Hi David,
[Please CC linux-api@ on patches that change the API/ABI]
On Thu, Jul 1, 2010 at 1:36 AM, David Howells <dhowells@xxxxxxxxxx> wrote:
> Add a pair of system calls to make extended file stats available, including
> file creation time, inode version and data version where available through the
> underlying filesystem.
Just some random thoughts here. I've not tried to guess the overhead
of these ideas...
* Include information from the "inode_info" structure, most notably
i_flags, but perhaps other info as well.
* Return a bit mask indicating the presence of additional information
associated with the i-node. Here, I am thinking of flags that indicate
that the file has any of the following: capabilities, an ACL, and
extended attributes (obviously a superset of the previous). I could
imagine some apps that, having got the xstat info, would be interested
to obtain some of this other info.
Obviously, the above only make sense if the overhead of providing the
extra information is low.
> [This depends on the previously posted pair of patches to (a) constify a number
> of syscall string and buffer arguments and (b) rearrange AFS's use of
> i_version and i_generation].
>
> The following structures are defined for their use:
>
> struct xstat_parameters {
> unsigned long long request_mask;
> };
>
> struct xstat_dev {
> unsigned int major, minor;
> };
>
> struct xstat_time {
> unsigned long long tv_sec, tv_nsec;
> };
>
> struct xstat {
> unsigned int st_mode;
> unsigned int st_nlink;
> unsigned int st_uid;
> unsigned int st_gid;
> struct xstat_dev st_rdev;
> struct xstat_dev st_dev;
> struct xstat_time st_atime;
> struct xstat_time st_mtime;
> struct xstat_time st_ctime;
> struct xstat_time st_btime;
> unsigned long long st_ino;
> unsigned long long st_size;
> unsigned long long st_blksize;
> unsigned long long st_blocks;
> unsigned long long st_gen;
> unsigned long long st_data_version;
> unsigned long long st_result_mask;
> unsigned long long st_extra_results[0];
> };
>
> where 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),
> request_mask and st_result_mask are bitmasks of data desired/provided and
> st_extra_results[] is where as-yet undefined fields are appended.
>
> The defined bits in request_mask and st_result_mask are:
>
> XSTAT_REQUEST_MODE Want/got st_mode
> XSTAT_REQUEST_NLINK Want/got st_nlink
> XSTAT_REQUEST_UID Want/got st_uid
> XSTAT_REQUEST_GID Want/got st_gid
> XSTAT_REQUEST_RDEV Want/got st_rdev
> XSTAT_REQUEST_ATIME Want/got st_atime
> XSTAT_REQUEST_MTIME Want/got st_mtime
> XSTAT_REQUEST_CTIME Want/got st_ctime
> XSTAT_REQUEST_INO Want/got st_ino
> XSTAT_REQUEST_SIZE Want/got st_size
> XSTAT_REQUEST_BLOCKS Want/got st_blocks
> XSTAT_REQUEST__BASIC_STATS The stuff in the normal stat struct
> XSTAT_REQUEST_BTIME Want/got st_btime
> XSTAT_REQUEST_GEN Want/got st_gen
> XSTAT_REQUEST_DATA_VERSION Want/got st_data_version
> XSTAT_REQUEST__EXTENDED_STATS The stuff in the xstat struct
> XSTAT_REQUEST__ALL_STATS The defined set of requestables
>
> The system calls are:
>
> ssize_t ret = xstat(int dfd,
> const char *filename,
> unsigned flags,
> const struct xstat_parameters *params,
> struct xstat *buffer,
> size_t buflen);
>
> ssize_t ret = fxstat(unsigned fd,
> unsigned flags,
> const struct xstat_parameters *params,
> struct xstat *buffer,
> size_t buflen);
>
>
> 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.
>
> When the system call is executed, the request_mask bitmask is read from the
> parameter block to work out what the user is requesting. If params is NULL,
> then request_mask will be assumed to be XSTAT_REQUEST__GET_ANYWAY.
>
> The request_mask should be set by the caller to specify extra results that the
> caller may desire. These come in a number of classes:
>
> (0) dev, blksize.
>
> These are local data and are always available.
>
> (1) mode, nlinks, uid, gid, [amc]time, ino, size, 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.
>
> (2) 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, inode generation and data version.
>
> 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.
>
> (4) Extra results.
>
> These will only be returned if the caller asked for them by setting their
> bits in request_mask. They will be placed in the buffer after the xstat
> struct in ascending result_mask bit order. Any bit set in request_mask
> mask will be left set in result_mask if the result is available and
> cleared otherwise.
>
> The pointer into the results list will be rounded up to the nearest 8-byte
> boundary after each result is written in. The size of each extra result
> is specific to the definition for that result.
>
> No extra results are currently defined.
>
> If the buffer is insufficiently big, the syscall returns the amount of space it
> will need to write the complete result set and returns a partial result in the
> buffer.
>
> At the moment, this will only work on x86_64 as it requires system calls to be
> wired up.
>
>
> ===========
> FILESYSTEMS
> ===========
>
> The following filesystems have been modified to make use of this facility:
>
> (*) Ext4. This will return the creation time and inode version number for all
> files. It will, however, only return the data version number for
> directories unless the I_VERSION option is set on the filesystem.
>
> (*) AFS. This will return the vnode ID uniquifier as the inode version and
> the AFS data version number as the data version. There is no file
> creation time available.
>
> AFS should go to the server if AT_FORCE_ATTR_SYNC is specified.
>
> (*) NFS. This will return the change attribute if NFSv4 only. No other extra
> values are returned at this time.
>
> If AT_FORCE_ATTR_SYNC is set or mtime, ctime or data_version (NFSv4 only)
> are asked for then the outstanding writes will be written to the server
> first.
