Tag: "gnu"

  • statfs(2) for Reiser4

    STATFS

    STATFS

    NAME


    SYNOPSIS


    DESCRIPTION


    RETURN VALUE


    ERRORS


    CONFORMING TO


    NOTES


    BUGS


    SEE ALSO


    COLOPHON



    NAME

    statfs, fstatfs - get filesystem statistics

    SYNOPSIS

    #include <sys/vfs.h>    /* or <sys/statfs.h> */

    int statfs(const char *path, struct statfs *buf);
    int fstatfs(int
    fd, struct statfs *buf);

    DESCRIPTION

    The statfs() system call returns information about a mounted filesystem. path is the pathname of any file within the mounted filesystem. buf is a pointer to a statfs structure defined approximately as follows:

    struct statfs {

    __fsword_t f_type;          /* Type of filesystem (see below) */
    __fsword_t f_bsize;        /* Optimal transfer block size */
    fsblkcnt_t f_blocks;        /* Total data blocks in filesystem */

    fsblkcnt_t f_bfree;            /* Free blocks in filesystem */
    fsblkcnt_t f_bavail;           /* Free blocks available to unprivileged user */
    fsfilcnt_t f_files;                /* Total file nodes in filesystem */

    fsfilcnt_t f_ffree;                /* Free file nodes in filesystem */
    fsid_t f_fsid;                        /* Filesystem ID */
    __fsword_t f_namelen;    /* Maximum length of filenames */
    __fsword_t f_frsize;          /* Fragment size (since Linux 2.6) */

    __fsword_t f_flags;            /* Mount flags of filesystem (since Linux 2.6.36) */
    __fsword_t f_spare[xxx];
                                                    /* Padding bytes reserved for future use */
    };

    The following filesystem types may appear in f_type:

    ADFS_SUPER_MAGIC

    0xadf5

    AFFS_SUPER_MAGIC

    0xadff

    AFS_SUPER_MAGIC

    0x5346414f

    ANON_INODE_FS_MAGIC

    0x09041934    /* Anonymous inode FS (for pseudofiles that have no name; e.g., epoll, signalfd, bpf) */

