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Diffstat (limited to 'man/man2/statfs.2')
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1 files changed, 389 insertions, 0 deletions
diff --git a/man/man2/statfs.2 b/man/man2/statfs.2 new file mode 100644 index 000000000..ffee7ee87 --- /dev/null +++ b/man/man2/statfs.2 @@ -0,0 +1,389 @@ +.\" Copyright (C) 2003 Andries Brouwer (aeb@cwi.nl) +.\" +.\" SPDX-License-Identifier: Linux-man-pages-copyleft +.\" +.\" Modified 2003-08-17 by Walter Harms +.\" Modified 2004-06-23 by Michael Kerrisk <mtk.manpages@gmail.com> +.\" +.TH statfs 2 (date) "Linux man-pages (unreleased)" +.SH NAME +statfs, fstatfs \- get filesystem statistics +.SH LIBRARY +Standard C library +.RI ( libc ", " \-lc ) +.SH SYNOPSIS +.nf +.BR "#include <sys/vfs.h> " "/* or <sys/statfs.h> */" +.P +.BI "int statfs(const char *" path ", struct statfs *" buf ); +.BI "int fstatfs(int " fd ", struct statfs *" buf ); +.fi +.P +Unless you need the +.I f_type +field, you should use the standard +.BR statvfs (3) +interface instead. +.SH DESCRIPTION +The +.BR statfs () +system call returns information about a mounted filesystem. +.I path +is the pathname of any file within the mounted filesystem. +.I buf +is a pointer to a +.I statfs +structure defined approximately as follows: +.P +.in +4n +.EX +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 inodes in filesystem */ + fsfilcnt_t f_ffree; /* Free inodes 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 */ +}; +.EE +.in +.P +The following filesystem types may appear in +.IR f_type : +.P +.in +4n +.EX +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 +ROMFS_MAGIC 0x7275 +SECURITYFS_MAGIC 0x73636673 +SELINUX_MAGIC 0xf97cff8c +SMACK_MAGIC 0x43415d53 +SMB_SUPER_MAGIC 0x517b +SMB2_MAGIC_NUMBER 0xfe534d42 +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 */ +.EE +.in +.P +Most of these MAGIC constants are defined in +.IR /usr/include/linux/magic.h , +and some are hardcoded in kernel sources. +.P +The +.I f_flags +field is a bit mask indicating mount options for the filesystem. +It contains zero or more of the following bits: +.\" XXX Keep this list in sync with statvfs(3) +.TP +.B ST_MANDLOCK +Mandatory locking is permitted on the filesystem (see +.BR fcntl (2)). +.TP +.B ST_NOATIME +Do not update access times; see +.BR mount (2). +.TP +.B ST_NODEV +Disallow access to device special files on this filesystem. +.TP +.B ST_NODIRATIME +Do not update directory access times; see +.BR mount (2). +.TP +.B ST_NOEXEC +Execution of programs is disallowed on this filesystem. +.TP +.B ST_NOSUID +The set-user-ID and set-group-ID bits are ignored by +.BR exec (3) +for executable files on this filesystem +.TP +.B ST_RDONLY +This filesystem is mounted read-only. +.TP +.B ST_RELATIME +Update atime relative to mtime/ctime; see +.BR mount (2). +.TP +.B ST_SYNCHRONOUS +Writes are synched to the filesystem immediately (see the description of +.B O_SYNC +in +.BR open (2)). +.TP +.BR ST_NOSYMFOLLOW " (since Linux 5.10)" +.