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Message-Id: <9F740B6B-F1F7-476A-9A49-58A2083E7C72@dilger.ca>
Date: Wed, 25 Apr 2012 09:44:59 -0500
From: Andreas Dilger <adilger@...ger.ca>
To: "J. Bruce Fields" <bfields@...ldses.org>
Cc: David Howells <dhowells@...hat.com>, linux-fsdevel@...r.kernel.org,
linux-nfs@...r.kernel.org, linux-cifs@...r.kernel.org,
samba-technical@...ts.samba.org, linux-ext4@...r.kernel.org,
wine-devel@...ehq.org, kfm-devel@....org, nautilus-list@...me.org,
linux-api@...r.kernel.org, libc-alpha@...rceware.org
Subject: Re: [PATCH 1/6] xstat: Add a pair of system calls to make extended file stats available
On 2012-04-24, at 4:29 PM, J. Bruce Fields wrote:
> On Thu, Apr 19, 2012 at 03:06:12PM +0100, David Howells wrote:
>> (11) Include granularity fields in the time data to indicate the
>> granularity of each of the times (NFSv4 time_delta) [Steve French].
>
> It looks like you're including this with *each* time? But surely
> there's no filesystem with different granularity (say) for ctime than
> for mtime. Also, nfsd will want only one time_delta, not one for each
> time.
I suspect the main reason for having a separate time_delta per timestamp
is to use the extra 32-bit field in the timestamp structs. Since those
structs have a 64-bit + 32-bit field, it would be messy to pack them,
and leaving the spare bytes unused and adding an additional field for
the granularity would just increase the struct size.
> Note also we need to document carefully what this means: I think it
> should be the granularity that the filesystem is capable of
> representing, but people are sometimes surprised to find out that the
> actual time source is usually more coarse-grained than that.
>
> --b.
>
>>
>> (12) FS_IOC_GETFLAGS value. These could be translated to BSD's st_flags.
>>
>> (13) Mask of features available on file (eg: ACLs, seclabel) [Brad Boyer,
>> Michael Kerrisk].
>>
>> (14) Spare space, request flags and information flags are provided for future
>> expansion.
>>
>>
>> The following structures are defined for the use of these new system calls:
>>
>> struct xstat_dev {
>> uint32_t major, minor;
>> };
>>
>> struct xstat_time {
>> uint64_t tv_sec;
>> uint32_t tv_nsec;
>> uint32_t tv_granularity;
>> };
>>
>> struct xstat {
>> uint32_t st_mask;
>> uint32_t st_mode;
>> uint32_t st_nlink;
>> uint32_t st_uid;
>> uint32_t st_gid;
>> uint32_t st_information;
>> uint32_t st_ioc_flags;
>> uint32_t st_blksize;
>> struct xstat_dev st_rdev;
>> struct xstat_dev st_dev;
>> struct xstat_time st_atime;
>> struct xstat_time st_btime;
>> struct xstat_time st_ctime;
>> struct xstat_time st_mtime;
>> uint64_t st_ino;
>> uint64_t st_size;
>> uint64_t st_blocks;
>> uint64_t st_gen;
>> uint64_t st_version;
>> uint8_t st_volume_id[16];
>> uint64_t __spares[11];
>> };
>>
>> where st_information is local system information about the file, st_btime is
>> the file creation time, st_gen is the inode generation (i_generation),
>> st_data_version is the data version number (i_version), st_ioc_flags is the
>> flags from FS_IOC_GETFLAGS, st_volume_id is where the volume identified is
>> stored, st_result_mask is a bitmask indicating the data provided and __spares[]
>> are where as-yet undefined fields can be placed.
>>
>> The defined bits in request_mask and st_mask are:
>>
>> XSTAT_MODE Want/got st_mode
>> XSTAT_NLINK Want/got st_nlink
>> XSTAT_UID Want/got st_uid
>> XSTAT_GID Want/got st_gid
>> XSTAT_RDEV Want/got st_rdev
>> XSTAT_ATIME Want/got st_atime
>> XSTAT_MTIME Want/got st_mtime
>> XSTAT_CTIME Want/got st_ctime
>> XSTAT_INO Want/got st_ino
>> XSTAT_SIZE Want/got st_size
>> XSTAT_BLOCKS Want/got st_blocks
>> XSTAT_BASIC_STATS [The stuff in the normal stat struct]
>> XSTAT_IOC_FLAGS Want/got FS_IOC_GETFLAGS
>> XSTAT_BTIME Want/got st_btime
>> XSTAT_GEN Want/got st_gen
>> XSTAT_VERSION Want/got st_data_version
>> XSTAT_VOLUME_ID Want/got st_volume_id
>> XSTAT_ALL_STATS [All currently available stuff]
>>
>> The defined bits in st_ioc_flags are the usual FS_xxx_FL, plus some extra flags
>> that might be supplied by the filesystem. Note that Ext4 returns flags outside
>> of {EXT4,FS}_FL_USER_VISIBLE in response to FS_IOC_GETFLAGS. Should
>> {EXT4,FS}_FL_USER_VISIBLE be extended to cover them? Or should the extra flags
>> be suppressed?
>>
>> The defined bits in the st_information field give local system data on a file,
>> how it is accessed, where it is and what it does:
>>
>> XSTAT_INFO_ENCRYPTED File is encrypted
>> XSTAT_INFO_TEMPORARY File is temporary (NTFS/CIFS/deleted)
>> XSTAT_INFO_FABRICATED File was made up by filesystem
>> XSTAT_INFO_KERNEL_API File is kernel API (eg: procfs/sysfs)
>> XSTAT_INFO_REMOTE File is remote
>> XSTAT_INFO_OFFLINE File is offline (CIFS)
>> XSTAT_INFO_AUTOMOUNT Dir is automount trigger
>> XSTAT_INFO_AUTODIR Dir provides unlisted automounts
>> XSTAT_INFO_NONSYSTEM_OWNERSHIP File has non-system ownership details
>> XSTAT_INFO_HAS_ACL File has an ACL of some sort
>> XSTAT_INFO_REPARSE_POINT File is reparse point (NTFS/CIFS)
>> XSTAT_INFO_HIDDEN File is marked hidden (DOS+)
>> XSTAT_INFO_SYSTEM File is marked system (DOS+)
>> XSTAT_INFO_ARCHIVE File is marked archive (DOS+)
>>
>> These are for the use of GUI tools that might want to mark files specially,
>> depending on what they are. I've tried not to provide overlap with
>> st_ioc_flags where something usable exists there. Should Hidden, System and
>> Archive flags be associated with ioc_flags, perhaps with ioc_flags extended to
>> 64-bits?
>>
>>
>> The system calls are:
>>
>> ssize_t ret = xstat(int dfd,
>> const char *filename,
>> unsigned int flags,
>> unsigned int mask,
>> struct xstat *buffer);
>>
>> ssize_t ret = fxstat(unsigned fd,
>> unsigned int flags,
>> unsigned int mask,
>> struct xstat *buffer);
>>
>>
>> The dfd, filename, flags and fd parameters indicate the file to query. There
>> is no equivalent of lstat() as that can be emulated with xstat() by passing
>> AT_SYMLINK_NOFOLLOW in flags.
>>
>> AT_FORCE_ATTR_SYNC can also be set in flags. This will require a network
>> filesystem to synchronise its attributes with the server.