    AUTOFS_SUPER_MAGIC

    0x0187

    BDEVFS_MAGIC

    0x62646576

    BEFS_SUPER_MAGIC

    0x42465331

    BFS_MAGIC

    0x1badface

    BINFMTFS_MAGIC

    0x42494e4d

    BPF_FS_MAGIC

    0xcafe4a11

    BTRFS_SUPER_MAGIC

    0x9123683e

    BTRFS_TEST_MAGIC

    0x73727279

    CGROUP_SUPER_MAGIC

    0x27e0eb    /* Cgroup pseudo FS */

    CGROUP2_SUPER_MAGIC

    0x63677270    /* Cgroup v2 pseudo FS */

    CIFS_MAGIC_NUMBER

    0xff534d42

    CODA_SUPER_MAGIC

    0x73757245

    COH_SUPER_MAGIC

    0x012ff7b7

    CRAMFS_MAGIC

    0x28cd3d45

    DEBUGFS_MAGIC

    0x64626720

    DEVFS_SUPER_MAGIC

    0x1373    /* Linux 2.6.17 and earlier */

    DEVPTS_SUPER_MAGIC

    0x1cd1

    ECRYPTFS_SUPER_MAGIC

    0xf15f

    EFIVARFS_MAGIC

    0xde5e81e4

    EFS_SUPER_MAGIC

    0x00414a53

    EXT_SUPER_MAGIC

    0x137d    /* Linux 2.0 and earlier */

    EXT2_OLD_SUPER_MAGIC

    0xef51

    EXT2_SUPER_MAGIC

    0xef53

    EXT3_SUPER_MAGIC

    0xef53

    EXT4_SUPER_MAGIC

    0xef53

    F2FS_SUPER_MAGIC

    0xf2f52010

    FUSE_SUPER_MAGIC

    0x65735546

    FUTEXFS_SUPER_MAGIC

    0xbad1dea    /* Unused */

    HFS_SUPER_MAGIC

    0x4244

    HOSTFS_SUPER_MAGIC

    0x00c0ffee

    HPFS_SUPER_MAGIC

    0xf995e849

    HUGETLBFS_MAGIC

    0x958458f6

    ISOFS_SUPER_MAGIC

    0x9660

    JFFS2_SUPER_MAGIC

    0x72b6

    JFS_SUPER_MAGIC

    0x3153464a

    MINIX_SUPER_MAGIC

    0x137f    /* original minix FS */

    MINIX_SUPER_MAGIC2

    0x138f    /* 30 char minix FS */

    MINIX2_SUPER_MAGIC

    0x2468    /* minix V2 FS */

    MINIX2_SUPER_MAGIC2

    0x2478    /* minix V2 FS, 30 char names */

    MINIX3_SUPER_MAGIC

    0x4d5a    /* minix V3 FS, 60 char names */

    MQUEUE_MAGIC

    0x19800202    /* POSIX message queue FS */

    MSDOS_SUPER_MAGIC

    0x4d44

    MTD_INODE_FS_MAGIC

    0x11307854

    NCP_SUPER_MAGIC

    0x564c

    NFS_SUPER_MAGIC

    0x6969

    NILFS_SUPER_MAGIC

    0x3434

    NSFS_MAGIC

    0x6e736673

    NTFS_SB_MAGIC

    0x5346544e

    OCFS2_SUPER_MAGIC

    0x7461636f

    OPENPROM_SUPER_MAGIC

    0x9fa1

    OVERLAYFS_SUPER_MAGIC

    0x794c7630

    PIPEFS_MAGIC

    0x50495045

    PROC_SUPER_MAGIC

    0x9fa0    /* /proc FS */

    PSTOREFS_MAGIC

    0x6165676c

    QNX4_SUPER_MAGIC

    0x002f

    QNX6_SUPER_MAGIC

    0x68191122

    RAMFS_MAGIC

    0x858458f6

    REISERFS_SUPER_MAGIC

    0x52654973

    REISER4_SUPER_MAGIC

    0x52345362

    ROMFS_MAGIC

    0x7275

    SECURITYFS_MAGIC

    0x73636673

    SELINUX_MAGIC

    0xf97cff8c

    SMACK_MAGIC

    0x43415d53

    SMB_SUPER_MAGIC

    0x517b

    SOCKFS_MAGIC

    0x534f434b

    SQUASHFS_MAGIC

    0x73717368

    SYSFS_MAGIC

    0x62656572

    SYSV2_SUPER_MAGIC

    0x012ff7b6

    SYSV4_SUPER_MAGIC

    0x012ff7b5

    TMPFS_MAGIC

    0x01021994

    TRACEFS_MAGIC

    0x74726163

    UDF_SUPER_MAGIC

    0x15013346

    UFS_MAGIC

    0x00011954

    USBDEVICE_SUPER_MAGIC

    0x9fa2

    V9FS_MAGIC

    0x01021997

    VXFS_SUPER_MAGIC

    0xa501fcf5

    XENFS_SUPER_MAGIC

    0xabba1974

    XENIX_SUPER_MAGIC

    0x012ff7b4

    XFS_SUPER_MAGIC

    0x58465342

    _XIAFS_SUPER_MAGIC

    0x012fd16d    /* Linux 2.0 and earlier */







    Most of these MAGIC constants are defined in /usr/include/linux/magic.h, and some are hardcoded in kernel sources.

    The f_flags field is a bit mask indicating mount optionsfor the filesystem. It contains zero or more of the following bits:
    ST_MANDLOCK

    Mandatory locking is permitted on the filesystem (see fcntl(2)).

    ST_NOATIME

    Do not update access times; see mount(2).

    ST_NODEV

    Disallow access to device special files on this filesystem.

    ST_NODIRATIME

    Do not update directory access times; see mount(2).

    ST_NOEXEC

    Execution of programs is disallowed on this filesystem.

    ST_NOSUID

    The set-user-ID and set-group-ID bits are ignored by exec(3) for executable files on this filesystem

    ST_RDONLY

    This filesystem is mounted read-only.

    ST_RELATIME

    Update atime relative to mtime/ctime; see mount(2).

    ST_SYNCHRONOUS

    Writes are synched to the filesystem immediately (see the description of O_SYNC in open(2)).

    Nobody knows what f_fsid is supposed to contain (but see below).

