Re: [PATCH 1/6] xstat: Add a pair of system calls to make extended file stats available

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. The idea was initially proposed as a set of xattrs that could be retrieved with getxattr(), but the general preferance proved to be for new syscalls with an extended stat structure. This has a number of uses: (1) Creation time: The SMB protocol carries the creation time, which could be exported by Samba, which will in turn help CIFS make use of FS-Cache as that can be used for coherency data. This is also specified in NFSv4 as a recommended attribute and could be exported by NFSD [Steve French]. (2) Lightweight stat: Ask for just those details of interest, and allow a netfs (such as NFS) to approximate anything not of interest, possibly without going to the server [Trond Myklebust, Ulrich Drepper]. (3) Heavyweight stat: Force a netfs to go to the server, even if it thinks its cached attributes are up to date [Trond Myklebust]. (4) Inode generation number: Useful for FUSE and userspace NFS servers [Bernd Schubert]. (5) Data version number: Could be used by userspace NFS servers [Aneesh Kumar]. Can also be used to modify fill_post_wcc() in NFSD which retrieves i_version directly, but has just called vfs_getattr(). It could get it from the kstat struct if it used vfs_xgetattr() instead. (6) BSD stat compatibility: Including more fields from the BSD stat such as creation time (st_btime) and inode generation number (st_gen) [Jeremy Allison, Bernd Schubert]. (7) Extra coherency data may be useful in making backups [Andreas Dilger]. (8) Allow the filesystem to indicate what it can/cannot provide: A filesystem can now say it doesn't support a standard stat feature if that isn't available, so if, for instance, inode numbers or UIDs don't exist... (9) Make the fields a consistent size on all arches and make them large. (10) Store a 16-byte volume ID in the superblock that can be returned in struct xstat [Steve French]. (11) Include granularity fields in the time data to indicate the granularity of each of the times (NFSv4 time_delta) [Steve French].

(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(a)redhat.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@andromeda ~]# /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@andromeda ~]# /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 &lt;dhowells(a)redhat.com&gt; --- 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 -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html