>>
>> mask is a bitmask indicating the fields in struct xstat that are of interest to
>> the caller. The user should set this to XSTAT__BASIC_STATS to get the
>> basic set returned by stat().
>>
>> Should there just be one xstat() syscall that does fxstat() if filename is NULL?
>>
>> The fields in struct xstat come in a number of classes:
>>
>> (0) st_dev, st_blksize, st_information.
>>
>> These are local data and are always available.
>>
>> (1) st_mode, st_nlinks, st_uid, st_gid, st_[amc]time, st_ino, st_size,
>> st_blocks.
>>
>> These will be returned whether the caller asks for them or not. The
>> corresponding bits in result_mask will be set to indicate their presence.
>>
>> If the caller didn't ask for them, then they may be approximated. For
>> example, NFS won't waste any time updating them from the server, unless as
>> a byproduct of updating something requested.
>>
>> If the values don't actually exist for the underlying object (such as UID
>> or GID on a DOS file), then the bit won't be set in the result_mask, even
>> if the caller asked for the value and the returned value will be a
>> fabrication.
>>
>> (2) st_rdev.
>>
>> As for class (1), but this won't be returned if the file is not a blockdev
>> or chardev. The bit will be cleared if the value is not returned.
>>
>> (3) File creation time (st_btime), inode generation (st_gen), data version
>> (st_version), volume_id (st_volume_id) and inode flags (st_ioc_flags).
>>
>> These will be returned if available whether the caller asked for them or
>> not. The corresponding bits in result_mask will be set or cleared as
>> appropriate to indicate their presence.
>>
>> If the caller didn't ask for them, then they may be approximated. For
>> example, NFS won't waste any time updating them from the server, unless
>> as a byproduct of updating something requested.
>>
>> At the moment, this will only work on x86_64 and i386 as it requires system
>> calls to be wired up.
>>
>>
>> =======
>> TESTING
>> =======
>>
>> The following test program can be used to test the xstat system call:
>>
>> /* Test the xstat() system call
>> *
>> * Copyright (C) 2010 Red Hat, Inc. All Rights Reserved.
>> * Written by David Howells (dhowells@...hat.com)
>> *
>> * This program is free software; you can redistribute it and/or
>> * modify it under the terms of the GNU General Public Licence
>> * as published by the Free Software Foundation; either version
>> * 2 of the Licence, or (at your option) any later version.
>> */
>>
>> #define _GNU_SOURCE
>> #define _ATFILE_SOURCE
>> #include <stdio.h>
>> #include <stdlib.h>
>> #include <string.h>
>> #include <unistd.h>
>> #include <fcntl.h>
>> #include <time.h>
>> #include <sys/syscall.h>
>> #include <sys/stat.h>
>> #include <sys/types.h>
>>
>> #define AT_NO_AUTOMOUNT 0x800
>> #define AT_FORCE_ATTR_SYNC 0x2000
>>
>> #define XSTAT_MODE 0x00000001U
>> #define XSTAT_NLINK 0x00000002U
>> #define XSTAT_UID 0x00000004U
>> #define XSTAT_GID 0x00000008U
>> #define XSTAT_RDEV 0x00000010U
>> #define XSTAT_ATIME 0x00000020U
>> #define XSTAT_MTIME 0x00000040U
>> #define XSTAT_CTIME 0x00000080U
>> #define XSTAT_INO 0x00000100U
>> #define XSTAT_SIZE 0x00000200U
>> #define XSTAT_BLOCKS 0x00000400U
>> #define XSTAT_BASIC_STATS 0x000007ffU
>> #define XSTAT_BTIME 0x00000800U
>> #define XSTAT_GEN 0x00001000U
>> #define XSTAT_VERSION 0x00002000U
>> #define XSTAT_IOC_FLAGS 0x00004000U
>> #define XSTAT_VOLUME_ID 0x00008000U
>> #define XSTAT_ALL_STATS 0x0000ffffU
>>
>> struct xstat_dev {
>> uint32_t major;
>> uint32_t minor;
>> };
>>
>> struct xstat_time {
>> uint64_t tv_sec;
>> uint32_t tv_nsec;
>> uint32_t tv_granularity;
>> };
>>
>> struct xstat {
>> uint32_t st_mask;
>> uint32_t st_mode;
>> uint32_t st_nlink;
>> uint32_t st_uid;
>> uint32_t st_gid;
>> uint32_t st_information;
>> uint32_t st_ioc_flags;
>> uint32_t st_blksize;
>> struct xstat_dev st_rdev;
>> struct xstat_dev st_dev;
>> struct xstat_time st_atim;
>> struct xstat_time st_btim;
>> struct xstat_time st_ctim;
>> struct xstat_time st_mtim;
>> uint64_t st_ino;
>> uint64_t st_size;
>> uint64_t st_blksize;
>> uint64_t st_blocks;
>> uint64_t st_gen;
>> uint64_t st_version;
>> uint64_t st_volume_id[16];
>> uint64_t st_spares[11];
>> };
>>
>> #define XSTAT_INFO_ENCRYPTED 0x00000001U
>> #define XSTAT_INFO_TEMPORARY 0x00000002U
>> #define XSTAT_INFO_FABRICATED 0x00000004U
>> #define XSTAT_INFO_KERNEL_API 0x00000008U
>> #define XSTAT_INFO_REMOTE 0x00000010U
>> #define XSTAT_INFO_OFFLINE 0x00000020U
>> #define XSTAT_INFO_AUTOMOUNT 0x00000040U
>> #define XSTAT_INFO_AUTODIR 0x00000080U
>> #define XSTAT_INFO_NONSYSTEM_OWNERSHIP 0x00000100U
>> #define XSTAT_INFO_HAS_ACL 0x00000200U
>> #define XSTAT_INFO_REPARSE_POINT 0x00000400U
>> #define XSTAT_INFO_HIDDEN 0x00000800U
>> #define XSTAT_INFO_SYSTEM 0x00001000U
>> #define XSTAT_INFO_ARCHIVE 0x00002000U
>>
>> #define __NR_xstat 312
>> #define __NR_fxstat 313
>>
>> static __attribute__((unused))
>> ssize_t xstat(int dfd, const char *filename, unsigned flags,
>> unsigned int mask, struct xstat *buffer)
>> {
>> return syscall(__NR_xstat, dfd, filename, flags, mask, buffer);
>> }
>>
>> static __attribute__((unused))
>> ssize_t fxstat(int fd, unsigned flags,
>> unsigned int mask, struct xstat *buffer)
>> {
>> return syscall(__NR_fxstat, fd, flags, mask, buffer);
>> }
>>
>> static void print_time(const char *field, const struct xstat_time *xstm)
>> {
>> struct tm tm;
>> time_t tim;
>> char buffer[100];
>> int len;
>>
>> tim = xstm->tv_sec;
>> if (!localtime_r(&tim, &tm)) {
>> perror("localtime_r");
>> exit(1);
>> }
>> len = strftime(buffer, 100, "%F %T", &tm);
>> if (len == 0) {
>> perror("strftime");
