statvfs(2) statvfs(2)
statvfs, fstatvfs, statvfs64, fstatvfs64 - get file system information
#include <sys/types.h>
#include <sys/statvfs.h>
int statvfs (const char *path, struct statvfs *buf);
int statvfs64 (const char *path, struct statvfs64 *buf);
int fstatvfs (int fildes, struct statvfs *buf);
int fstatvfs64 (int fildes, struct statvfs64 *buf);
statvfs returns a ``generic superblock'' describing a file system; it can
be used to acquire information about mounted file systems. buf is a
pointer to a structure (described below) that is filled by the system
call.
path should name a file that resides on that file system. The file
system type is known to the operating system. Read, write, or execute
permission for the named file is not required, but all directories listed
in the path name leading to the file must be searchable.
The statvfs structure pointed to by buf includes the following members:
ulong_t f_bsize; /* preferred file system block size */
ulong_t f_frsize; /* fundamental filesystem block size
(if supported) */
ulong_t f_blocks; /* total # of blocks on file system
in units of f_frsize */
ulong_t f_bfree; /* total # of free blocks */
ulong_t f_bavail; /* # of free blocks avail to
non-superuser */
ulong_t f_files; /* total # of file nodes (inodes) */
ulong_t f_ffree; /* total # of free file nodes */
ulong_t f_favail; /* # of inodes avail to
non-superuser */
ulong_t f_fsid; /* file system id (dev for now) */
char f_basetype[FSTYPSZ]; /* target file system type name,
null-terminated */
ulong_t f_flag; /* bit mask of flags */
ulong_t f_namemax; /* maximum file name length */
char f_fstr[32]; /* file system specific string */
ulong_t f_filler[16]; /* reserved for future expansion */
f_basetype contains a null-terminated FSType name of the mounted target
(e.g. iso9660 mounted over nfs will contain iso9660).
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statvfs(2) statvfs(2)
The following flags can be returned in the f_flag field:
ST_RDONLY 0x00000001 /* read-only file system */
ST_NOSUID 0x00000002 /* does not support setuid/setgid
semantics */
ST_NOTRUNC 0x00000004 /* does not truncate file names
longer than {NAME_MAX} */
ST_NODEV 0x20000000 /* disallow opening of device files */
ST_GRPID 0x40000000 /* group-ID assigned from directory */
ST_LOCAL 0x80000000 /* local filesystem, for find */
fstatvfs is similar to statvfs, except that the file named by path in
statvfs is instead identified by an open file descriptor fildes obtained
from a successful open, creat, dup, fcntl, or pipe system call.
statvfs64 and fstatvfs64 are similar to statvfs and fstatvfs
respectively, except that the structure fields f_blocks, f_bfree,
f_bavail, f_files, f_ffree, and f_favail are 64-bit values instead of
ulong_ts. The block-count fields are of type blkcnt_t and the file-count
fields are of type filcnt_t. These fields can normally overflow in a
non-64-bit call only in a 32-bit application on an XFS filesystem whose
size is larger than 1 terabyte.
For XFS filesystems with real-time subvolumes (see xfs(4)), the
statvfs(2) system call returns information concerning the data portion of
the filesystem only. The syssgi(2) system call with the
SGI_XFS_FSOPERATIONS request argument can be used to acquire information
concerning the size and usage of space within the real-time portion of
the filesystem.
The ST_LOCAL flag is off for regular files which are also swap files,
since they cannot be read even if permissions allow it. This allows
programs to detect this situation without trying to read data from such
files.
statvfs fails if one or more of the following are true:
EACCES Search permission is denied on a component of the path
prefix.
EFAULT path or buf points outside the process's allocated address
space.
EINTR A signal was caught during statvfs execution.
EIO An I/O error occurred while reading the file system.
ELOOP Too many symbolic links were encountered in translating
path.
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statvfs(2) statvfs(2)
EMULTIHOP Components of path require hopping to multiple remote
machines and file system type does not allow it.
ENAMETOOLONG The length of a path component exceeds {NAME_MAX}
characters, or the length of path exceeds {PATH_MAX}
characters.
ENOENT Either a component of the path prefix or the file referred
to by path does not exist.
ENOLINK path points to a remote machine and the link to that
machine is no longer active.
ENOTDIR A component of the path prefix of path is not a directory.
fstatvfs fails if one or more of the following are true:
EFAULT buf points to an invalid address.
EBADF fildes is not an open file descriptor.
EINTR A signal was caught during fstatvfs execution.
EIO An I/O error occurred while reading the file system.
EFBIG One of the fields overflowed (did not fit in a ulong_t).
See the description of statvfs64 and fstatvfs64 above.
Upon successful completion a value of 0 is returned. Otherwise, a value
of -1 is returned and errno is set to indicate the error.
chmod(2), chown(2), creat(2), link(2), mknod(2), pipe(2), read(2),
time(2), unlink(2), utime(2), write(2).
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