xref: /freebsd/sbin/fsck_ffs/fsck_ffs.8 (revision 1e413cf93298b5b97441a21d9a50fdcd0ee9945e)
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29.\"	@(#)fsck.8	8.4 (Berkeley) 5/9/95
30.\" $FreeBSD$
31.\"
32.Dd April 24, 2001
33.Dt FSCK_FFS 8
34.Os
35.Sh NAME
36.Nm fsck_ffs ,
37.Nm fsck_ufs
38.Nd file system consistency check and interactive repair
39.Sh SYNOPSIS
40.Nm
41.Op Fl BFpfny
42.Op Fl b Ar block
43.Op Fl c Ar level
44.Op Fl m Ar mode
45.Ar filesystem
46.Ar ...
47.Sh DESCRIPTION
48The specified disk partitions and/or file systems are checked.
49In "preen" mode the clean flag of each file system's superblock is examined
50and only those file systems that
51are not marked clean are checked.
52File systems are marked clean when they are unmounted,
53when they have been mounted read-only, or when
54.Nm
55runs on them successfully.
56If the
57.Fl f
58option is specified, the file systems
59will be checked regardless of the state of their clean flag.
60.Pp
61The kernel takes care that only a restricted class of innocuous file system
62inconsistencies can happen unless hardware or software failures intervene.
63These are limited to the following:
64.Pp
65.Bl -item -compact -offset indent
66.It
67Unreferenced inodes
68.It
69Link counts in inodes too large
70.It
71Missing blocks in the free map
72.It
73Blocks in the free map also in files
74.It
75Counts in the super-block wrong
76.El
77.Pp
78These are the only inconsistencies that
79.Nm
80with the
81.Fl p
82option will correct; if it encounters other inconsistencies, it exits
83with an abnormal return status and an automatic reboot will then fail.
84For each corrected inconsistency one or more lines will be printed
85identifying the file system on which the correction will take place,
86and the nature of the correction.
87After successfully correcting a file system,
88.Nm
89will print the number of files on that file system,
90the number of used and free blocks,
91and the percentage of fragmentation.
92.Pp
93If sent a
94.Dv QUIT
95signal,
96.Nm
97will finish the file system checks, then exit with an abnormal
98return status that causes an automatic reboot to fail.
99This is useful when you want to finish the file system checks during an
100automatic reboot,
101but do not want the machine to come up multiuser after the checks complete.
102.Pp
103If
104.Nm
105receives a
106.Dv SIGINFO
107(see the
108.Dq status
109argument for
110.Xr stty 1 )
111signal, a line will be written to the standard output indicating
112the name of the device currently being checked, the current phase
113number and phase-specific progress information.
114.Pp
115Without the
116.Fl p
117option,
118.Nm
119audits and interactively repairs inconsistent conditions for file systems.
120If the file system is inconsistent the operator is prompted for concurrence
121before each correction is attempted.
122It should be noted that some of the corrective actions which are not
123correctable under the
124.Fl p
125option will result in some loss of data.
126The amount and severity of data lost may be determined from the diagnostic
127output.
128The default action for each consistency correction
129is to wait for the operator to respond
130.Li yes
131or
132.Li no .
133If the operator does not have write permission on the file system
134.Nm
135will default to a
136.Fl n
137action.
138.Pp
139The following flags are interpreted by
140.Nm :
141.Bl -tag -width indent
142.It Fl F
143Determine whether the file system needs to be cleaned immediately
144in foreground, or if its cleaning can be deferred to background.
145To be eligible for background cleaning it must have been running
146with soft updates, not have been marked as needing a foreground check,
147and be mounted and writable when the background check is to be done.
148If these conditions are met, then
149.Nm
150exits with a zero exit status.
151Otherwise it exits with a non-zero exit status.
152If the file system is clean,
153it will exit with a non-zero exit status so that the clean status
154of the file system can be verified and reported during the foreground
155checks.
156Note that when invoked with the
157.Fl F
158flag, no cleanups are done.
159The only thing that
160.Nm
161does is to determine whether a foreground or background
162check is needed and exit with an appropriate status code.
163.It Fl B
164A check is done on the specified and possibly active file system.
165The set of corrections that can be done is limited to those done
166when running in preen mode (see the
167.Fl p
168flag).