>> exit(1);
>> }
>> printf("%s", field);
>> fwrite(buffer, 1, len, stdout);
>> printf(".%09u", xstm->tv_nsec);
>> len = strftime(buffer, 100, "%z", &tm);
>> if (len == 0) {
>> perror("strftime2");
>> exit(1);
>> }
>> fwrite(buffer, 1, len, stdout);
>> printf("\n");
>> }
>>
>> static void dump_xstat(struct xstat *xst)
>> {
>> char buffer[256], ft;
>>
>> printf("results=%x\n", xst->st_mask);
>>
>> printf(" ");
>> if (xst->st_mask & XSTAT_SIZE)
>> printf(" Size: %-15llu", (unsigned long long) xst->st_size);
>> if (xst->st_mask & XSTAT_BLOCKS)
>> printf(" Blocks: %-10llu", (unsigned long long) xst->st_blocks);
>> printf(" IO Block: %-6llu ", (unsigned long long) xst->st_blksize);
>> if (xst->st_mask & XSTAT_MODE) {
>> switch (xst->st_mode & S_IFMT) {
>> case S_IFIFO: printf(" FIFO\n"); ft = 'p'; break;
>> case S_IFCHR: printf(" character special file\n"); ft = 'c'; break;
>> case S_IFDIR: printf(" directory\n"); ft = 'd'; break;
>> case S_IFBLK: printf(" block special file\n"); ft = 'b'; break;
>> case S_IFREG: printf(" regular file\n"); ft = '-'; break;
>> case S_IFLNK: printf(" symbolic link\n"); ft = 'l'; break;
>> case S_IFSOCK: printf(" socket\n"); ft = 's'; break;
>> default:
>> printf("unknown type (%o)\n", xst->st_mode & S_IFMT);
>> ft = '?';
>> break;
>> }
>> }
>>
>> sprintf(buffer, "%02x:%02x", xst->st_dev.major, xst->st_dev.minor);
>> printf("Device: %-15s", buffer);
>> if (xst->st_mask & XSTAT_INO)
>> printf(" Inode: %-11llu", (unsigned long long) xst->st_ino);
>> if (xst->st_mask & XSTAT_SIZE)
>> printf(" Links: %-5u", xst->st_nlink);
>> if (xst->st_mask & XSTAT_RDEV)
>> printf(" Device type: %u,%u",
>> xst->st_rdev.major, xst->st_rdev.minor);
>> printf("\n");
>>
>> if (xst->st_mask & XSTAT_MODE)
>> printf("Access: (%04o/%c%c%c%c%c%c%c%c%c%c) ",
>> xst->st_mode & 07777,
>> ft,
>> xst->st_mode & S_IRUSR ? 'r' : '-',
>> xst->st_mode & S_IWUSR ? 'w' : '-',
>> xst->st_mode & S_IXUSR ? 'x' : '-',
>> xst->st_mode & S_IRGRP ? 'r' : '-',
>> xst->st_mode & S_IWGRP ? 'w' : '-',
>> xst->st_mode & S_IXGRP ? 'x' : '-',
>> xst->st_mode & S_IROTH ? 'r' : '-',
>> xst->st_mode & S_IWOTH ? 'w' : '-',
>> xst->st_mode & S_IXOTH ? 'x' : '-');
>> if (xst->st_mask & XSTAT_UID)
>> printf("Uid: %d \n", xst->st_uid);
>> if (xst->st_mask & XSTAT_GID)
>> printf("Gid: %u\n", xst->st_gid);
>>
>> if (xst->st_mask & XSTAT_ATIME)
>> print_time("Access: ", &xst->st_atim);
>> if (xst->st_mask & XSTAT_MTIME)
>> print_time("Modify: ", &xst->st_mtim);
>> if (xst->st_mask & XSTAT_CTIME)
>> print_time("Change: ", &xst->st_ctim);
>> if (xst->st_mask & XSTAT_BTIME)
>> print_time("Create: ", &xst->st_btim);
>>
>> if (xst->st_mask & XSTAT_GEN)
>> printf("Inode version: %llxh\n", (unsigned long long) xst->st_gen);
>> if (xst->st_mask & XSTAT_VERSION)
>> printf("Data version: %llxh\n", (unsigned long long) xst->st_version);
>>
>> if (xst->st_mask & XSTAT_IOC_FLAGS) {
>> unsigned char bits;
>> int loop, byte;
>>
>> static char flag_representation[32 + 1] =
>> /* FS_IOC_GETFLAGS flags: */
>> "????????" /* 31-24 0x00000000-ff000000 */
>> "????ehTD" /* 23-16 0x00000000-00ff0000 */
>> "tj?IE?XZ" /* 15- 8 0x00000000-0000ff00 */
>> "AdaiScus" /* 7- 0 0x00000000-000000ff */
>> ;
>>
>> printf("Inode flags: %08x (", xst->st_ioc_flags);
>> for (byte = 32 - 8; byte >= 0; byte -= 8) {
>> bits = xst->st_ioc_flags >> byte;
>> for (loop = 7; loop >= 0; loop--) {
>> int bit = byte + loop;
>>
>> if (bits & 0x80)
>> putchar(flag_representation[31 - bit]);
>> else
>> putchar('-');
>> bits <<= 1;
>> }
>> if (byte)
>> putchar(' ');
>> }
>> printf(")\n");
>> }
>>
>> if (xst->st_information) {
>> unsigned char bits;
>> int loop, byte;
>>
>> static char info_representation[32 + 1] =
>> /* XSTAT_INFO_ flags: */
>> "????????" /* 31-24 0x00000000-ff000000 */
>> "????????" /* 23-16 0x00000000-00ff0000 */
>> "??ASHRan" /* 15- 8 0x00000000-0000ff00 */
>> "dmorkfte" /* 7- 0 0x00000000-000000ff */
>> ;
>>
>> printf("Information: %08x (", xst->st_information);
>> for (byte = 32 - 8; byte >= 0; byte -= 8) {
>> bits = xst->st_information >> byte;
>> for (loop = 7; loop >= 0; loop--) {
>> int bit = byte + loop;
>>
>> if (bits & 0x80)
>> putchar(info_representation[31 - bit]);
>> else
>> putchar('-');
>> bits <<= 1;
>> }
>> if (byte)
>> putchar(' ');
>> }
>> printf(")\n");
>> }
>>
>> if (xst->st_mask & XSTAT_VOLUME_ID) {
>> int loop;
>> printf("Volume ID: ");
>> for (loop = 0; loop < sizeof(xst->st_volume_id); loop++) {
>> printf("%02x", xst->st_volume_id[loop]);
>> if (loop == 7)
>> printf("-");
>> }
>> printf("\n");
>> }
>> }
>>
>> void dump_hex(unsigned long long *data, int from, int to)
>> {
>> unsigned offset, print_offset = 1, col = 0;
>>
>> from /= 8;
>> to = (to + 7) / 8;
>>
>> for (offset = from; offset < to; offset++) {
>> if (print_offset) {
>> printf("%04x: ", offset * 8);
>> print_offset = 0;
>> }
>> printf("%016llx", data[offset]);
>> col++;
>> if ((col & 3) == 0) {
>> printf("\n");
>> print_offset = 1;
>> } else {
>> printf(" ");
>> }
>> }
>>
>> if (!print_offset)
>> printf("\n");
>> }
>>
>> int main(int argc, char **argv)
>> {
>> struct xstat xst;
>> int ret, raw = 0, atflag = AT_SYMLINK_NOFOLLOW;
>>
>> unsigned int mask = XSTAT_ALL_STATS;
>>
>> for (argv++; *argv; argv++) {
>> if (strcmp(*argv, "-F") == 0) {
>> atflag |= AT_FORCE_ATTR_SYNC;
>> continue;
>> }
>> if (strcmp(*argv, "-L") == 0) {
>> atflag &= ~AT_SYMLINK_NOFOLLOW;
>> continue;
>> }
>> if (strcmp(*argv, "-O") == 0) {
>> mask &= ~XSTAT_BASIC_STATS;
>> continue;
>> }
>> if (strcmp(*argv, "-A") == 0) {
>> atflag |= AT_NO_AUTOMOUNT;
>> continue;
>> }
>> if (strcmp(*argv, "-R") == 0) {
>> raw = 1;
>> continue;
>> }
>>
