems. Would we want to be able to get translated st_win_attrs
flags in ext4 attrs when it is being exported by Samba?

> The value in this is present if STATX_WIN_ATTRS is set.
>
> The defined flags in this are:
>
> STATX_WIN_ATTR_READONLY
> STATX_WIN_ATTR_HIDDEN
> STATX_WIN_ATTR_SYSTEM
> STATX_WIN_ATTR_DIRECTORY

How does this differ from (st_mode & S_IFMT) == S_IFDIR)?

> STATX_WIN_ATTR_ARCHIVE
> STATX_WIN_ATTR_NORMAL

How does this differ from (st_mode & S_IFMT) == S_IFREG)?

> STATX_WIN_ATTR_TEMPORARY

How does this differ from STATX_INFO_TEMPORARY?

> STATX_WIN_ATTR_SPARSE_FILE
> STATX_WIN_ATTR_REPARSE_POINT
> STATX_WIN_ATTR_COMPRESSED
> STATX_WIN_ATTR_OFFLINE
> STATX_WIN_ATTR_NOT_CONTENT_INDEXED
> STATX_WIN_ATTR_ENCRYPTED

How does this differ from STATX_INFO_ENCRYPTED?

Cheers, Andreas

> STATX_WIN_ATTR_INTEGRITY_STREAM
> STATX_WIN_ATTR_NO_SCRUB_DATA
>
> Signed-off-by: David Howells <dhowells@redhat.com>
> ---
>
> fs/stat.c | 5 ++++-
> include/uapi/linux/stat.h | 30 ++++++++++++++++++++++++++++--
> samples/statx/test-statx.c | 31 +++++++++++++++++++++++++++++++
> 3 files changed, 63 insertions(+), 3 deletions(-)
>
> diff --git a/fs/stat.c b/fs/stat.c
> index c2f8370dab13..1552bff154e6 100644
> --- a/fs/stat.c
> +++ b/fs/stat.c
> @@ -83,6 +83,7 @@ int vfs_xgetattr_nosec(struct path *path, struct kstat *stat)
>
> stat->result_mask = 0;
> stat->information = 0;
> + stat->win_attrs = 0;
> if (inode->i_op->getattr)
> return inode->i_op->getattr(path->mnt, path->dentry, stat);
>
> @@ -643,7 +644,9 @@ static long statx_set_result(struct kstat *stat, struct statx __user *buffer)
> __put_user(stat->blocks, &buffer->st_blocks ) ||
> __put_user(stat->version, &buffer->st_version ) ||
> __put_user(stat->gen, &buffer->st_gen ) ||
> - __clear_user(&buffer->__spare1, sizeof(buffer->__spare1)))
> + __put_user(stat->win_attrs, &buffer->st_win_attrs ) ||
> + __clear_user(&buffer->__spare1,
> + sizeof(buffer->__spare1) + sizeof(buffer->__spare2)))
> return -EFAULT;
>
> return 0;
> diff --git a/include/uapi/linux/stat.h b/include/uapi/linux/stat.h
> index 55ce6607dab6..64729b0785bf 100644
> --- a/include/uapi/linux/stat.h
> +++ b/include/uapi/linux/stat.h
> @@ -106,7 +106,10 @@ struct statx {
> __u32 st_dev_major; /* ID of device containing file [uncond] */
> __u32 st_dev_minor;
> /* 0x80 */
> - __u64 __spare1[16]; /* Spare space for future expansion */
> + __u32 st_win_attrs; /* Windows file attributes */
> + __u32 __spare1[3];
> + /* 0x90 */
> + __u64 __spare2[14]; /* Spare space for future expansion */
> /* 0x100 */
> };
>
> @@ -133,7 +136,8 @@ struct statx {
> #define STATX_BTIME 0x00000800U /* Want/got st_btime */
> #define STATX_VERSION 0x00001000U /* Want/got st_version */
> #define STATX_GEN 0x00002000U /* Want/got st_gen */
