This update implements tallying of free directory entries during
create, delete, or rename operations on FAT12 and FAT16 file systems.
Prior to this change, the total number of root directory entries
was reported as number of inodes, but 0 as the number of free
inodes, causing system health monitoring software to warn about
a suspected disk full issue.
The FAT12 and FAT16 file systems provide a limited number of
root directory entries, e.g. 512 on typical hard disk formats.
The valid range of values is 1 to 65535, but the msdosfs code
will effectively round up "odd" values to the next multiple of 16
(e.g. 513 would allow for 528 root directory entries).
This update implements tracking of directory entries during create,
delete, or rename operations, with initial values determined by
scanning the directory when the file system is mounted.
Total and free directory entries are reported in the f_files and
f_ffree elements of struct statfs, despite differences in semantics
of these values:
- There is no limit on the number of files and directories that can
be created on a FAT file system. Only the root directory of FAT12
and FAT16 file systems is limited, any number of files can still be
created in sub-directories, even when 0 free "inodes" are reported.
- A single file can require 1 to 21 directory entries, depending on
the character set, structure, and length of the name. The DOS 8.3
style file name takes up 1 entry, and if the name does not comply
with the syntax of a DOS 8.3 file name, 1 additional entry is used
for each 13 characters of the file name. Since all these entries
have to be contiguous, it is possible that a file or directory with
a long name can not be created, despite a sufficient total number of
free directory entries.
- Renaming a file can require more directory entries than currently
allocated to store its long name, which may prevent an in-place
update of the name if more entries are needed. This may cause a
rename operation to fail if no contiguous range of free entries for
the new name can be found.
- The volume label is stored in a directory entry. An empty FAT file
system with a volume label will therefore show 1 used "inode" in
df.
- The perceentage of free inodes shown in df or monitoring tools does
only represent the state of the root directory of a FAT12 or FAT16
file system. Neither does a reported value of 0% free inodes does
prevent files from being created in sub-directories, nor does a
value of 50% free inodes guarantee that even a single file with
a "long" name can be created in the root directory (if every other
directory entry is occupied and there are no 2 contiguous entries).
The statfs(2) and df(1) man pages have been updated with a notice
regarding the possibly different semantics of values reported as
total and free inodes for non-Unix file systems.
PR: 270053
Reported by: Ben Woods <woodsb02@freebsd.org>
Approved by: mckusick
MFC after: 1 month
Differential Revision: https://reviews.freebsd.org/D38987
Before:
devfs 2 2 0 100% 0 0 100% /dev
After:
devfs 2 2 0 100% 0 0 - /dev
The previous behaviour was confusing for end users and many monitoring tools
Note the linux df tools is also using the same syntax '-' for such filesystem
MFC After: 2 weeks
Reviewed by: manu, emaste, imp
Differential Revision: https://reviews.freebsd.org/D34515
The df command provides a -l option to exclude all non-local file
systems and a -t option with a (positive or negative) list of file
system types to display.
This commit adds support for a combination of -l and -t. If both are
specified, the parameter list of the -t option is applied on top of
the selection of öocal file systems (independently of the order of
the -l and -t options).
E.g., "df -t noprocfs,sysfs -l" will select all local file systems
except those of type procfs and sysfs.
PR: 260921
Approved by: imp
Relnotes: yes
MFC after: 1 month
Differential Revision: https://reviews.freebsd.org/D33748
This was marked deprecated in r329092, over two and a half years ago.
This functionality is also buggy per PR 237368.
PR: 237368
Reviewed by: brooks, cem, emaste, imp
Differential Revision: https://reviews.freebsd.org/D27197
* Add EXAMPLES section with four simple examples.
* Simplify -H flag description. This makes easy to see the difference between
this flag and -h
* While here, fix .Tn deprecated macro.
Approved by: manpages (bcr@)
Differential Revision: https://reviews.freebsd.org/D26662
Renumber cluase 4 to 3, per what everybody else did when BSD granted
them permission to remove clause 3. My insistance on keeping the same
numbering for legal reasons is too pedantic, so give up on that point.
Submitted by: Jan Schaumann <jschauma@stevens.edu>
Pull Request: https://github.com/freebsd/freebsd/pull/96
Base 10 is always used for the inode counts as I could not think of any
reason base 2 inode counts would be useful.
Minor mdoc markup fix to df(1) while here anyway.
MFC after: 3 weeks
invalid information will be printed if the -t flag is specified.
$ df -t ufs
Filesystem 1K-blocks Used Avail Capacity Mounted on
/dev/ad0s1a 495726 139944 316124 31% /
/dev/ad0s1e 253678 6438 226946 3% /tmp
/dev/ad0s1f 56206340 13594248 38115586 26% /usr
/dev/ad0s1d 694126 19812 618784 3% /var
/dev/ad0s1d 694126 19812 618784 3% /var
$
Note that the mount point which is not accessible shows
up as the previous file system that was printed. The reason
for this is that df -t will call statfs(2) on the pathname
supplied by getfsstat(2).
This is done to refresh the file system statistics in the
event that a previous file system had a long delay in
providing its stats.
This change affects the df utility in the following ways:
o Teach df has to deal with statfs(2) failing. If statfs(2)
fails, fall back on the possibly stale stats provided by
the initial call to getfsstat(2).
o Print a warning that the fs stats could possibly be stale
o Modify the man page and document this new behavior
as a bug.
Approved by: bmilekic (mentor)
PR: 68165
Obtained from: parts of human readable code from OpenBSD
Reviewed by: obrien
add POSIX, byte and megabyte block size ouput flags
PR: 13579 (POSIX flag)
Submitted by: Mike Meyer <mwm@phone.net>
be ignored by default by the df(1) program. This is used mostly to
avoid stat()-ing entries that do not represent "real" disk mount
points (such as those made by an automounter such as amd.) It is
also useful not to have to stat() these entries because it takes
longer to report them that for other file systems, being that these
mount points are served by a user-level file server and resulting in
several context switches. Worse, if the automounter is down
unexpectedly, a causal df(1) will hang in an interruptible way.
PR: kern/9764
Submitted by: Erez Zadok <ezk@cs.columbia.edu>