>> memset(&xst, 0xbf, sizeof(xst));
>> ret = xstat(AT_FDCWD, *argv, atflag, mask, &xst);
>> printf("xstat(%s) = %d\n", *argv, ret);
>> if (ret < 0) {
>> perror(*argv);
>> exit(1);
>> }
>>
>> if (raw)
>> dump_hex((unsigned long long *)&xst, 0, sizeof(xst));
>>
>> dump_xstat(&xst);
>> }
>> return 0;
>> }
>>
>> Just compile and run, passing it paths to the files you want to examine:
>>
>> [root@...romeda ~]# /tmp/xstat /proc/$$
>> xstat(/proc/2074) = 160
>> results=47ef
>> Size: 0 Blocks: 0 IO Block: 1024 directory
>> Device: 00:03 Inode: 9072 Links: 7
>> Access: (0555/dr-xr-xr-x) Uid: 0
>> Gid: 0
>> Access: 2010-07-14 16:50:46.609336272+0100
>> Modify: 2010-07-14 16:50:46.609336272+0100
>> Change: 2010-07-14 16:50:46.609336272+0100
>> Inode flags: 0000000100000000 (-------- -------- -------- -------S -------- -------- -------- --------)
>> [root@...romeda ~]# /tmp/xstat /afs/archive/linuxdev/fedora9/x86_64/kernel-devel-2.6.25.10-86.fc9.x86_64.rpm
>> xstat(/afs/archive/linuxdev/fedora9/x86_64/kernel-devel-2.6.25.10-86.fc9.x86_64.rpm) = 160
>> results=77ef
>> Size: 5413882 Blocks: 0 IO Block: 4096 regular file
>> Device: 00:15 Inode: 2288 Links: 1
>> Access: (0644/-rw-r--r--) Uid: 75338
>> Gid: 0
>> Access: 2008-11-05 19:47:22.000000000+0000
>> Modify: 2008-11-05 19:47:22.000000000+0000
>> Change: 2008-11-05 19:47:22.000000000+0000
>> Inode version: 795h
>> Data version: 2h
>> Inode flags: 0000000800000000 (-------- -------- -------- ----r--- -------- -------- -------- --------)
>>
>> Signed-off-by: David Howells <dhowells@...hat.com>
>> ---
>>
>> arch/x86/syscalls/syscall_32.tbl | 2
>> arch/x86/syscalls/syscall_64.tbl | 2
>> fs/stat.c | 350 +++++++++++++++++++++++++++++++++++---
>> include/linux/fcntl.h | 1
>> include/linux/fs.h | 4
>> include/linux/stat.h | 126 +++++++++++++-
>> include/linux/syscalls.h | 7 +
>> 7 files changed, 461 insertions(+), 31 deletions(-)
>>
>> diff --git a/arch/x86/syscalls/syscall_32.tbl b/arch/x86/syscalls/syscall_32.tbl
>> index 29f9f05..980eb5a 100644
>> --- a/arch/x86/syscalls/syscall_32.tbl
>> +++ b/arch/x86/syscalls/syscall_32.tbl
>> @@ -355,3 +355,5 @@
>> 346 i386 setns sys_setns
>> 347 i386 process_vm_readv sys_process_vm_readv compat_sys_process_vm_readv
>> 348 i386 process_vm_writev sys_process_vm_writev compat_sys_process_vm_writev
>> +349 i386 xstat sys_xstat
>> +350 i386 fxstat sys_fxstat
>> diff --git a/arch/x86/syscalls/syscall_64.tbl b/arch/x86/syscalls/syscall_64.tbl
>> index dd29a9e..7ae24bb 100644
>> --- a/arch/x86/syscalls/syscall_64.tbl
>> +++ b/arch/x86/syscalls/syscall_64.tbl
>> @@ -318,6 +318,8 @@
>> 309 common getcpu sys_getcpu
>> 310 64 process_vm_readv sys_process_vm_readv
>> 311 64 process_vm_writev sys_process_vm_writev
>> +312 common xstat sys_xstat
>> +313 common fxstat sys_fxstat
>> #
>> # x32-specific system call numbers start at 512 to avoid cache impact
>> # for native 64-bit operation.
>> diff --git a/fs/stat.c b/fs/stat.c
>> index c733dc5..af3ef33 100644
>> --- a/fs/stat.c
>> +++ b/fs/stat.c
>> @@ -18,8 +18,20 @@
>> #include <asm/uaccess.h>
>> #include <asm/unistd.h>
>>
>> +/**
>> + * generic_fillattr - Fill in the basic attributes from the inode struct
>> + * @inode: Inode to use as the source
>> + * @stat: Where to fill in the attributes
>> + *
>> + * Fill in the basic attributes in the kstat structure from data that's to be
>> + * found on the VFS inode structure. This is the default if no getattr inode
>> + * operation is supplied.
>> + */
>> void generic_fillattr(struct inode *inode, struct kstat *stat)
>> {
>> + struct super_block *sb = inode->i_sb;
>> + u32 x;
>> +
>> stat->dev = inode->i_sb->s_dev;
>> stat->ino = inode->i_ino;
>> stat->mode = inode->i_mode;
>> @@ -27,17 +39,61 @@ void generic_fillattr(struct inode *inode, struct kstat *stat)
>> stat->uid = inode->i_uid;
>> stat->gid = inode->i_gid;
>> stat->rdev = inode->i_rdev;
>> - stat->size = i_size_read(inode);
>> - stat->atime = inode->i_atime;
>> stat->mtime = inode->i_mtime;
>> stat->ctime = inode->i_ctime;
>> - stat->blksize = (1 << inode->i_blkbits);
>> + stat->size = i_size_read(inode);
>> stat->blocks = inode->i_blocks;
>> -}
>> + stat->blksize = (1 << inode->i_blkbits);
>>
>> + stat->result_mask |= XSTAT_BASIC_STATS & ~XSTAT_RDEV;
>> + if (IS_NOATIME(inode))
>> + stat->result_mask &= ~XSTAT_ATIME;
>> + else
>> + stat->atime = inode->i_atime;
>> +
>> + if (S_ISREG(stat->mode) && stat->nlink == 0)
>> + stat->information |= XSTAT_INFO_TEMPORARY;
>> + if (IS_AUTOMOUNT(inode))
>> + stat->information |= XSTAT_INFO_AUTOMOUNT;
>> + if (IS_POSIXACL(inode))
>> + stat->information |= XSTAT_INFO_HAS_ACL;
>> +
>> + /* if unset, assume 1s granularity */
>> + stat->tv_granularity = sb->s_time_gran ?: 1000000000U;
>> +
>> + if (unlikely(S_ISBLK(stat->mode) || S_ISCHR(stat->mode)))
>> + stat->result_mask |= XSTAT_RDEV;
>> +
>> + x = ((u32*)&stat->volume_id)[0] = ((u32*)&sb->s_volume_id)[0];
>> + x |= ((u32*)&stat->volume_id)[1] = ((u32*)&sb->s_volume_id)[1];
>> + x |= ((u32*)&stat->volume_id)[2] = ((u32*)&sb->s_volume_id)[2];
>> + x |= ((u32*)&stat->volume_id)[3] = ((u32*)&sb->s_volume_id)[3];
>> + if (x)
>> + stat->result_mask |= XSTAT_VOLUME_ID;
>> +}
>> EXPORT_SYMBOL(generic_fillattr);
>>
>> -int vfs_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
>> +/**
>> + * vfs_xgetattr - Get the basic and extra attributes of a file
>> + * @mnt: The mountpoint to which the dentry belongs
>> + * @dentry: The file of interest
>> + * @stat: Where to return the statistics
>> + *
>> + * Ask the filesystem for a file's attributes. The caller must have preset
>> + * stat->request_mask and stat->query_flags to indicate what they want.
