statx: add mount ID

Systemd is hacking around to get it and it's trivial to add to statx, so...

Cc: linux-api@vger.kernel.org
Cc: linux-man@vger.kernel.org
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

diff --git a/fs/stat.c b/fs/stat.c
index f7f07d1..3d88c99 100644 (file)
--- a/fs/stat.c
+++ b/fs/stat.c
@@ -22,6 +22,7 @@
 #include <asm/unistd.h>
 
 #include "internal.h"
+#include "mount.h"
 
 /**
  * generic_fillattr - Fill in the basic attributes from the inode struct
@@ -199,6 +200,8 @@ retry:
                goto out;
 
        error = vfs_getattr(&path, stat, request_mask, flags);
+       stat->mnt_id = real_mount(path.mnt)->mnt_id;
+       stat->result_mask |= STATX_MNT_ID;
        path_put(&path);
        if (retry_estale(error, lookup_flags)) {
                lookup_flags |= LOOKUP_REVAL;
@@ -563,6 +566,7 @@ cp_statx(const struct kstat *stat, struct statx __user *buffer)
        tmp.stx_rdev_minor = MINOR(stat->rdev);
        tmp.stx_dev_major = MAJOR(stat->dev);
        tmp.stx_dev_minor = MINOR(stat->dev);
+       tmp.stx_mnt_id = stat->mnt_id;
 
        return copy_to_user(buffer, &tmp, sizeof(tmp)) ? -EFAULT : 0;
 }

diff --git a/include/linux/stat.h b/include/linux/stat.h
index 528c4ba..56614af 100644 (file)
--- a/include/linux/stat.h
+++ b/include/linux/stat.h
@@ -47,6 +47,7 @@ struct kstat {
        struct timespec64 ctime;
        struct timespec64 btime;                        /* File creation time */
        u64             blocks;
+       u64             mnt_id;
 };
 
 #endif

diff --git a/include/uapi/linux/stat.h b/include/uapi/linux/stat.h
index d119278..d814562 100644 (file)
--- a/include/uapi/linux/stat.h
+++ b/include/uapi/linux/stat.h
@@ -123,7 +123,10 @@ struct statx {
        __u32   stx_dev_major;  /* ID of device containing file [uncond] */
        __u32   stx_dev_minor;
        /* 0x90 */
-       __u64   __spare2[14];   /* Spare space for future expansion */
+       __u64   stx_mnt_id;
+       __u64   __spare2;
+       /* 0xa0 */
+       __u64   __spare3[12];   /* Spare space for future expansion */
        /* 0x100 */
 };
 
@@ -148,6 +151,7 @@ struct statx {
 #define STATX_BLOCKS           0x00000400U     /* Want/got stx_blocks */
 #define STATX_BASIC_STATS      0x000007ffU     /* The stuff in the normal stat struct */
 #define STATX_BTIME            0x00000800U     /* Want/got stx_btime */
+#define STATX_MNT_ID           0x00001000U     /* Got stx_mnt_id */
 
 #define STATX__RESERVED                0x80000000U     /* Reserved for future struct statx expansion */