xfs_db(8) System Manager's Manual xfs_db(8)
NAME
xfs_db - debug an XFS filesystem
SYNOPSIS
xfs_db [ -c cmd ] ... [ -i|r|x|F ] [ -f ] [ -l logdev ] [ -R rtdev ] [
-p progname ] device
xfs_db -V
DESCRIPTION
xfs_db is used to examine an XFS filesystem. Under rare circumstances it
can also be used to modify an XFS filesystem, but that task is normally
left to xfs_repair(8) or to scripts such as xfs_admin(8) that run
xfs_db.
OPTIONS
-c cmd xfs_db commands may be run interactively (the default) or as ar-
guments on the command line. Multiple -c arguments may be given.
The commands are run in the sequence given, then the program ex-
its.
-f Specifies that the filesystem image to be processed is stored in
a regular file at device (see the mkfs.xfs(8) -d file option).
This might happen if an image copy of a filesystem has been made
into an ordinary file with xfs_copy(8).
-F Specifies that we want to continue even if the superblock magic
is not correct. For use in xfs_metadump.
-i Allows execution on a mounted filesystem, provided it is mounted
read-only. Useful for shell scripts which must only operate on
filesystems in a guaranteed consistent state (either unmounted or
mounted read-only). These semantics are slightly different to
that of the -r option.
-l logdev
Specifies the device where the filesystems external log resides.
Only for those filesystems which use an external log. See the
mkfs.xfs(8) -l option, and refer to xfs(5) for a detailed de-
scription of the XFS log.
-p progname
Set the program name to progname for prompts and some error mes-
sages, the default value is xfs_db.
-R rtdev Specifies the device where the realtime data resides. This
is only relevant for filesystems that have a realtime section.
See the mkfs.xfs(8) -r option, and refer to xfs(5) for a detailed
description of the XFS realtime section.
-r Open device or filename read-only. This option is required if the
filesystem is mounted. It is only necessary to omit this flag if
a command that changes data (write, blocktrash, crc) is to be
used.
-x Specifies expert mode. This enables the (write, blocktrash, crc
invalidate/revalidate) commands.
-V Prints the version number and exits.
CONCEPTS
xfs_db commands can be broken up into two classes. Most commands are for
the navigation and display of data structures in the filesystem. Other
commands are for scanning the filesystem in some way.
Commands which are used to navigate the filesystem structure take argu-
ments which reflect the names of filesystem structure fields. There can
be multiple field names separated by dots when the underlying structures
are nested, as in C. The field names can be indexed (as an array index)
if the underlying field is an array. The array indices can be specified
as a range, two numbers separated by a dash.
xfs_db maintains a current address in the filesystem. The granularity
of the address is a filesystem structure. This can be a filesystem
block, an inode or quota (smaller than a filesystem block), or a direc-
tory block (could be larger than a filesystem block). There are a vari-
ety of commands to set the current address. Associated with the current
address is the current data type, which is the structural type of this
data. Commands which follow the structure of the filesystem always set
the type as well as the address. Commands which examine pieces of an
individual file (inode) need the current inode to be set, this is done
with the inode command.
The current address/type information is actually maintained in a stack
that can be explicitly manipulated with the push, pop, and stack com-
mands. This allows for easy examination of a nested filesystem struc-
ture. Also, the last several locations visited are stored in a ring
buffer which can be manipulated with the forward, back, and ring com-
mands.
XFS filesystems are divided into a small number of allocation groups.
xfs_db maintains a notion of the current allocation group which is ma-
nipulated by some commands. The initial allocation group is 0.
COMMANDS
Many commands have extensive online help. Use the help command for more
details on any command.
a See the addr command.
ablock filoff
Set current address to the offset filoff (a filesystem block num-
ber) in the attribute area of the current inode.
addr [field-expression]
Set current address to the value of the field-expression. This
is used to "follow" a reference in one structure to the object
being referred to. If no argument is given, the current address
is printed.
agf [agno]
Set current address to the AGF block for allocation group agno.
