CREATE with EXCLUSIVE mode on RHEL NFSv3 client(RHEL6 or RHEL7) creates unexpected uid, gid ownership file even though the original file is root:root (0:0) with HP-UX NFS server.

Issue

• CREATE with EXCLUSIVE mode on RHEL NFS client(RHEL6 or RHEL7) creates unexpected uid, gid ownership file even though the original file is root:root (0:0).

• For example, cp command in RHEL6 or later uses O_EXCL flag when the command creates or opens a file. Trying to copy a file belongs to root:root to a NFS share sometimes causes unexpected uid or/and gid.

  • NFS client's CREATE call.

    3160 Network File System, CREATE Call DH: 0xdaf6f3a0/test.log1 Mode: EXCLUSIVE
    3161     [Program Version: 3]
    3162     [V3 Procedure: CREATE (8)]
    3163     where
    3164         dir
    3165             length: 32
    3166             [hash (CRC-32): 0xdaf6f3a0]
    3167             filehandle: 40000003ffffffff000a000000000dde59a31b72000a0000...
    3168         Name: test.log1
    3169             length: 9
    3170             contents: test.log1
    3171             fill bytes: opaque data
    3172     Create Mode: EXCLUSIVE (2)
    3173     Verifier: Opaque Data
    

  • NFS server's CREATE reply

    3280 Network File System, CREATE Reply
    3281     [Program Version: 3]
    3282     [V3 Procedure: CREATE (8)]
    3283     Status: NFS3_OK (0)
    3284     obj
    3285         handle_follow: value follows (1)
    3286         handle
    3287             length: 32
    3288             [hash (CRC-32): 0xe9e31a36]
    3289             [Name: test.log1]
    3290             filehandle: 40000003ffffffff000a0000000012366793d09c000a0000...
    3291     obj_attributes  Regular File mode: 0000 uid: 0 gid: 912711000
    3292         attributes_follow: value follows (1)
    3293         attributes  Regular File mode: 0000 uid: 0 gid: 912711000
    3294             Type: Regular File (1)
    3295             Mode: 0
    3296                 .... .... .... .... .... 0... .... .... = S_ISUID: No
    3297                 .... .... .... .... .... .0.. .... .... = S_ISGID: No
    3298                 .... .... .... .... .... ..0. .... .... = S_ISVTX: No
    3299                 .... .... .... .... .... ...0 .... .... = S_IRUSR: No
    3300                 .... .... .... .... .... .... 0... .... = S_IWUSR: No
    3301                 .... .... .... .... .... .... .0.. .... = S_IXUSR: No
    3302                 .... .... .... .... .... .... ..0. .... = S_IRGRP: No
    3303                 .... .... .... .... .... .... ...0 .... = S_IWGRP: No
    3304                 .... .... .... .... .... .... .... 0... = S_IXGRP: No
    3305                 .... .... .... .... .... .... .... .0.. = S_IROTH: No
    3306                 .... .... .... .... .... .... .... ..0. = S_IWOTH: No
    3307                 .... .... .... .... .... .... .... ...0 = S_IXOTH: No
    3308             nlink: 1
    3309             uid: 0
    3310             gid: 912711000 <---- HERE