169If unexpected errors are found,
170the file system is marked as needing a foreground check and
171.Nm
172exits without attempting any further cleaning.
173.It Fl b
174Use the block specified immediately after the flag as
175the super block for the file system.
176An alternate super block is usually located at block 32 for UFS1,
177and block 160 for UFS2.
178.It Fl c
179Convert the file system to the specified level.
180Note that the level of a file system can only be raised.
181There are currently four levels defined:
182.Bl -tag -width indent
183.It 0
184The file system is in the old (static table) format.
185.It 1
186The file system is in the new (dynamic table) format.
187.It 2
188The file system supports 32-bit uid's and gid's,
189short symbolic links are stored in the inode,
190and directories have an added field showing the file type.
191.It 3
192If maxcontig is greater than one,
193build the free segment maps to aid in finding contiguous sets of blocks.
194If maxcontig is equal to one, delete any existing segment maps.
195.El
196.Pp
197In interactive mode,
198.Nm
199will list the conversion to be made
200and ask whether the conversion should be done.
201If a negative answer is given,
202no further operations are done on the file system.
203In preen mode,
204the conversion is listed and done if
205possible without user interaction.
206Conversion in preen mode is best used when all the file systems
207are being converted at once.
208The format of a file system can be determined from the
209first line of output from
210.Xr dumpfs 8 .
211.It Fl f
212Force
213.Nm
214to check
215.Sq clean
216file systems when preening.
217.It Fl m
218Use the mode specified in octal immediately after the flag as the
219permission bits to use when creating the
220.Pa lost+found
221directory rather than the default 1777.
222In particular, systems that do not wish to have lost files accessible
223by all users on the system should use a more restrictive
224set of permissions such as 700.
225.It Fl n
226Assume a no response to all questions asked by
227.Nm
228except for
229.Ql CONTINUE? ,
230which is assumed to be affirmative;
231do not open the file system for writing.
232.It Fl p
233Preen file systems (see above).
234.It Fl y
235Assume a yes response to all questions asked by
236.Nm ;
237this should be used with great caution as this is a free license
238to continue after essentially unlimited trouble has been encountered.
239.El
240.Pp
241Inconsistencies checked are as follows:
242.Pp
243.Bl -enum -compact
244.It
245Blocks claimed by more than one inode or the free map.
246.It
247Blocks claimed by an inode outside the range of the file system.
248.It
249Incorrect link counts.
250.It
251Size checks:
252.Bl -item -offset indent -compact
253.It
254Directory size not a multiple of DIRBLKSIZ.
255.It
256Partially truncated file.
257.El
258.It
259Bad inode format.
260.It
261Blocks not accounted for anywhere.
262.It
263Directory checks:
264.Bl -item -offset indent -compact
265.It
266File pointing to unallocated inode.
267.It
268Inode number out of range.
269.It
270Directories with unallocated blocks (holes).
271.It
272Dot or dot-dot not the first two entries of a directory
273or having the wrong inode number.
274.El
275.It
276Super Block checks:
277.Bl -item -offset indent -compact
278.It
279More blocks for inodes than there are in the file system.
280.It
281Bad free block map format.
282.It
283Total free block and/or free inode count incorrect.
284.El
285.El
286.Pp
287Orphaned files and directories (allocated but unreferenced) are,
288with the operator's concurrence, reconnected by
289placing them in the
290.Pa lost+found
291directory.
292The name assigned is the inode number.
293If the
294.Pa lost+found
295directory does not exist, it is created.
296If there is insufficient space its size is increased.
297.Sh FILES
298.Bl -tag -width /etc/fstab -compact
299.It Pa /etc/fstab
300contains default list of file systems to check.
301.El
302.Sh EXIT STATUS
303.Ex -std
304.Sh DIAGNOSTICS
305The diagnostics produced by
306.Nm
307are fully enumerated and explained in Appendix A of
308.Rs
309.%T "Fsck \- The UNIX File System Check Program"
310.Re
311.Sh SEE ALSO
312.Xr fs 5 ,
313.Xr fstab 5 ,
314.Xr fsck 8 ,
315.Xr fsdb 8 ,
316.Xr newfs 8 ,
317.Xr reboot 8
318