>> + *
>> + * If the file is remote, the filesystem can be forced to update the attributes
>> + * from the backing store by passing AT_FORCE_ATTR_SYNC in query_flags.
>> + *
>> + * Bits must have been set in stat->request_mask to indicate which attributes
>> + * the caller wants retrieving. Any such attribute not requested may be
>> + * returned anyway, but the value may be approximate, and, if remote, may not
>> + * have been synchronised with the server.
>> + *
>> + * 0 will be returned on success, and a -ve error code if unsuccessful.
>> + */
>> +int vfs_xgetattr(struct vfsmount *mnt, struct dentry *dentry,
>> + struct kstat *stat)
>> {
>> struct inode *inode = dentry->d_inode;
>> int retval;
>> @@ -46,64 +102,184 @@ int vfs_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
>> if (retval)
>> return retval;
>>
>> + stat->result_mask = 0;
>> + stat->information = 0;
>> + stat->ioc_flags = 0;
>> if (inode->i_op->getattr)
>> return inode->i_op->getattr(mnt, dentry, stat);
>>
>> generic_fillattr(inode, stat);
>> return 0;
>> }
>> +EXPORT_SYMBOL(vfs_xgetattr);
>>
>> +/**
>> + * vfs_getattr - Get the basic attributes of a file
>> + * @mnt: The mountpoint to which the dentry belongs
>> + * @dentry: The file of interest
>> + * @stat: Where to return the statistics
>> + *
>> + * Ask the filesystem for a file's attributes. If remote, the filesystem isn't
>> + * forced to update its files from the backing store. Only the basic set of
>> + * attributes will be retrieved; anyone wanting more must use vfs_getxattr(),
>> + * as must anyone who wants to force attributes to be sync'd with the server.
>> + *
>> + * 0 will be returned on success, and a -ve error code if unsuccessful.
>> + */
>> +int vfs_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
>> +{
>> + stat->query_flags = 0;
>> + stat->request_mask = XSTAT_BASIC_STATS;
>> + return vfs_xgetattr(mnt, dentry, stat);
>> +}
>> EXPORT_SYMBOL(vfs_getattr);
>>
>> -int vfs_fstat(unsigned int fd, struct kstat *stat)
>> +/**
>> + * vfs_fxstat - Get basic and extra attributes by file descriptor
>> + * @fd: The file descriptor refering to the file of interest
>> + * @stat: The result structure to fill in.
>> + *
>> + * This function is a wrapper around vfs_xgetattr(). The main difference is
>> + * that it uses a file descriptor to determine the file location.
>> + *
>> + * The caller must have preset stat->query_flags and stat->request_mask as for
>> + * vfs_xgetattr().
>> + *
>> + * 0 will be returned on success, and a -ve error code if unsuccessful.
>> + */
>> +int vfs_fxstat(unsigned int fd, struct kstat *stat)
>> {
>> struct file *f = fget(fd);
>> int error = -EBADF;
>>
>> + if (stat->query_flags & ~KSTAT_QUERY_FLAGS)
>> + return -EINVAL;
>> if (f) {
>> - error = vfs_getattr(f->f_path.mnt, f->f_path.dentry, stat);
>> + error = vfs_xgetattr(f->f_path.mnt, f->f_path.dentry, stat);
>> fput(f);
>> }
>> return error;
>> }
>> +EXPORT_SYMBOL(vfs_fxstat);
>> +
>> +/**
>> + * vfs_fstat - Get basic attributes by file descriptor
>> + * @fd: The file descriptor refering to the file of interest
>> + * @stat: The result structure to fill in.
>> + *
>> + * This function is a wrapper around vfs_getattr(). The main difference is
>> + * that it uses a file descriptor to determine the file location.
>> + *
>> + * 0 will be returned on success, and a -ve error code if unsuccessful.
>> + */
>> +int vfs_fstat(unsigned int fd, struct kstat *stat)
>> +{
>> + stat->query_flags = 0;
>> + stat->request_mask = XSTAT_BASIC_STATS;
>> + return vfs_fxstat(fd, stat);
>> +}
>> EXPORT_SYMBOL(vfs_fstat);
>>
>> -int vfs_fstatat(int dfd, const char __user *filename, struct kstat *stat,
>> - int flag)
>> +/**
>> + * vfs_xstat - Get basic and extra attributes by filename
>> + * @dfd: A file descriptor representing the base dir for a relative filename
>> + * @filename: The name of the file of interest
>> + * @flags: Flags to control the query
>> + * @stat: The result structure to fill in.
>> + *
>> + * This function is a wrapper around vfs_xgetattr(). The main difference is
>> + * that it uses a filename and base directory to determine the file location.
>> + * Additionally, the addition of AT_SYMLINK_NOFOLLOW to flags will prevent a
>> + * symlink at the given name from being referenced.
>> + *
>> + * The caller must have preset stat->request_mask as for vfs_xgetattr(). The
>> + * flags are also used to load up stat->query_flags.
>> + *
>> + * 0 will be returned on success, and a -ve error code if unsuccessful.
>> + */
>> +int vfs_xstat(int dfd, const char __user *filename, int flags,
>> + struct kstat *stat)
>> {
>> struct path path;
>> - int error = -EINVAL;
>> - int lookup_flags = 0;
>> + int error, lookup_flags = LOOKUP_FOLLOW | LOOKUP_AUTOMOUNT;
>>
>> - if ((flag & ~(AT_SYMLINK_NOFOLLOW | AT_NO_AUTOMOUNT |
>> - AT_EMPTY_PATH)) != 0)
>> - goto out;
>> + if ((flags & ~(AT_SYMLINK_NOFOLLOW | AT_NO_AUTOMOUNT |
>> + AT_EMPTY_PATH | KSTAT_QUERY_FLAGS)) != 0)
>> + return -EINVAL;
>>
>> - if (!(flag & AT_SYMLINK_NOFOLLOW))
>> - lookup_flags |= LOOKUP_FOLLOW;
>> - if (flag & AT_EMPTY_PATH)
>> + if (flags & AT_SYMLINK_NOFOLLOW)
>> + lookup_flags &= ~LOOKUP_FOLLOW;
>> + if (flags & AT_NO_AUTOMOUNT)
>> + lookup_flags &= ~LOOKUP_AUTOMOUNT;
>> + if (flags & AT_EMPTY_PATH)
>> lookup_flags |= LOOKUP_EMPTY;
>>
>> + stat->query_flags = flags & KSTAT_QUERY_FLAGS;
>> error = user_path_at(dfd, filename, lookup_flags, &path);
>> - if (error)
>> - goto out;
>> -
>> - error = vfs_getattr(path.mnt, path.dentry, stat);
>> - path_put(&path);
>> -out:
>> + if (!error) {
>> + error = vfs_xgetattr(path.mnt, path.dentry, stat);
>> + path_put(&path);
>> + }
>> return error;
>> }
>> +EXPORT_SYMBOL(vfs_xstat);
>> +
>> +/**
>> + * vfs_fstatat - Get basic attributes by filename
>> + * @dfd: A file descriptor representing the base dir for a relative filename
>> + * @filename: The name of the file of interest
>> + * @flags: Flags to control the query
>> + * @stat: The result structure to fill in.