    Fields that are undefined for a particular filesystem are set to 0.

    fstatfs() returns the same information about an open file referenced by descriptor fd.

    RETURN VALUE

    On success, zero is returned. On error, -1 is returned, and errno is set appropriately.

    ERRORS

    EACCES

    (statfs()) Search permission is denied for a component of the path prefix of path. (See also path_resolution(7).)

    EBADF

    (fstatfs()) fd is not a valid open file descriptor.

    EFAULT

    buf or path points to an invalid address.

    EINTR

    The call was interrupted by a signal; see signal(7).

    EIO

    An I/O error occurred while reading from the filesystem.

    ELOOP

    (statfs()) Too many symbolic links were encountered in translating path.

    ENAMETOOLONG

    (statfs()) path is too long.

    ENOENT

    (statfs()) The file referred to by path does not exist.

    ENOMEM

    Insufficient kernel memory was available.

    ENOSYS

    The filesystem does not support this call.

    ENOTDIR

    (statfs()) A component of the path prefix of path is not a directory.

    EOVERFLOW

    Some values were too large to be represented in the returned struct.

    CONFORMING TO

    Linux-specific. The Linux statfs() was inspired by the 4.4BSD one (but they do not use the same structure).

    NOTES

    The __fsword_t type used for various fields in the statfs structure definition is a glibc internal type, not intended for public use. This leaves the programmer in a bit of a conundrum when trying to copy or compare these fields to local variables in a program. Using unsigned int for such variables suffices on most systems.

    The original Linux statfs() and fstatfs() system calls were not designed with extremely large file sizes in mind. Subsequently, Linux 2.6 added new statfs64() and fstatfs64() system calls that employ a new structure, statfs64. The new structure contains the same fields as the original statfs structure, but the sizes of various fields are increased, to accommodate large file sizes. The glibc statfs() and fstatfs() wrapper functions transparently deal with the kernel differences.


    Some systems have only <sys/vfs.h>, other systems also have <sys/statfs.h>, where the former includes the latter. So it seems including the former is the best choice.

    LSB has deprecated the library calls statfs() and fstatfs() and tells us to use statvfs(2) and fstatvfs(2) instead.

    The f_fsid field
    Solaris, Irix and POSIX have a system call statvfs(2) that returns a struct statvfs (defined in <sys/statvfs.h>) containing an unsigned long f_fsid. Linux, SunOS, HP-UX, 4.4BSD have a system call statfs() that returns a struct statfs (defined in <sys/vfs.h>) containing a fsid_t f_fsid, where fsid_t is defined as struct { int val[2]; }. The same holds for FreeBSD, except that it uses the include file <sys/mount.h>.

    The general idea is that f_fsid contains some random stuff such that the pair (f_fsid,ino) uniquely determines a file. Some operating systems use (a variation on) the device number, or the device number combined with the filesystem type. Several operating systems restrict giving out the f_fsid field to the superuser only (and zero it for unprivileged users), because this field is used in the filehandle of the filesystem when NFS-exported, and giving it out is a security concern.

    Under some operating systems, the fsid can be used as the second argument to the sysfs(2) system call.

    BUGS

    From Linux 2.6.38 up to and including Linux 3.1, fstatfs() failed with the error ENOSYS for file descriptors created by pipe(2).

    SEE ALSO

    stat(2), statvfs(3), path_resolution(7)

    COLOPHON

    This page is part of release 4.16 of the Linux man-pages project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at https://www.kernel.org/doc/man-pages/.


    References:
    Converting a man page to HTML, PDF, text
    Unicode Character “x” (U+0078)

    Metztli Reiser4 / Debian Buster:

    Shell

    apt-get update
    apt-get install groff
    cp -iv /usr/share/man/man2/statfs.2.gz /usr/share/man/man2/statfs.2.gzBkUp
    gzip -/usr/share/man/man2/statfs.2.gz
    sed -'/^REISERFS.*/a REISER4_SUPER_MAGIC   0x52345362' /usr/share/man/man2/statfs.2
    cat /usr/share/man/man2/statfs.2 groff -mandoc -Thtml >man_statfs.2.html
    gzip -/usr/share/man/man2/statfs.2
    man 2 statfs