>
> If AT_FORCE_ATTR_SYNC is set or atime is requested then the attributes
> will be reread unconditionally, otherwise if any of data version (NFSv4
> only) XSTAT_REQUEST__BASIC_STATS are requested, then the attributes will
> be reread if the cached attributes have expired.
>
>
> =======
> TESTING
> =======
>
> The following test program can be used to test the xstat system call:
>
> #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_FORCE_ATTR_SYNC 0x800
>
> struct xstat_parameters {
> unsigned long long request_mask;
> #define XSTAT_REQUEST_MODE 0x00000001ULL
> #define XSTAT_REQUEST_NLINK 0x00000002ULL
> #define XSTAT_REQUEST_UID 0x00000004ULL
> #define XSTAT_REQUEST_GID 0x00000008ULL
> #define XSTAT_REQUEST_RDEV 0x00000010ULL
> #define XSTAT_REQUEST_ATIME 0x00000020ULL
> #define XSTAT_REQUEST_MTIME 0x00000040ULL
> #define XSTAT_REQUEST_CTIME 0x00000080ULL
> #define XSTAT_REQUEST_INO 0x00000100ULL
> #define XSTAT_REQUEST_SIZE 0x00000200ULL
> #define XSTAT_REQUEST_BLOCKS 0x00000400ULL
> #define XSTAT_REQUEST__BASIC_STATS 0x000007ffULL
> #define XSTAT_REQUEST_BTIME 0x00000800ULL
> #define XSTAT_REQUEST_GEN 0x00001000ULL
> #define XSTAT_REQUEST_DATA_VERSION 0x00002000ULL
> #define XSTAT_REQUEST__EXTENDED_STATS 0x00003fffULL
> #define XSTAT_REQUEST__ALL_STATS 0x00003fffULL
> };
>
> struct xstat_dev {
> unsigned int major;
> unsigned int minor;
> };
>
> struct xstat_time {
> unsigned long long tv_sec;
> unsigned long long tv_nsec;
> };
>
> struct xstat {
> unsigned int st_mode;
> unsigned int st_nlink;
> unsigned int st_uid;
> unsigned int st_gid;
> struct xstat_dev st_rdev;
> struct xstat_dev st_dev;
> struct xstat_time st_atim;
> struct xstat_time st_mtim;
> struct xstat_time st_ctim;
> struct xstat_time st_btim;
> unsigned long long st_ino;
> unsigned long long st_size;
> unsigned long long st_blksize;
> unsigned long long st_blocks;
> unsigned long long st_gen;
> unsigned long long st_data_version;
> unsigned long long st_result_mask;
> unsigned long long st_extra_results[0];
> };
>
> #define __NR_xstat 300
> #define __NR_fxstat 301
>
> static __attribute__((unused))
> ssize_t xstat(int dfd, const char *filename, unsigned flags,
> struct xstat_parameters *params,
> struct xstat *buffer, size_t bufsize)
> {
> return syscall(__NR_xstat, dfd, filename, flags,
> params, buffer, bufsize);
> }
>
> static __attribute__((unused))
> ssize_t fxstat(int fd, unsigned flags,
> struct xstat_parameters *params,
> struct xstat *buffer, size_t bufsize)
> {
> return syscall(__NR_fxstat, fd, flags,
> params, buffer, bufsize);
> }
>
> 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(".%09llu", 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=%llx\n", xst->st_result_mask);
>
> printf(" ");
> if (xst->st_result_mask & XSTAT_REQUEST_SIZE)
> printf(" Size: %-15llu", xst->st_size);
> if (xst->st_result_mask & XSTAT_REQUEST_BLOCKS)
> printf(" Blocks: %-10llu", xst->st_blocks);
> printf(" IO Block: %-6llu ", xst->st_blksize);
> if (xst->st_result_mask & XSTAT_REQUEST_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_result_mask & XSTAT_REQUEST_INO)
> printf(" Inode: %-11llu", xst->st_ino);
> if (xst->st_result_mask & XSTAT_REQUEST_SIZE)
> printf(" Links: %-5u", xst->st_nlink);
> if (xst->st_result_mask & XSTAT_REQUEST_RDEV)
> printf(" Device type: %u,%u",
> xst->st_rdev.major, xst->st_rdev.minor);
> printf("\n");
>
> if (xst->st_result_mask & XSTAT_REQUEST_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_result_mask & XSTAT_REQUEST_UID)
> printf("Uid: %d \n", xst->st_uid);
> if (xst->st_result_mask & XSTAT_REQUEST_GID)
> printf("Gid: %u\n", xst->st_gid);
>
> if (xst->st_result_mask & XSTAT_REQUEST_ATIME)
> print_time("Access: ", &xst->st_atim);
> if (xst->st_result_mask & XSTAT_REQUEST_MTIME)
> print_time("Modify: ", &xst->st_mtim);
> if (xst->st_result_mask & XSTAT_REQUEST_CTIME)
> print_time("Change: ", &xst->st_ctim);
> if (xst->st_result_mask & XSTAT_REQUEST_BTIME)
> print_time("Create: ", &xst->st_btim);
>
> if (xst->st_result_mask & XSTAT_REQUEST_GEN)
> printf("Inode version: %llxh\n", xst->st_gen);
> if (xst->st_result_mask & XSTAT_REQUEST_DATA_VERSION)
> printf("Data version: %llxh\n", xst->st_data_version);
> }
>
> int main(int argc, char **argv)
> {
> struct xstat_parameters params;
> struct xstat xst;
> int ret, atflag = AT_SYMLINK_NOFOLLOW;
>
> unsigned long long query =
> XSTAT_REQUEST__BASIC_STATS |
> XSTAT_REQUEST_BTIME |
> XSTAT_REQUEST_GEN |
> XSTAT_REQUEST_DATA_VERSION;
>
> 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) {
> query &= ~XSTAT_REQUEST__BASIC_STATS;
> continue;
> }
>
> memset(&xst, 0xbf, sizeof(xst));
> params.request_mask = query;