If no argument is given, use the current allocation group.
agfl [agno]
Set current address to the AGFL block for allocation group agno.
If no argument is given, use the current allocation group.
agi [agno]
Set current address to the AGI block for allocation group agno.
If no argument is given, use the current allocation group.
agresv [agno]
Displays the length, free block count, per-AG reservation size,
and per-AG reservation usage for a given AG. If no argument is
given, display information for all AGs.
attr_get [-p|-r|-u|-s|-Z] [-N namefile|name]
Print the value of the specified extended attribute from the cur-
rent file.
-p Sets the attribute in the parent namespace. Only one
namespace option can be specified.
-r Sets the attribute in the root namespace. Only one name-
space option can be specified.
-u Sets the attribute in the user namespace. Only one name-
space option can be specified.
-s Sets the attribute in the secure namespace. Only one
namespace option can be specified.
-Z Sets a filesystem property in the root namespace. Only
one namespace option can be specified.
-N Read the name from this file.
attr_list [-p|-r|-u|-s|-Z] [-v]
Lists the extended attributes of the current file.
-p Sets the attribute in the parent namespace. Only one
namespace option can be specified.
-r Sets the attribute in the root namespace. Only one name-
space option can be specified.
-u Sets the attribute in the user namespace. Only one name-
space option can be specified.
-s Sets the attribute in the secure namespace. Only one
namespace option can be specified.
-Z Sets a filesystem property in the root namespace. Only
one namespace option can be specified.
-v Print the extended attribute values too.
attr_remove [-p|-r|-u|-s|-Z] [-n] [-N namefile|name]
Remove the specified extended attribute from the current file.
-p Sets the attribute in the parent namespace. Only one
namespace option can be specified.
-r Sets the attribute in the root namespace. Only one name-
space option can be specified.
-u Sets the attribute in the user namespace. Only one name-
space option can be specified.
-s Sets the attribute in the secure namespace. Only one
namespace option can be specified.
-Z Sets a filesystem property in the root namespace. Only
one namespace option can be specified.
-N Read the name from this file.
-n Do not enable 'noattr2' mode on V4 filesystems.
attr_set [-p-r|-u|-s|-Z] [-n] [-R|-C] [-v valuelen|-V valuefile] [-N
namefile|name] [value]
Sets an extended attribute on the current file with the given
name.
-p Sets the attribute in the parent namespace. Only one
namespace option can be specified.
-r Sets the attribute in the root namespace. Only one name-
space option can be specified.
-u Sets the attribute in the user namespace. Only one name-
space option can be specified.
-s Sets the attribute in the secure namespace. Only one
namespace option can be specified.
-Z Sets a filesystem property in the root namespace. Only
one namespace option can be specified.
-N Read the name from this file.
-n Do not enable 'noattr2' mode on V4 filesystems.
-R Replace the attribute. The command will fail if the at-
tribute does not already exist.
-C Create the attribute. The command will fail if the at-
tribute already exists.
-V Read the value from this file.
-v Set the attribute value to a string of this length con-
taining the letter 'v'.
b See the back command.
back Move to the previous location in the position ring.
blockfree
Free block usage information collected by the last execution of
the blockget command. This must be done before another blockget
command can be given, presumably with different arguments than
the previous one.
blockget [-npvs] [-b bno] ... [-i ino] ...
Get block usage. The information is saved for use by a subse-
quent blockuse, ncheck, or blocktrash command.
-b is used to specify filesystem block numbers about which
verbose information should be printed.
-i is used to specify inode numbers about which verbose in-
formation should be printed.
-n is used to save pathnames for inodes visited, this is used
to support the xfs_ncheck(8) command. It also means that
pathnames will be printed for inodes that have problems.
This option uses a lot of memory so is not enabled by de-
fault.
-p causes error messages to be prefixed with the filesystem
name being processed. This is useful if several copies of
xfs_db are run in parallel.
