NAME

biffsck − Bell file system consistency check and interactive repair

SYNOPSIS

biffsck [−y] [−n] [−snb_c:nb_s] [−Snb_c:nb_s] [−t filename] [file-system] ...

DESCRIPTION

biffsck audits and interactively repairs inconsistent conditions in a Bell file system.  If the file system is consistent, the number of files, number of blocks used, and number of blocks free are reported.  If the file system is inconsistent, the operator is prompted for concurrence before each correction is attempted.  It should be noted that most corrective actions result in some loss of data.  The amount and severity of data lost can be determined from the diagnostic output.  The default action for each consistency correction is to wait for the operator to respond yes or no.  If the operator does not have write permission, biffsck defaults to the −n option described below. 

The following flags are interpreted by biffsck.

−y Assume a yes response to all questions asked by biffsck.

−n Assume a no response to all questions asked by biffsck, and do not open the file system for writing.

−snb_c:nb_s
Ignore the actual free list and unconditionally reconstruct a new one by rewriting the super-block of the file system. The file system should be unmounted while this is done.

This option allows for creating an optimal free-list organization.  Arguments to the -s option are numerical values separated by a colon and are determined as follows:

nb_c Number of blocks per cylinder. 

nb_s Number of blocks to skip. 

If nb_c:nb_s is not specified with this option, the values used when the file system was created are used.  If no values were specified when the file system was created, the following defaults are used for the devices indicated:

−Snb_c:nb_s
Conditionally reconstruct the free list. This option is similar to −snb_c:nb_s above except that the free list is rebuilt only if there were no discrepancies discovered in the file system.  Using −S forces a no response to all questions asked by biffsck. This option is useful for forcing free list reorganization on uncontaminated Bell file systems.

−t If biffsck cannot obtain enough memory to keep its tables, it uses a scratch file. If the −t option is specified, the file named in the accompanying filename argument is used as the scratch file, if needed.  Without the −t flag, biffsck prompts the operator for the name of the scratch file.  The file chosen should not be on the file system being checked.  If the file does not exist, biffsck creates it.  If the scratch file is not a special file, it is removed when biffsck terminates. 

file-system is a device file name on which the file system to be checked resides; for example, /dev/dsk/1s0. 

biffsck checks for the following inconsistencies:

1.  Blocks claimed by more than one inode or the free list. 

2.  Blocks claimed by an inode or the free list outside the range of the file system. 

3.  Incorrect link counts. 

4.  Size checks:
Incorrect number of blocks.
Directory size not 16-byte aligned.

5.  Bad inode format. 

6.  Blocks not accounted for anywhere. 

7.  Directory checks:
File pointing to unallocated inode.
Inode number out of range.

8.  Super Block checks:
More than 65536 inodes.
More blocks for inodes than there are in the file system.

9.  Bad free block list format. 

10.  Total free block and/or free inode count incorrect. 

Orphaned files and directories (allocated but unreferenced) are, with the operator’s concurrence, reconnected by placing them in the /lost+found directory on the BIF volume.  The name assigned is the inode number.  The only restriction is that the directory lost+found must already exist in the root of the file system being checked and must have empty slots in which entries can be made.  This is accomplished by making lost+found, copying a number of files to the directory (optimally in multiples of 64), then removing them before biffsck is executed. 

biffsck can check file systems on both raw and blocked devices.  Checking raw devices is almost always faster, but should not be used on a mounted file system. 

DIAGNOSITCS

The diagnostics produced by biffsck are intended to be self-explanatory. 

WARNINGS

Inode numbers for .  and ..  in each directory should be checked for validity. 

AUTHOR

biffsck was developed by HP. 

SEE ALSO

bif(4). 

Hewlett-Packard Company  —  HP-UX Release 9.0: August 1992