> ret = xstat(AT_FDCWD, *argv, atflag, ¶ms, &xst, sizeof(xst));
> printf("xstat(%s) = %d\n", *argv, ret);
> if (ret < 0) {
> perror(*argv);
> exit(1);
> }
>
> dump_xstat(&xst);
> }
> return 0;
> }
>
> Just compile and run, passing it paths to the files you want to examine:
>
> [root@andromeda ~]# /tmp/xstat -O /dev/tty
> xstat(/dev/tty) = 152
> results=7ff
> Size: 0 Blocks: 0 IO Block: 4096 character special file
> Device: 00:0f Inode: 246 Links: 1 Device type: 5,0
> Access: (0666/crw-rw-rw-) Uid: 0
> Gid: 5
> Access: 2010-06-30 16:25:01.813517001+0100
> Modify: 2010-06-30 16:25:01.813517001+0100
> Change: 2010-06-30 16:25:01.813517001+0100
>
> [root@andromeda ~]# /tmp/xstat /var/cache/fscache/cache/
> xstat(/var/cache/fscache/cache/) = 152
> results=3fef
> Size: 4096 Blocks: 16 IO Block: 4096 directory
> Device: 08:06 Inode: 130561 Links: 3
> Access: (0700/drwx------) Uid: 0
> Gid: 0
> Access: 2010-06-29 18:16:33.680703545+0100
> Modify: 2010-06-29 18:16:20.132786632+0100
> Change: 2010-06-29 18:16:20.132786632+0100
> Create: 2010-06-25 15:17:39.471199293+0100
> Inode version: f585ab70h
> Data version: 2h
>
> Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
> ---
>
> arch/x86/include/asm/unistd_32.h | 4 +
> arch/x86/include/asm/unistd_64.h | 4 +
> fs/afs/inode.c | 11 +-
> fs/ecryptfs/inode.c | 2
> fs/ext4/ext4.h | 2
> fs/ext4/file.c | 2
> fs/ext4/inode.c | 27 +++++-
> fs/ext4/namei.c | 2
> fs/ext4/symlink.c | 2
> fs/nfs/inode.c | 46 +++++++---
> fs/nfsd/nfs3proc.c | 2
> fs/nfsd/nfs3xdr.c | 4 +
> fs/nfsd/nfs4xdr.c | 4 +
> fs/nfsd/nfsproc.c | 6 +
> fs/nfsd/nfsxdr.c | 2
> fs/stat.c | 175 ++++++++++++++++++++++++++++++++++----
> include/linux/fcntl.h | 1
> include/linux/fs.h | 2
> include/linux/stat.h | 103 ++++++++++++++++++++++
> include/linux/syscalls.h | 9 ++
> 20 files changed, 368 insertions(+), 42 deletions(-)
>
> diff --git a/arch/x86/include/asm/unistd_32.h b/arch/x86/include/asm/unistd_32.h
> index beb9b5f..a9953cc 100644
> --- a/arch/x86/include/asm/unistd_32.h
> +++ b/arch/x86/include/asm/unistd_32.h
> @@ -343,10 +343,12 @@
> #define __NR_rt_tgsigqueueinfo 335
> #define __NR_perf_event_open 336
> #define __NR_recvmmsg 337
> +#define __NR_xstat 338
> +#define __NR_fxstat 339
>
> #ifdef __KERNEL__
>
> -#define NR_syscalls 338
> +#define NR_syscalls 340
>
> #define __ARCH_WANT_IPC_PARSE_VERSION
> #define __ARCH_WANT_OLD_READDIR
> diff --git a/arch/x86/include/asm/unistd_64.h b/arch/x86/include/asm/unistd_64.h
> index ff4307b..c90d240 100644
> --- a/arch/x86/include/asm/unistd_64.h
> +++ b/arch/x86/include/asm/unistd_64.h
> @@ -663,6 +663,10 @@ __SYSCALL(__NR_rt_tgsigqueueinfo, sys_rt_tgsigqueueinfo)
> __SYSCALL(__NR_perf_event_open, sys_perf_event_open)
> #define __NR_recvmmsg 299
> __SYSCALL(__NR_recvmmsg, sys_recvmmsg)
> +#define __NR_xstat 300
> +__SYSCALL(__NR_xstat, sys_xstat)
> +#define __NR_fxstat 301
> +__SYSCALL(__NR_fxstat, sys_fxstat)
>
> #ifndef __NO_STUBS
> #define __ARCH_WANT_OLD_READDIR
> diff --git a/fs/afs/inode.c b/fs/afs/inode.c
> index ee3190a..f624c5a 100644
> --- a/fs/afs/inode.c
> +++ b/fs/afs/inode.c
> @@ -300,16 +300,17 @@ error_unlock:
> /*
> * read the attributes of an inode
> */
> -int afs_getattr(struct vfsmount *mnt, struct dentry *dentry,
> - struct kstat *stat)
> +int afs_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
> {
> - struct inode *inode;
> -
> - inode = dentry->d_inode;
> + struct inode *inode = dentry->d_inode;
>
> _enter("{ ino=%lu v=%u }", inode->i_ino, inode->i_generation);
>
> generic_fillattr(inode, stat);
> +
> + stat->result_mask |= XSTAT_REQUEST_GEN | XSTAT_REQUEST_DATA_VERSION;
> + stat->gen = inode->i_generation;
> + stat->data_version = inode->i_version;
> return 0;
> }
>
> diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c
> index 31ef525..0b02272 100644
> --- a/fs/ecryptfs/inode.c
> +++ b/fs/ecryptfs/inode.c
> @@ -994,6 +994,8 @@ int ecryptfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
> struct kstat lower_stat;
> int rc;
>
> + lower_stat.query_flags = stat->query_flags;
> + lower_stat.request_mask = stat->request_mask | XSTAT_REQUEST_BLOCKS;
> rc = vfs_getattr(ecryptfs_dentry_to_lower_mnt(dentry),
> ecryptfs_dentry_to_lower(dentry), &lower_stat);
> if (!rc) {
> diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
> index 19a4de5..96823f3 100644
> --- a/fs/ext4/ext4.h
> +++ b/fs/ext4/ext4.h
> @@ -1571,6 +1571,8 @@ extern int ext4_write_inode(struct inode *, struct writeback_control *);
> extern int ext4_setattr(struct dentry *, struct iattr *);
> extern int ext4_getattr(struct vfsmount *mnt, struct dentry *dentry,
> struct kstat *stat);
> +extern int ext4_file_getattr(struct vfsmount *mnt, struct dentry *dentry,
