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STATFS(2) | Linux Programmer's Manual | STATFS(2) |
NAME¶
statfs, fstatfs - get filesystem statisticsSYNOPSIS¶
#include <sys/vfs.h> /* or <sys/statfs.h> */ int statfs(const char *path, struct statfs *buf);DESCRIPTION¶
The function statfs() 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:#if __WORDSIZE == 32 /* System word size */ # define __SWORD_TYPE int #else /* __WORDSIZE == 64 */ # define __SWORD_TYPE long int #endif struct statfs { __SWORD_TYPE f_type; /* type of filesystem (see below) */ __SWORD_TYPE f_bsize; /* optimal transfer block size */ fsblkcnt_t f_blocks; /* total data blocks in filesystem */ fsblkcnt_t f_bfree; /* free blocks in fs */ 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 fs */ fsid_t f_fsid; /* filesystem id */ __SWORD_TYPE f_namelen; /* maximum length of filenames */ __SWORD_TYPE f_frsize; /* fragment size (since Linux 2.6) */ __SWORD_TYPE f_spare[5]; }; Filesystem types: ADFS_SUPER_MAGIC 0xadf5 AFFS_SUPER_MAGIC 0xADFF BDEVFS_MAGIC 0x62646576 BEFS_SUPER_MAGIC 0x42465331 BFS_MAGIC 0x1BADFACE BINFMTFS_MAGIC 0x42494e4d BTRFS_SUPER_MAGIC 0x9123683E CGROUP_SUPER_MAGIC 0x27e0eb CIFS_MAGIC_NUMBER 0xFF534D42 CODA_SUPER_MAGIC 0x73757245 COH_SUPER_MAGIC 0x012FF7B7 CRAMFS_MAGIC 0x28cd3d45 DEBUGFS_MAGIC 0x64626720 DEVFS_SUPER_MAGIC 0x1373 DEVPTS_SUPER_MAGIC 0x1cd1 EFIVARFS_MAGIC 0xde5e81e4 EFS_SUPER_MAGIC 0x00414A53 EXT_SUPER_MAGIC 0x137D EXT2_OLD_SUPER_MAGIC 0xEF51 EXT2_SUPER_MAGIC 0xEF53 EXT3_SUPER_MAGIC 0xEF53 EXT4_SUPER_MAGIC 0xEF53 FUSE_SUPER_MAGIC 0x65735546 FUTEXFS_SUPER_MAGIC 0xBAD1DEA 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 /* orig. minix */ MINIX_SUPER_MAGIC2 0x138F /* 30 char minix */ MINIX2_SUPER_MAGIC 0x2468 /* minix V2 */ MINIX2_SUPER_MAGIC2 0x2478 /* minix V2, 30 char names */ MINIX3_SUPER_MAGIC 0x4d5a /* minix V3 fs, 60 char names */ MQUEUE_MAGIC 0x19800202 MSDOS_SUPER_MAGIC 0x4d44 NCP_SUPER_MAGIC 0x564c NFS_SUPER_MAGIC 0x6969 NILFS_SUPER_MAGIC 0x3434 NTFS_SB_MAGIC 0x5346544e OPENPROM_SUPER_MAGIC 0x9fa1 PIPEFS_MAGIC 0x50495045 PROC_SUPER_MAGIC 0x9fa0 PSTOREFS_MAGIC 0x6165676C QNX4_SUPER_MAGIC 0x002f QNX6_SUPER_MAGIC 0x68191122 RAMFS_MAGIC 0x858458f6 REISERFS_SUPER_MAGIC 0x52654973 ROMFS_MAGIC 0x7275 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 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
Most of these MAGIC constants are defined in /usr/include/linux/magic.h some are hardcoded in kernel sources. 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
- This call was interrupted by a signal.
- 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 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 only have <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(2), path_resolution(7)COLOPHON¶
This page is part of release 3.74 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 http://www.kernel.org/doc/man-pages/.2014-06-13 | Linux |