>> + *
>> + * This function is a wrapper around vfs_xstat(). The difference is that it
>> + * preselects basic stats only. The flags are used to load up
>> + * stat->query_flags in addition to indicating symlink handling during path
>> + * resolution.
>> + *
>> + * 0 will be returned on success, and a -ve error code if unsuccessful.
>> + */
>> +int vfs_fstatat(int dfd, const char __user *filename, struct kstat *stat,
>> + int flags)
>> +{
>> + stat->request_mask = XSTAT_BASIC_STATS;
>> + return vfs_xstat(dfd, filename, flags, stat);
>> +}
>> EXPORT_SYMBOL(vfs_fstatat);
>>
>> -int vfs_stat(const char __user *name, struct kstat *stat)
>> +/**
>> + * vfs_stat - Get basic attributes by filename
>> + * @filename: The name of the file of interest
>> + * @stat: The result structure to fill in.
>> + *
>> + * This function is a wrapper around vfs_xstat(). The difference is that it
>> + * preselects basic stats only, terminal symlinks are followed regardless and a
>> + * remote filesystem can't be forced to query the server. If such is desired,
>> + * vfs_xstat() should be used instead.
>> + *
>> + * 0 will be returned on success, and a -ve error code if unsuccessful.
>> + */
>> +int vfs_stat(const char __user *filename, struct kstat *stat)
>> {
>> - return vfs_fstatat(AT_FDCWD, name, stat, 0);
>> + stat->request_mask = XSTAT_BASIC_STATS;
>> + return vfs_xstat(AT_FDCWD, filename, 0, stat);
>> }
>> EXPORT_SYMBOL(vfs_stat);
>>
>> +/**
>> + * vfs_stat - Get basic attributes by filename, without following terminal symlink
>> + * @filename: The name of the file of interest
>> + * @stat: The result structure to fill in.
>> + *
>> + * This function is a wrapper around vfs_xstat(). The difference is that it
>> + * preselects basic stats only, terminal symlinks are note followed regardless
>> + * and a remote filesystem can't be forced to query the server. If such is
>> + * desired, vfs_xstat() should be used instead.
>> + *
>> + * 0 will be returned on success, and a -ve error code if unsuccessful.
>> + */
>> int vfs_lstat(const char __user *name, struct kstat *stat)
>> {
>> - return vfs_fstatat(AT_FDCWD, name, stat, AT_SYMLINK_NOFOLLOW);
>> + return vfs_xstat(AT_FDCWD, name, AT_SYMLINK_NOFOLLOW, stat);
>> }
>> EXPORT_SYMBOL(vfs_lstat);
>>
>> @@ -118,7 +294,7 @@ static int cp_old_stat(struct kstat *stat, struct __old_kernel_stat __user * sta
>> {
>> static int warncount = 5;
>> struct __old_kernel_stat tmp;
>> -
>> +
>> if (warncount > 0) {
>> warncount--;
>> printk(KERN_WARNING "VFS: Warning: %s using old stat() call. Recompile your binary.\n",
>> @@ -143,7 +319,7 @@ static int cp_old_stat(struct kstat *stat, struct __old_kernel_stat __user * sta
>> #if BITS_PER_LONG == 32
>> if (stat->size > MAX_NON_LFS)
>> return -EOVERFLOW;
>> -#endif
>> +#endif
>> tmp.st_size = stat->size;
>> tmp.st_atime = stat->atime.tv_sec;
>> tmp.st_mtime = stat->mtime.tv_sec;
>> @@ -225,7 +401,7 @@ static int cp_new_stat(struct kstat *stat, struct stat __user *statbuf)
>> #if BITS_PER_LONG == 32
>> if (stat->size > MAX_NON_LFS)
>> return -EOVERFLOW;
>> -#endif
>> +#endif
>> tmp.st_size = stat->size;
>> tmp.st_atime = stat->atime.tv_sec;
>> tmp.st_mtime = stat->mtime.tv_sec;
>> @@ -412,6 +588,122 @@ SYSCALL_DEFINE4(fstatat64, int, dfd, const char __user *, filename,
>> }
>> #endif /* __ARCH_WANT_STAT64 */
>>
>> +/*
>> + * Get the xstat parameters if supplied
>> + */
>> +static int xstat_get_params(unsigned int mask, struct xstat __user *buffer,
>> + struct kstat *stat)
>> +{
>> + memset(stat, 0xde, sizeof(*stat)); // DEBUGGING
>> +
>> + if (!access_ok(VERIFY_WRITE, buffer, sizeof(*buffer)))
>> + return -EFAULT;
>> +
>> + stat->request_mask = mask & XSTAT_ALL_STATS;
>> + stat->result_mask = 0;
>> + return 0;
>> +}
>> +
>> +/*
>> + * Set the xstat results.
>> + *
>> + * If the buffer size was 0, we just return the size of the buffer needed to
>> + * return the full result.
>> + *
>> + * If bufsize indicates a buffer of insufficient size to hold the full result,
>> + * we return -E2BIG.
>> + *
>> + * Otherwise we copy the extended stats to userspace and return the amount of
>> + * data written into the buffer (or -EFAULT).