> + struct kstat *stat);
> extern void ext4_delete_inode(struct inode *);
> extern int ext4_sync_inode(handle_t *, struct inode *);
> extern void ext4_dirty_inode(struct inode *);
> diff --git a/fs/ext4/file.c b/fs/ext4/file.c
> index 5313ae4..18c29ab 100644
> --- a/fs/ext4/file.c
> +++ b/fs/ext4/file.c
> @@ -150,7 +150,7 @@ const struct file_operations ext4_file_operations = {
> const struct inode_operations ext4_file_inode_operations = {
> .truncate = ext4_truncate,
> .setattr = ext4_setattr,
> - .getattr = ext4_getattr,
> + .getattr = ext4_file_getattr,
> #ifdef CONFIG_EXT4_FS_XATTR
> .setxattr = generic_setxattr,
> .getxattr = generic_getxattr,
> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> index 42272d6..f9a730a 100644
> --- a/fs/ext4/inode.c
> +++ b/fs/ext4/inode.c
> @@ -5550,12 +5550,33 @@ err_out:
> int ext4_getattr(struct vfsmount *mnt, struct dentry *dentry,
> struct kstat *stat)
> {
> - struct inode *inode;
> - unsigned long delalloc_blocks;
> + struct inode *inode = dentry->d_inode;
>
> - inode = dentry->d_inode;
> generic_fillattr(inode, stat);
>
> + stat->result_mask |= XSTAT_REQUEST_BTIME;
> + stat->btime.tv_sec = EXT4_I(inode)->i_crtime.tv_sec;
> + stat->btime.tv_nsec = EXT4_I(inode)->i_crtime.tv_nsec;
> +
> + if (inode->i_ino != EXT4_ROOT_INO) {
> + stat->result_mask |= XSTAT_REQUEST_GEN;
> + stat->gen = inode->i_generation;
> + }
> + if (S_ISDIR(inode->i_mode) || test_opt(inode->i_sb, I_VERSION)) {
> + stat->result_mask |= XSTAT_REQUEST_DATA_VERSION;
> + stat->data_version = inode->i_version;
> + }
> + return 0;
> +}
> +
> +int ext4_file_getattr(struct vfsmount *mnt, struct dentry *dentry,
> + struct kstat *stat)
> +{
> + struct inode *inode = dentry->d_inode;
> + unsigned long delalloc_blocks;
> +
> + ext4_getattr(mnt, dentry, stat);
> +
> /*
> * We can't update i_blocks if the block allocation is delayed
> * otherwise in the case of system crash before the real block
> diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
> index a43e661..0f776c7 100644
> --- a/fs/ext4/namei.c
> +++ b/fs/ext4/namei.c
> @@ -2542,6 +2542,7 @@ const struct inode_operations ext4_dir_inode_operations = {
> .mknod = ext4_mknod,
> .rename = ext4_rename,
> .setattr = ext4_setattr,
> + .getattr = ext4_getattr,
> #ifdef CONFIG_EXT4_FS_XATTR
> .setxattr = generic_setxattr,
> .getxattr = generic_getxattr,
> @@ -2554,6 +2555,7 @@ const struct inode_operations ext4_dir_inode_operations = {
>
> const struct inode_operations ext4_special_inode_operations = {
> .setattr = ext4_setattr,
> + .getattr = ext4_getattr,
> #ifdef CONFIG_EXT4_FS_XATTR
> .setxattr = generic_setxattr,
> .getxattr = generic_getxattr,
> diff --git a/fs/ext4/symlink.c b/fs/ext4/symlink.c
> index ed9354a..d8fe7fb 100644
> --- a/fs/ext4/symlink.c
> +++ b/fs/ext4/symlink.c
> @@ -35,6 +35,7 @@ const struct inode_operations ext4_symlink_inode_operations = {
> .follow_link = page_follow_link_light,
> .put_link = page_put_link,
> .setattr = ext4_setattr,
> + .getattr = ext4_getattr,
> #ifdef CONFIG_EXT4_FS_XATTR
> .setxattr = generic_setxattr,
> .getxattr = generic_getxattr,
> @@ -47,6 +48,7 @@ const struct inode_operations ext4_fast_symlink_inode_operations = {
> .readlink = generic_readlink,
> .follow_link = ext4_follow_link,
> .setattr = ext4_setattr,
> + .getattr = ext4_getattr,
> #ifdef CONFIG_EXT4_FS_XATTR
> .setxattr = generic_setxattr,
> .getxattr = generic_getxattr,
> diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
> index 099b351..8c6de96 100644
> --- a/fs/nfs/inode.c
> +++ b/fs/nfs/inode.c
> @@ -495,11 +495,21 @@ void nfs_setattr_update_inode(struct inode *inode, struct iattr *attr)
> int nfs_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
> {
> struct inode *inode = dentry->d_inode;
> + unsigned force = stat->query_flags & AT_FORCE_ATTR_SYNC;
> int need_atime = NFS_I(inode)->cache_validity & NFS_INO_INVALID_ATIME;
> int err;
>
> - /* Flush out writes to the server in order to update c/mtime. */
> - if (S_ISREG(inode->i_mode)) {
> + if (NFS_SERVER(inode)->nfs_client->rpc_ops->version < 4)
> + stat->request_mask &= ~XSTAT_REQUEST_DATA_VERSION;
> +
> + /* Flush out writes to the server in order to update c/mtime
> + * or data version if the user wants them */
> + if ((force || stat->request_mask & (XSTAT_REQUEST_MTIME |
> + XSTAT_REQUEST_CTIME |
> + XSTAT_REQUEST_DATA_VERSION
> + )) &&
> + S_ISREG(inode->i_mode)
> + ) {
> err = filemap_write_and_wait(inode->i_mapping);
> if (err)
> goto out;
> @@ -514,18 +524,30 @@ int nfs_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
> * - NFS never sets MS_NOATIME or MS_NODIRATIME so there is
> * no point in checking those.