> -#define STATX_ALL_STATS 0x00003fffU /* All supported stats */
> +#define STATX_WIN_ATTRS 0x00004000U /* Want/got st_win_attrs */
> +#define STATX_ALL_STATS 0x00007fffU /* All supported stats */
>
> /*
> * Flags to be found in st_information
> @@ -151,4 +155,26 @@ struct statx {
> #define STATX_INFO_AUTODIR 0x00000040U /* Dir provides unlisted automounts */
> #define STATX_INFO_NONSYSTEM_OWNERSHIP 0x00000080U /* File has non-system ownership details */
>
> +/*
> + * Flags to be found in st_win_attrs.
> + *
> + * These give information about the state of a file on a Windows filesystem
> + * (such as. FAT, NTFS, CIFS). These values are borrowed from the CIFS fs.
> + */
> +#define STATX_WIN_ATTR_READONLY 0x00000001
> +#define STATX_WIN_ATTR_HIDDEN 0x00000002
> +#define STATX_WIN_ATTR_SYSTEM 0x00000004
> +#define STATX_WIN_ATTR_DIRECTORY 0x00000010
> +#define STATX_WIN_ATTR_ARCHIVE 0x00000020
> +#define STATX_WIN_ATTR_NORMAL 0x00000080
> +#define STATX_WIN_ATTR_TEMPORARY 0x00000100
> +#define STATX_WIN_ATTR_SPARSE_FILE 0x00000200
> +#define STATX_WIN_ATTR_REPARSE_POINT 0x00000400
> +#define STATX_WIN_ATTR_COMPRESSED 0x00000800
> +#define STATX_WIN_ATTR_OFFLINE 0x00001000
> +#define STATX_WIN_ATTR_NOT_CONTENT_INDEXED 0x00002000
> +#define STATX_WIN_ATTR_ENCRYPTED 0x00004000
> +#define STATX_WIN_ATTR_INTEGRITY_STREAM 0x00008000
> +#define STATX_WIN_ATTR_NO_SCRUB_DATA 0x00020000
> +
> #endif /* _UAPI_LINUX_STAT_H */
> diff --git a/samples/statx/test-statx.c b/samples/statx/test-statx.c
> index 38ef23c12e7d..86eac7d16c32 100644
> --- a/samples/statx/test-statx.c
> +++ b/samples/statx/test-statx.c
> @@ -134,6 +134,37 @@ static void dump_statx(struct statx *stx)
> if (stx->st_mask & STATX_GEN)
> printf("Inode gen : %xh\n", stx->st_gen);
>
> + if (stx->st_mask & STATX_WIN_ATTRS) {
> + unsigned char bits;
> + int loop, byte;
> +
> + static char wattr_representation[32 + 1] =
> + /* STATX_WIN_ATTR_ flags: */
> + "????????" /* 31-24 0x00000000-ff000000 */
> + "??????N?" /* 23-16 0x00000000-00ff0000 */
> + "ieNocrst" /* 15- 8 0x00000000-0000ff00 */
> + "n?Ad?SHR" /* 7- 0 0x00000000-000000ff */
> + ;
> +
> + printf("Win attrs : %08llx (",
> + (unsigned long long)stx->st_win_attrs);
> + for (byte = 32 - 8; byte >= 0; byte -= 8) {
> + bits = stx->st_win_attrs >> byte;
> + for (loop = 7; loop >= 0; loop--) {
> + int bit = byte + loop;
> +
> + if (bits & 0x80)
> + putchar(wattr_representation[31 - bit]);
> + else
> + putchar('-');
> + bits <<= 1;
> + }
> + if (byte)
> + putchar(' ');
> + }
> + printf(")\n");
> + }
> +
> if (stx->st_information) {
> unsigned char bits;
> int loop, byte;
>
> --
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Cheers, Andreas

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