\" dab741e0e02bd3c4f5e2e97be74b39df2523fc6e +Symbolic links are not followed when resolving paths; see +.BR mount (2). +.P +Nobody knows what +.I f_fsid +is supposed to contain (but see below). +.P +Fields that are undefined for a particular filesystem are set to 0. +.P +.BR fstatfs () +returns the same information about an open file referenced by descriptor +.IR fd . +.SH RETURN VALUE +On success, zero is returned. +On error, \-1 is returned, and +.I errno +is set to indicate the error. +.SH ERRORS +.TP +.B EACCES +.RB ( statfs ()) +Search permission is denied for a component of the path prefix of +.IR path . +(See also +.BR path_resolution (7).) +.TP +.B EBADF +.RB ( fstatfs ()) +.I fd +is not a valid open file descriptor. +.TP +.B EFAULT +.I buf +or +.I path +points to an invalid address. +.TP +.B EINTR +The call was interrupted by a signal; see +.BR signal (7). +.TP +.B EIO +An I/O error occurred while reading from the filesystem. +.TP +.B ELOOP +.RB ( statfs ()) +Too many symbolic links were encountered in translating +.IR path . +.TP +.B ENAMETOOLONG +.RB ( statfs ()) +.I path +is too long. +.TP +.B ENOENT +.RB ( statfs ()) +The file referred to by +.I path +does not exist. +.TP +.B ENOMEM +Insufficient kernel memory was available. +.TP +.B ENOSYS +The filesystem does not support this call. +.TP +.B ENOTDIR +.RB ( statfs ()) +A component of the path prefix of +.I path +is not a directory. +.TP +.B EOVERFLOW +Some values were too large to be represented in the returned struct. +.SH VERSIONS +.SS The f_fsid field +Solaris, Irix, and POSIX have a system call +.BR statvfs (2) +that returns a +.I "struct statvfs" +(defined in +.IR <sys/statvfs.h> ) +containing an +.I "unsigned long" +.IR f_fsid . +Linux, SunOS, HP-UX, 4.4BSD have a system call +.BR statfs () +that returns a +.I "struct statfs" +(defined in +.IR <sys/vfs.h> ) +containing a +.I fsid_t +.IR f_fsid , +where +.I fsid_t +is defined as +.IR "struct { int val[2]; }" . +The same holds for FreeBSD, except that it uses the include file +.IR <sys/mount.h> . +.P +The general idea is that +.I f_fsid +contains some random stuff such that the pair +.RI ( 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 +.I 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. +.P +Under some operating systems, the +.I fsid +can be used as the second argument to the +.BR sysfs (2) +system call. +.SH STANDARDS +Linux. +.SH HISTORY +The Linux +.BR statfs () +was inspired by the 4.4BSD one +(but they do not use the same structure). +.P +The original Linux +.BR statfs () +and +.BR fstatfs () +system calls were not designed with extremely large file sizes in mind. +Subsequently, Linux 2.6 +added new +.BR statfs64 () +and +.BR fstatfs64 () +system calls that employ a new structure, +.IR statfs64 . +The new structure contains the same fields as the original +.I statfs +structure, but the sizes of various fields are increased, +to accommodate large file sizes. +The glibc +.BR statfs () +and +.BR fstatfs () +wrapper functions transparently deal with the kernel differences. +.P +LSB has deprecated the library calls +.BR statfs () +and +.BR fstatfs () +and tells us to use +.BR statvfs (3) +and +.BR fstatvfs (3) +instead. +.SH NOTES +The +.I __fsword_t +type used for various fields in the +.I 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 +.I "unsigned\ int" +for such variables suffices on most systems. +.P +Some systems have only \fI<sys/vfs.h>\fP, other systems also have +\fI<sys/statfs.h>\fP, where the former includes the latter. +So it seems +including the former is the best choice. +.SH BUGS +From Linux 2.6.38 up to and including Linux 3.1, +.\" broken in commit ff0c7d15f9787b7e8c601533c015295cc68329f8 +.\" fixed in commit d70ef97baf048412c395bb5d65791d8fe133a52b +.BR fstatfs () +failed with the error +.B ENOSYS +for file descriptors created by +.BR pipe (2). +.SH SEE ALSO +.BR stat (2), +.BR statvfs (3), +.BR path_resolution (7) |