> */
> - if ((mnt->mnt_flags & MNT_NOATIME) ||
> - ((mnt->mnt_flags & MNT_NODIRATIME) && S_ISDIR(inode->i_mode)))
> + if (!(stat->request_mask & XSTAT_REQUEST_ATIME) ||
> + (mnt->mnt_flags & MNT_NOATIME) ||
> + ((mnt->mnt_flags & MNT_NODIRATIME) && S_ISDIR(inode->i_mode)))
> need_atime = 0;
>
> - if (need_atime)
> - err = __nfs_revalidate_inode(NFS_SERVER(inode), inode);
> - else
> - err = nfs_revalidate_inode(NFS_SERVER(inode), inode);
> - if (!err) {
> - generic_fillattr(inode, stat);
> - stat->ino = nfs_compat_user_ino64(NFS_FILEID(inode));
> + if (force || stat->request_mask & (XSTAT_REQUEST__BASIC_STATS |
> + XSTAT_REQUEST_DATA_VERSION)
> + ) {
> + if (force || need_atime)
> + err = __nfs_revalidate_inode(NFS_SERVER(inode), inode);
> + else
> + err = nfs_revalidate_inode(NFS_SERVER(inode), inode);
> + if (err)
> + goto out;
> }
> +
> + generic_fillattr(inode, stat);
> + stat->ino = nfs_compat_user_ino64(NFS_FILEID(inode));
> +
> + if (stat->request_mask & XSTAT_REQUEST_DATA_VERSION) {
> + stat->data_version = NFS_I(inode)->change_attr;
> + stat->result_mask |= XSTAT_REQUEST_DATA_VERSION;
> + }
> +
> out:
> return err;
> }
> @@ -770,7 +792,7 @@ int nfs_revalidate_inode(struct nfs_server *server, struct inode *inode)
> static int nfs_invalidate_mapping(struct inode *inode, struct address_space *mapping)
> {
> struct nfs_inode *nfsi = NFS_I(inode);
> -
> +
> if (mapping->nrpages != 0) {
> int ret = invalidate_inode_pages2(mapping);
> if (ret < 0)
> diff --git a/fs/nfsd/nfs3proc.c b/fs/nfsd/nfs3proc.c
> index 3d68f45..310ff05 100644
> --- a/fs/nfsd/nfs3proc.c
> +++ b/fs/nfsd/nfs3proc.c
> @@ -55,6 +55,8 @@ nfsd3_proc_getattr(struct svc_rqst *rqstp, struct nfsd_fhandle *argp,
> if (nfserr)
> RETURN_STATUS(nfserr);
>
> + resp->stat.query_flags = 0;
> + resp->stat.request_mask = XSTAT_REQUEST__EXTENDED_STATS;
> err = vfs_getattr(resp->fh.fh_export->ex_path.mnt,
> resp->fh.fh_dentry, &resp->stat);
> nfserr = nfserrno(err);
> diff --git a/fs/nfsd/nfs3xdr.c b/fs/nfsd/nfs3xdr.c
> index 2a533a0..eaa3c3b 100644
> --- a/fs/nfsd/nfs3xdr.c
> +++ b/fs/nfsd/nfs3xdr.c
> @@ -205,6 +205,8 @@ encode_post_op_attr(struct svc_rqst *rqstp, __be32 *p, struct svc_fh *fhp)
> int err;
> struct kstat stat;
>
> + stat.query_flags = 0;
> + stat.request_mask = XSTAT_REQUEST__EXTENDED_STATS;
> err = vfs_getattr(fhp->fh_export->ex_path.mnt, dentry, &stat);
> if (!err) {
> *p++ = xdr_one; /* attributes follow */
> @@ -257,6 +259,8 @@ void fill_post_wcc(struct svc_fh *fhp)
> if (fhp->fh_post_saved)
> printk("nfsd: inode locked twice during operation.\n");
>
> + fhp->fh_post_attr.query_flags = 0;
> + fhp->fh_post_attr.request_mask = XSTAT_REQUEST__EXTENDED_STATS;
> err = vfs_getattr(fhp->fh_export->ex_path.mnt, fhp->fh_dentry,
> &fhp->fh_post_attr);
> fhp->fh_post_change = fhp->fh_dentry->d_inode->i_version;
> diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
> index ac17a70..e9d1b59 100644
> --- a/fs/nfsd/nfs4xdr.c
> +++ b/fs/nfsd/nfs4xdr.c
> @@ -1769,6 +1769,8 @@ nfsd4_encode_fattr(struct svc_fh *fhp, struct svc_export *exp,
> goto out;
> }
>
> + stat.query_flags = 0;
> + stat.request_mask = XSTAT_REQUEST__EXTENDED_STATS;
> err = vfs_getattr(exp->ex_path.mnt, dentry, &stat);
> if (err)
> goto out_nfserr;
> @@ -2139,6 +2141,8 @@ out_acl:
> if (path.dentry != path.mnt->mnt_root)
> break;
> }
> + stat.query_flags = 0;
> + stat.request_mask = XSTAT_REQUEST__EXTENDED_STATS;
> err = vfs_getattr(path.mnt, path.dentry, &stat);
> path_put(&path);
> if (err)
> diff --git a/fs/nfsd/nfsproc.c b/fs/nfsd/nfsproc.c
> index a047ad6..7c0e74b 100644
> --- a/fs/nfsd/nfsproc.c
> +++ b/fs/nfsd/nfsproc.c
> @@ -26,6 +26,8 @@ static __be32
> nfsd_return_attrs(__be32 err, struct nfsd_attrstat *resp)
> {
> if (err) return err;
> + resp->stat.query_flags = 0;
> + resp->stat.request_mask = XSTAT_REQUEST__EXTENDED_STATS;
> return nfserrno(vfs_getattr(resp->fh.fh_export->ex_path.mnt,
> resp->fh.fh_dentry,
> &resp->stat));
> @@ -34,6 +36,8 @@ static __be32
> nfsd_return_dirop(__be32 err, struct nfsd_diropres *resp)
> {