>> + */
>> +static long xstat_set_result(struct kstat *stat, struct xstat __user *buffer)
>> +{
>> + u32 mask = stat->result_mask, gran = stat->tv_granularity;
>> +
>> +#define __put_timestamp(kts, uts) ( \
>> + __put_user(kts.tv_sec, uts.tv_sec ) || \
>> + __put_user(kts.tv_nsec, uts.tv_nsec ) || \
>> + __put_user(gran, uts.tv_granularity ))
>> +
>> + /* clear out anything we're not returning */
>> + if (!(mask & XSTAT_IOC_FLAGS))
>> + stat->ioc_flags = 0;
>> + if (!(mask & XSTAT_BTIME))
>> + memset(&stat->btime, 0, sizeof(stat->btime));
>> + if (!(mask & XSTAT_GEN))
>> + stat->gen = 0;
>> + if (!(mask & XSTAT_VERSION))
>> + stat->version = 0;
>> + if (!(mask & XSTAT_VOLUME_ID))
>> + memset(&stat->volume_id, 0, sizeof(stat->volume_id));
>> +
>> + /* transfer the results */
>> + if (__put_user(mask, &buffer->st_mask ) ||
>> + __put_user(stat->mode, &buffer->st_mode ) ||
>> + __put_user(stat->nlink, &buffer->st_nlink ) ||
>> + __put_user(stat->uid, &buffer->st_uid ) ||
>> + __put_user(stat->gid, &buffer->st_gid ) ||
>> + __put_user(stat->information, &buffer->st_information ) ||
>> + __put_user(stat->ioc_flags, &buffer->st_ioc_flags ) ||
>> + __put_user(stat->blksize, &buffer->st_blksize ) ||
>> + __put_user(MAJOR(stat->rdev), &buffer->st_rdev.major ) ||
>> + __put_user(MINOR(stat->rdev), &buffer->st_rdev.minor ) ||
>> + __put_user(MAJOR(stat->dev), &buffer->st_dev.major ) ||
>> + __put_user(MINOR(stat->dev), &buffer->st_dev.minor ) ||
>> + __put_timestamp(stat->atime, &buffer->st_atime ) ||
>> + __put_timestamp(stat->btime, &buffer->st_btime ) ||
>> + __put_timestamp(stat->ctime, &buffer->st_ctime ) ||
>> + __put_timestamp(stat->mtime, &buffer->st_mtime ) ||
>> + __put_user(stat->ino, &buffer->st_ino ) ||
>> + __put_user(stat->size, &buffer->st_size ) ||
>> + __put_user(stat->blocks, &buffer->st_blocks ) ||
>> + __put_user(stat->gen, &buffer->st_gen ) ||
>> + __put_user(stat->version, &buffer->st_version ) ||
>> + __copy_to_user(&buffer->st_volume_id, &stat->volume_id,
>> + sizeof(buffer->st_volume_id) ) ||
>> + __clear_user(&buffer->__spares, sizeof(buffer->__spares)))
>> + return -EFAULT;
>> + return 0;
>> +}
>> +
>> +/*
>> + * System call to get extended stats by path
>> + */
>> +SYSCALL_DEFINE5(xstat,
>> + int, dfd, const char __user *, filename, unsigned, flags,
>> + unsigned int, mask, struct xstat __user *, buffer)
>> +{
>> + struct kstat stat;
>> + int error;
>> +
>> + error = xstat_get_params(mask, buffer, &stat);
>> + if (error != 0)
>> + return error;
>> + error = vfs_xstat(dfd, filename, flags, &stat);
>> + if (error)
>> + return error;
>> + return xstat_set_result(&stat, buffer);
>> +}
>> +
>> +/*
>> + * System call to get extended stats by file descriptor
>> + */
>> +SYSCALL_DEFINE4(fxstat, unsigned int, fd, unsigned int, flags,
>> + unsigned int, mask, struct xstat __user *, buffer)
>> +{
>> + struct kstat stat;
>> + int error;
>> +
>> + error = xstat_get_params(mask, buffer, &stat);
>> + if (error < 0)
>> + return error;
>> + stat.query_flags = flags;
>> + error = vfs_fxstat(fd, &stat);
>> + if (error)
>> + return error;
>> + return xstat_set_result(&stat, buffer);
>> +}
>> +
>> /* Caller is here responsible for sufficient locking (ie. inode->i_lock) */
>> void __inode_add_bytes(struct inode *inode, loff_t bytes)
>> {
>> diff --git a/include/linux/fcntl.h b/include/linux/fcntl.h
>> index f550f89..faa9e5d 100644
>> --- a/include/linux/fcntl.h
>> +++ b/include/linux/fcntl.h
>> @@ -47,6 +47,7 @@
>> #define AT_SYMLINK_FOLLOW 0x400 /* Follow symbolic links. */
>> #define AT_NO_AUTOMOUNT 0x800 /* Suppress terminal automount traversal */
>> #define AT_EMPTY_PATH 0x1000 /* Allow empty relative pathname */
>> +#define AT_FORCE_ATTR_SYNC 0x2000 /* Force the attributes to be sync'd with the server */
>>
>> #ifdef __KERNEL__
>>
>> diff --git a/include/linux/fs.h b/include/linux/fs.h
>> index 8de6755..ec6c62e 100644
>> --- a/include/linux/fs.h
>> +++ b/include/linux/fs.h
>> @@ -1467,6 +1467,7 @@ struct super_block {
>>
>> char s_id[32]; /* Informational name */
>> u8 s_uuid[16]; /* UUID */
>> + unsigned char s_volume_id[16]; /* Volume identifier */
>>
>> void *s_fs_info; /* Filesystem private info */
>> unsigned int s_max_links;
>> @@ -2470,6 +2471,7 @@ extern const struct inode_operations page_symlink_inode_operations;
>> extern int generic_readlink(struct dentry *, char __user *, int);
>> extern void generic_fillattr(struct inode *, struct kstat *);
>> extern int vfs_getattr(struct vfsmount *, struct dentry *, struct kstat *);
>> +extern int vfs_xgetattr(struct vfsmount *, struct dentry *, struct kstat *);
>> void __inode_add_bytes(struct inode *inode, loff_t bytes);
>> void inode_add_bytes(struct inode *inode, loff_t bytes);
>> void inode_sub_bytes(struct inode *inode, loff_t bytes);
>> @@ -2482,6 +2484,8 @@ extern int vfs_stat(const char __user *, struct kstat *);
>> extern int vfs_lstat(const char __user *, struct kstat *);
>> extern int vfs_fstat(unsigned int, struct kstat *);
>> extern int vfs_fstatat(int , const char __user *, struct kstat *, int);
>> +extern int vfs_xstat(int, const char __user *, int, struct kstat *);
>> +extern int vfs_xfstat(unsigned int, struct kstat *);
>>
>> extern int do_vfs_ioctl(struct file *filp, unsigned int fd, unsigned int cmd,
>> unsigned long arg);
>> diff --git a/include/linux/stat.h b/include/linux/stat.h
>> index 611c398..0ff561a 100644
>> --- a/include/linux/stat.h
>> +++ b/include/linux/stat.h
>> @@ -3,6 +3,7 @@
>>
>> #ifdef __KERNEL__
>>
>> +#include <linux/types.h>
>> #include <asm/stat.h>
>>
>> #endif
>> @@ -46,6 +47,117 @@
>>
>> #endif
>>
>> +/*
>> + * Query request/result mask
>> + *
>> + * Bits should be set in request_mask to request particular items when calling
>> + * xstat() or fxstat().
>> + *
>> + * The bits in st_mask may or may not be set upon return, in part depending on
>> + * what was set in the mask argument:
>> + *
>> + * - if not available at all, the bit will be cleared before returning and the
>> + * field will be cleared; otherwise,
>> + *
>> + * - if AT_FORCE_ATTR_SYNC is set, then the datum will be synchronised to the
>> + * server and the field and bit will be set on return; otherwise,
>> + *
>> + * - if explicitly requested, the datum will be synchronised to a server or
>> + * other medium if out of date before being returned, and the bit will be set
>> + * on return; otherwise,
>> + *
>> + * - if not requested, but available in approximate form without any effort, it
>> + * will be filled in anyway, and the bit will be set upon return (it might
>> + * not be up to date, however, and no attempt will be made to synchronise the
>> + * internal state first); otherwise,
>> + *
>> + * - the field and the bit will be cleared before returning.
>> + *
>> + * Items in XSTAT_BASIC_STATS may be marked unavailable on return, but they
>> + * will have a value installed for compatibility purposes so that stat() and
>> + * co. can be emulated in userspace.