> if (err) return err;
> + resp->stat.query_flags = 0;
> + resp->stat.request_mask = XSTAT_REQUEST__EXTENDED_STATS;
> return nfserrno(vfs_getattr(resp->fh.fh_export->ex_path.mnt,
> resp->fh.fh_dentry,
> &resp->stat));
> @@ -150,6 +154,8 @@ nfsd_proc_read(struct svc_rqst *rqstp, struct nfsd_readargs *argp,
> &resp->count);
>
> if (nfserr) return nfserr;
> + resp->stat.query_flags = 0;
> + resp->stat.request_mask = XSTAT_REQUEST__EXTENDED_STATS;
> return nfserrno(vfs_getattr(resp->fh.fh_export->ex_path.mnt,
> resp->fh.fh_dentry,
> &resp->stat));
> diff --git a/fs/nfsd/nfsxdr.c b/fs/nfsd/nfsxdr.c
> index 4ce005d..a595fb6 100644
> --- a/fs/nfsd/nfsxdr.c
> +++ b/fs/nfsd/nfsxdr.c
> @@ -197,6 +197,8 @@ encode_fattr(struct svc_rqst *rqstp, __be32 *p, struct svc_fh *fhp,
> __be32 *nfs2svc_encode_fattr(struct svc_rqst *rqstp, __be32 *p, struct svc_fh *fhp)
> {
> struct kstat stat;
> + stat.query_flags = 0;
> + stat.request_mask = XSTAT_REQUEST__EXTENDED_STATS;
> vfs_getattr(fhp->fh_export->ex_path.mnt, fhp->fh_dentry, &stat);
> return encode_fattr(rqstp, p, fhp, &stat);
> }
> diff --git a/fs/stat.c b/fs/stat.c
> index 12e90e2..2fb1527 100644
> --- a/fs/stat.c
> +++ b/fs/stat.c
> @@ -33,6 +33,9 @@ void generic_fillattr(struct inode *inode, struct kstat *stat)
> stat->size = i_size_read(inode);
> stat->blocks = inode->i_blocks;
> stat->blksize = (1 << inode->i_blkbits);
> + stat->result_mask |= XSTAT_REQUEST__BASIC_STATS & ~XSTAT_REQUEST_RDEV;
> + if (unlikely(S_ISBLK(stat->mode) || S_ISCHR(stat->mode)))
> + stat->result_mask |= XSTAT_REQUEST_RDEV;
> }
>
> EXPORT_SYMBOL(generic_fillattr);
> @@ -42,6 +45,8 @@ int vfs_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
> struct inode *inode = dentry->d_inode;
> int retval;
>
> + stat->result_mask = 0;
> +
> retval = security_inode_getattr(mnt, dentry);
> if (retval)
> return retval;
> @@ -55,41 +60,64 @@ int vfs_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
>
> EXPORT_SYMBOL(vfs_getattr);
>
> -int vfs_fstat(unsigned int fd, struct kstat *stat)
> +/*
> + * VFS entrypoint to get extended stats by file descriptor
> + */
> +int vfs_fxstat(unsigned int fd, int flags, struct kstat *stat)
> {
> struct file *f = fget(fd);
> int error = -EBADF;
>
> + if (flags & ~KSTAT_QUERY_FLAGS)
> + return -EINVAL;
> + stat->query_flags = flags;
> +
> if (f) {
> error = vfs_getattr(f->f_path.mnt, f->f_path.dentry, stat);
> fput(f);
> }
> return error;
> }
> +EXPORT_SYMBOL(vfs_fxstat);
> +
> +int vfs_fstat(unsigned int fd, struct kstat *stat)
> +{
> + stat->request_mask = XSTAT_REQUEST__BASIC_STATS;
> + return vfs_fxstat(fd, 0, stat);
> +}
> EXPORT_SYMBOL(vfs_fstat);
>
> -int vfs_fstatat(int dfd, const char __user *filename, struct kstat *stat,
> - int flag)
> +/*
> + * VFS entrypoint to get extended stats by filename
> + */
> +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;
>
> - if ((flag & ~AT_SYMLINK_NOFOLLOW) != 0)
> - goto out;
> + if (flags & ~(AT_SYMLINK_NOFOLLOW | KSTAT_QUERY_FLAGS))
> + return -EINVAL;
>
> - if (!(flag & AT_SYMLINK_NOFOLLOW))
> - lookup_flags |= LOOKUP_FOLLOW;
> + stat->query_flags = flags;
> + lookup_flags = (flags & AT_SYMLINK_NOFOLLOW) ? 0 : LOOKUP_FOLLOW;
>
> 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_getattr(path.mnt, path.dentry, stat);
> + path_put(&path);
> + }
> return error;
> }
> +EXPORT_SYMBOL(vfs_xstat);
> +
> +int vfs_fstatat(int dfd, const char __user *filename, struct kstat *stat,
> + int flags)
> +{
> + stat->request_mask = XSTAT_REQUEST__BASIC_STATS;
> + stat->query_flags = 0;
> + return vfs_xstat(dfd, filename, flags, stat);
> +}
> EXPORT_SYMBOL(vfs_fstatat);
>
> int vfs_stat(const char __user *name, struct kstat *stat)
> @@ -115,7 +143,7 @@ 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",
> @@ -140,7 +168,7 @@ 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;
> @@ -222,7 +250,7 @@ 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;
> @@ -408,6 +436,117 @@ SYSCALL_DEFINE4(fstatat64, int, dfd, const char __user *, filename,
> }
> #endif /* __ARCH_WANT_STAT64 */
>
> +/*
> + * Get the xstat parameters if supplied
> + */
> +static int xstat_get_params(struct xstat_parameters __user *_params,
> + struct kstat *stat)
> +{
> + struct xstat_parameters params;
> +
> + memset(stat, 0xde, sizeof(*stat)); // DEBUGGING
> +
> + if (_params) {
> + if (copy_from_user(¶ms, _params, sizeof(params)) != 0)
> + return -EFAULT;
> + stat->request_mask =
> + params.request_mask & XSTAT_REQUEST__ALL_STATS;
> + } else {
> + stat->request_mask = XSTAT_REQUEST__EXTENDED_STATS;
> + }
> + stat->result_mask = 0;
> + return 0;
> +}
> +
> +/*
> + * copy the extended stats to userspace and return the amount of data written
> + * into the buffer
> + */
> +static long xstat_set_result(struct kstat *stat,
> + struct xstat __user *buffer, size_t bufsize)
> +{
> + struct xstat tmp;
> + size_t copy;
> +
> + /* transfer the fixed results */
> + memset(&tmp, 0, sizeof(tmp));
> + tmp.st_result_mask = stat->result_mask;
> + tmp.st_mode = stat->mode;
> + tmp.st_nlink = stat->nlink;
> + tmp.st_uid = stat->uid;
> + tmp.st_gid = stat->gid;
> + tmp.st_blksize = stat->blksize;
> + tmp.st_rdev.major = MAJOR(stat->rdev);
> + tmp.st_rdev.minor = MINOR(stat->rdev);
> + tmp.st_dev.major = MAJOR(stat->dev);
> + tmp.st_dev.minor = MINOR(stat->dev);
> + tmp.st_atime.tv_sec = stat->atime.tv_sec;
> + tmp.st_atime.tv_nsec = stat->atime.tv_nsec;
> + tmp.st_mtime.tv_sec = stat->mtime.tv_sec;
> + tmp.st_mtime.tv_nsec = stat->mtime.tv_nsec;
> + tmp.st_ctime.tv_sec = stat->ctime.tv_sec;
> + tmp.st_ctime.tv_nsec = stat->ctime.tv_nsec;
> + tmp.st_ino = stat->ino;
> + tmp.st_size = stat->size;
> + tmp.st_blocks = stat->blocks;
> +
> + if (tmp.st_result_mask & XSTAT_REQUEST_BTIME) {
> + tmp.st_btime.tv_sec = stat->btime.tv_sec;
> + tmp.st_btime.tv_nsec = stat->btime.tv_nsec;
> + }
> + if (tmp.st_result_mask & XSTAT_REQUEST_GEN)
> + tmp.st_gen = stat->gen;
> + if (tmp.st_result_mask & XSTAT_REQUEST_DATA_VERSION)
> + tmp.st_data_version = stat->data_version;
> +
> + copy = sizeof(tmp);
> + if (copy > bufsize)
> + copy = bufsize;
> + if (copy_to_user(buffer, &tmp, copy) != 0)
> + return -EFAULT;
> + return sizeof(tmp);
> +}
> +
> +/*
> + * System call to get extended stats by path
> + */
> +SYSCALL_DEFINE6(xstat,
> + int, dfd, const char __user *, filename, unsigned, atflag,
> + struct xstat_parameters __user *, params,
> + struct xstat __user *, buffer, size_t, bufsize)
> +{
> + struct kstat stat;
> + int error;
> +
> + error = xstat_get_params(params, &stat);
> + if (error != 0)
> + return error;
> + error = vfs_xstat(dfd, filename, atflag, &stat);
> + if (error)
> + return error;
> + return xstat_set_result(&stat, buffer, bufsize);
> +}
> +
> +/*
> + * System call to get extended stats by file descriptor
> + */
> +SYSCALL_DEFINE5(fxstat, unsigned int, fd, unsigned int, flags,
> + struct xstat_parameters __user *, params,
> + struct xstat __user *, buffer, size_t, bufsize)
> +{
> + struct kstat stat;
> + int error;
> +
> + error = xstat_get_params(params, &stat);
> + if (error < 0)
> + return error;
> + error = vfs_fxstat(fd, flags, &stat);
> + if (error)
> + return error;
> +
> + return xstat_set_result(&stat, buffer, bufsize);
> +}
> +
> /* 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 afc00af..bcf8083 100644
> --- a/include/linux/fcntl.h
> +++ b/include/linux/fcntl.h
> @@ -45,6 +45,7 @@
> #define AT_REMOVEDIR 0x200 /* Remove directory instead of
> unlinking file. */
> #define AT_SYMLINK_FOLLOW 0x400 /* Follow symbolic links. */
> +#define AT_FORCE_ATTR_SYNC 0x800 /* 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 a18bcea..9ce2119 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -2343,6 +2343,8 @@ 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..e0b89e4 100644
> --- a/include/linux/stat.h
> +++ b/include/linux/stat.h
> @@ -46,6 +46,99 @@
>
> #endif
>
> +/*
> + * Extended stat structures
> + */
> +struct xstat_parameters {
> + /* Query request/result mask
> + *
> + * Bits should be set in request_mask to request particular items
> + * before calling xstat() or fxstat().