>> + */
>> +#define XSTAT_MODE 0x00000001U /* want/got st_mode */
>> +#define XSTAT_NLINK 0x00000002U /* want/got st_nlink */
>> +#define XSTAT_UID 0x00000004U /* want/got st_uid */
>> +#define XSTAT_GID 0x00000008U /* want/got st_gid */
>> +#define XSTAT_RDEV 0x00000010U /* want/got st_rdev */
>> +#define XSTAT_ATIME 0x00000020U /* want/got st_atime */
>> +#define XSTAT_MTIME 0x00000040U /* want/got st_mtime */
>> +#define XSTAT_CTIME 0x00000080U /* want/got st_ctime */
>> +#define XSTAT_INO 0x00000100U /* want/got st_ino */
>> +#define XSTAT_SIZE 0x00000200U /* want/got st_size */
>> +#define XSTAT_BLOCKS 0x00000400U /* want/got st_blocks */
>> +#define XSTAT_BASIC_STATS 0x000007ffU /* the stuff in the normal stat struct */
>> +#define XSTAT_IOC_FLAGS 0x00000800U /* want/got FS_IOC_GETFLAGS */
>> +#define XSTAT_BTIME 0x00001000U /* want/got st_btime */
>> +#define XSTAT_GEN 0x00002000U /* want/got st_gen */
>> +#define XSTAT_VERSION 0x00004000U /* want/got st_version */
>> +#define XSTAT_VOLUME_ID 0x00008000U /* want/got st_volume_id */
>> +#define XSTAT_ALL_STATS 0x0000ffffU /* all supported stats */
>> +
>> +/*
>> + * Extended stat structures
>> + */
>> +struct xstat_dev {
>> + uint32_t major, minor;
>> +};
>> +
>> +struct xstat_time {
>> + int64_t tv_sec;
>> + uint32_t tv_nsec;
>> + uint32_t tv_granularity; /* time granularity (in nS) */
>> +};
>> +
>> +struct xstat {
>> + uint32_t st_mask; /* what results were written */
>> + uint32_t st_mode; /* file mode */
>> + uint32_t st_nlink; /* number of hard links */
>> + uint32_t st_uid; /* user ID of owner */
>> + uint32_t st_gid; /* group ID of owner */
>> + uint32_t st_information; /* information about the file */
>> + uint32_t st_ioc_flags; /* as FS_IOC_GETFLAGS */
>> + uint32_t st_blksize; /* optimal size for filesystem I/O */
>> + struct xstat_dev st_rdev; /* device ID of special file */
>> + struct xstat_dev st_dev; /* ID of device containing file */
>> + struct xstat_time st_atime; /* last access time */
>> + struct xstat_time st_btime; /* file creation time */
>> + struct xstat_time st_ctime; /* last attribute change time */
>> + struct xstat_time st_mtime; /* last data modification time */
>> + uint64_t st_ino; /* inode number */
>> + uint64_t st_size; /* file size */
>> + uint64_t st_blocks; /* number of 512-byte blocks allocated */
>> + uint64_t st_gen; /* inode generation number */
>> + uint64_t st_version; /* data version number */
>> + uint8_t st_volume_id[16]; /* volume identifier */
>> + uint64_t __spares[11]; /* spare space for future expansion */
>> +};
>> +
>> +/*
>> + * Flags to be found in st_information
>> + *
>> + * These give information about the features or the state of a file that might
>> + * be of use to ordinary userspace programs such as GUIs or ls rather than
>> + * specialised tools.
>> + *
>> + * Additional information may be found in st_ioc_flags and we try not to
>> + * overlap with it.
>> + */
>> +#define XSTAT_INFO_ENCRYPTED 0x00000001U /* File is encrypted */
>> +#define XSTAT_INFO_TEMPORARY 0x00000002U /* File is temporary (NTFS/CIFS) */
>> +#define XSTAT_INFO_FABRICATED 0x00000004U /* File was made up by filesystem */
>> +#define XSTAT_INFO_KERNEL_API 0x00000008U /* File is kernel API (eg: procfs/sysfs) */
>> +#define XSTAT_INFO_REMOTE 0x00000010U /* File is remote */
>> +#define XSTAT_INFO_OFFLINE 0x00000020U /* File is offline (CIFS) */
>> +#define XSTAT_INFO_AUTOMOUNT 0x00000040U /* Dir is automount trigger */
>> +#define XSTAT_INFO_AUTODIR 0x00000080U /* Dir provides unlisted automounts */
>> +#define XSTAT_INFO_NONSYSTEM_OWNERSHIP 0x00000100U /* File has non-system ownership details */
>> +#define XSTAT_INFO_HAS_ACL 0x00000200U /* File has an ACL of some sort */
>> +#define XSTAT_INFO_REPARSE_POINT 0x00000400U /* File is reparse point (NTFS/CIFS) */
>> +#define XSTAT_INFO_HIDDEN 0x00000800U /* File is marked hidden (DOS+) */
>> +#define XSTAT_INFO_SYSTEM 0x00001000U /* File is marked system (DOS+) */
>> +#define XSTAT_INFO_ARCHIVE 0x00002000U /* File is marked archive (DOS+) */
>> +
>> #ifdef __KERNEL__
>> #define S_IRWXUGO (S_IRWXU|S_IRWXG|S_IRWXO)
>> #define S_IALLUGO (S_ISUID|S_ISGID|S_ISVTX|S_IRWXUGO)
>> @@ -60,6 +172,12 @@
>> #include <linux/time.h>
>>
>> struct kstat {
>> + u32 query_flags; /* operational flags */
>> +#define KSTAT_QUERY_FLAGS (AT_FORCE_ATTR_SYNC)
>> + u32 request_mask; /* what fields the user asked for */
>> + u32 result_mask; /* what fields the user got */
>> + u32 information;
>> + u32 ioc_flags; /* inode flags (FS_IOC_GETFLAGS) */
>> u64 ino;
>> dev_t dev;
>> umode_t mode;
>> @@ -67,14 +185,18 @@ struct kstat {
>> uid_t uid;
>> gid_t gid;
>> dev_t rdev;
>> + unsigned int tv_granularity; /* granularity of times (in nS) */
>> loff_t size;
>> - struct timespec atime;
>> + struct timespec atime;
>> struct timespec mtime;
>> struct timespec ctime;
>> + struct timespec btime; /* file creation time */
>> unsigned long blksize;
>> unsigned long long blocks;
>> + u64 gen; /* inode generation */
>> + u64 version; /* data version */
>> + unsigned char volume_id[16]; /* volume identifier */
>> };
>>
>> #endif
>> -
>> #endif
>> diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
>> index 3de3acb..ff9f8d9 100644
>> --- a/include/linux/syscalls.h
>> +++ b/include/linux/syscalls.h
>> @@ -45,6 +45,8 @@ struct shmid_ds;
>> struct sockaddr;
>> struct stat;
>> struct stat64;
>> +struct xstat_parameters;
>> +struct xstat;
>> struct statfs;
>> struct statfs64;
>> struct __sysctl_args;
>> @@ -858,4 +860,9 @@ asmlinkage long sys_process_vm_writev(pid_t pid,
>> unsigned long riovcnt,
>> unsigned long flags);
>>
>> +asmlinkage long sys_xstat(int dfd, const char __user *path, unsigned flags,
>> + unsigned mask, struct xstat __user *buffer);
>> +asmlinkage long sys_fxstat(unsigned fd, unsigned flags,
>> + unsigned mask, struct xstat __user *buffer);
>> +
>> #endif
>>
>> --
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>> More majordomo info at http://vger.kernel.org/majordomo-info.html
> --
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Cheers, Andreas
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