> + *
> + * For each item in the set XSTAT_REQUEST__EXTENDED_STATS:
> + *
> + * - 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 bit will be set on return; otherwise,
> + *
> + * - if requested, the datum will be synchronised to a server or other
> + * hardware 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 bit will be cleared before returning, and the field will be
> + * cleared.
> + *
> + * For each item not in the set XSTAT_REQUEST__EXTENDED_STATS
> + *
> + * - if not available at all, the bit will be cleared, and no result
> + * data will be returned; otherwise,
> + *
> + * - if requested, the datum will be synchronised to a server or other
> + * hardware before being appended if necessary, and the bit will be
> + * set on return; otherwise,
> + *
> + * - the bit will be cleared, and no result data will be returned.
> + *
> + * Items in XSTAT_REQUEST__BASIC_STATS may be marked unavailable on
> + * return, but they will have a value installed for compatibility
> + * purposes.
> + */
> + unsigned long long request_mask;
> +#define XSTAT_REQUEST_MODE 0x00000001ULL /* want/got st_mode */
> +#define XSTAT_REQUEST_NLINK 0x00000002ULL /* want/got st_nlink */
> +#define XSTAT_REQUEST_UID 0x00000004ULL /* want/got st_uid */
> +#define XSTAT_REQUEST_GID 0x00000008ULL /* want/got st_gid */
> +#define XSTAT_REQUEST_RDEV 0x00000010ULL /* want/got st_rdev */
> +#define XSTAT_REQUEST_ATIME 0x00000020ULL /* want/got st_atime */
> +#define XSTAT_REQUEST_MTIME 0x00000040ULL /* want/got st_mtime */
> +#define XSTAT_REQUEST_CTIME 0x00000080ULL /* want/got st_ctime */
> +#define XSTAT_REQUEST_INO 0x00000100ULL /* want/got st_ino */
> +#define XSTAT_REQUEST_SIZE 0x00000200ULL /* want/got st_size */
> +#define XSTAT_REQUEST_BLOCKS 0x00000400ULL /* want/got st_blocks */
> +#define XSTAT_REQUEST__BASIC_STATS 0x000007ffULL /* the stuff in the normal stat struct */
> +#define XSTAT_REQUEST_BTIME 0x00000800ULL /* want/got st_btime */
> +#define XSTAT_REQUEST_GEN 0x00001000ULL /* want/got st_gen */
> +#define XSTAT_REQUEST_DATA_VERSION 0x00002000ULL /* want/got st_data_version */
> +#define XSTAT_REQUEST__EXTENDED_STATS 0x00003fffULL /* the stuff in the xstat struct */
> +#define XSTAT_REQUEST__ALL_STATS 0x00003fffULL /* the defined set of requestables */
> +};
> +
> +struct xstat_dev {
> + unsigned int major, minor;
> +};
> +
> +struct xstat_time {
> + unsigned long long tv_sec, tv_nsec;
> +};
> +
> +struct xstat {
> + unsigned int st_mode; /* file mode */
> + unsigned int st_nlink; /* number of hard links */
> + unsigned int st_uid; /* user ID of owner */
> + unsigned int st_gid; /* group ID of owner */
> + 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_mtime; /* last data modification time */
> + struct xstat_time st_ctime; /* last attribute change time */
> + struct xstat_time st_btime; /* file creation time */
> + unsigned long long st_ino; /* inode number */
> + unsigned long long st_size; /* file size */
> + unsigned long long st_blksize; /* block size for filesystem I/O */
> + unsigned long long st_blocks; /* number of 512-byte blocks allocated */
> + unsigned long long st_gen; /* inode generation number */
> + unsigned long long st_data_version; /* data version number */
> + unsigned long long st_result_mask; /* what requests were written */
> + unsigned long long st_extra_results[0]; /* extra requested results */
> +};
> +
> #ifdef __KERNEL__
> #define S_IRWXUGO (S_IRWXU|S_IRWXG|S_IRWXO)
> #define S_IALLUGO (S_ISUID|S_ISGID|S_ISVTX|S_IRWXUGO)
> @@ -67,14 +160,20 @@ struct kstat {
> uid_t uid;
> gid_t gid;
> dev_t rdev;
> + unsigned int query_flags; /* operational flags */
> +#define KSTAT_QUERY_FLAGS (AT_FORCE_ATTR_SYNC)
> 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 request_mask; /* what fields the user asked for */
> + u64 result_mask; /* what fields the user got */
> + u64 gen; /* inode generation */
> + u64 data_version;
> };
>
> #endif
> -
> #endif
> diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
> index 8812a63..5d68b4c 100644
> --- a/include/linux/syscalls.h
> +++ b/include/linux/syscalls.h
> @@ -44,6 +44,8 @@ struct shmid_ds;
> struct sockaddr;
> struct stat;
> struct stat64;
> +struct xstat_parameters;
> +struct xstat;
> struct statfs;
> struct statfs64;
> struct __sysctl_args;
> @@ -824,4 +826,11 @@ asmlinkage long sys_mmap_pgoff(unsigned long addr, unsigned long len,
> unsigned long fd, unsigned long pgoff);
> asmlinkage long sys_old_mmap(struct mmap_arg_struct __user *arg);
>
> +asmlinkage long sys_xstat(int, const char __user *, unsigned,
> + struct xstat_parameters __user *,
> + struct xstat __user *, size_t);
> +asmlinkage long sys_fxstat(unsigned, unsigned,
> + struct xstat_parameters __user *,
> + struct xstat __user *, size_t);
> +
> #endif
>
> --
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>
--
Michael Kerrisk Linux man-pages maintainer;
http://www.kernel.org/doc/man-pages/
Author of "The Linux Programming Interface", http://blog.man7.org/
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