-s restricts output to severe errors only. This is useful if
the output is too long otherwise.
-v enables verbose output. Messages will be printed for every
block and inode processed.
blocktrash [-z] [-o offset] [-n count] [-x min] [-y max] [-s seed]
[-0|1|2|3] [-t type] ...
Trash randomly selected filesystem metadata blocks. Trashing oc-
curs to randomly selected bits in the chosen blocks. This com-
mand is available only in debugging versions of xfs_db. It is
useful for testing xfs_repair(8).
-0 | -1 | -2 | -3
These are used to set the operating mode for blocktrash.
Only one can be used: -0 changed bits are cleared; -1
changed bits are set; -2 changed bits are inverted; -3
changed bits are randomized.
-n supplies the count of block-trashings to perform (default
1).
-o supplies the bit offset at which to start trashing the
block. If the value is preceded by a '+', the trashing
will start at a randomly chosen offset that is larger than
the value supplied. The default is to randomly choose an
offset anywhere in the block.
-s supplies a seed to the random processing.
-t gives a type of blocks to be selected for trashing. Multi-
ple -t options may be given. If no -t options are given
then all metadata types can be trashed.
-x sets the minimum size of bit range to be trashed. The de-
fault value is 1.
-y sets the maximum size of bit range to be trashed. The de-
fault value is 1024.
-z trashes the block at the top of the stack. It is not nec-
essary to run blockget if this option is supplied.
blockuse [-n] [-c count]
Print usage for current filesystem block(s). For each block, the
type and (if any) inode are printed.
-c specifies a count of blocks to process. The default value
is 1 (the current block only).
-n specifies that file names should be printed. The prior
blockget command must have also specified the -n option.
bmap [-a] [-d] [block [len]]
Show the block map for the current inode. The map display can be
restricted to an area of the file with the block and len argu-
ments. If block is given and len is omitted then 1 is assumed for
len.
The -a and -d options are used to select the attribute or data
area of the inode, if neither option is given then both areas are
shown.
bmapinflate [-d dirty_bytes] [-e] [-n nr]
Duplicates the first data fork mapping this many times, as if the
mapping had been repeatedly reflinked. This is an expert-mode
command for exercising high-refcount filesystems only. Existing
data fork mappings will be forgotten and the refcount btree will
not be updated. This command leaves at least the refcount btree
and the inode inconsistent; xfs_repair must be run afterwards.
-d Constrain the memory consumption of new dirty btree blocks
to this quantity. Defaults to 60MiB.
-e Estimate the number of blocks and height of the new data
fork mapping structure and exit without changing anything.
-n Create this many copies of the first mapping.
btdump [-a] [-i]
If the cursor points to a btree node, dump the btree from that
block downward. If instead the cursor points to an inode, dump
the data fork block mapping btree if there is one. If the cursor
points to a directory or extended attribute btree node, dump
that. By default, only records stored in the btree are dumped.
-a If the cursor points at an inode, dump the extended at-
tribute block mapping btree, if present.
-i Dump all keys and pointers in intermediate btree nodes,
and all records in leaf btree nodes.
btheight [-b blksz] [-n recs] [-w max|min|absmax] btree types...
For a given number of btree records and a btree type, report the
number of records and blocks for each level of the btree, and the
total number of blocks. The btree type must be given after the
options.
A raw btree geometry can be provided in the format
"record_bytes:key_bytes:ptr_bytes:header_type", where header_type
is one of "short", "long", "shortcrc", or "longcrc".
The supported btree types are: bnobt, cntbt, inobt, finobt,
bmapbt, refcountbt, and rmapbt. The magic value all can be used
to walk through all btree types.
Options are as follows:
-b is used to override the btree block size. The default is
the filesystem block size.
-n is used to specify the number of records to store. This
argument is required.
-w absmax
shows the maximum possible height for the given btree
types.
-w max
shows only the best case scenario, which is when the btree
blocks are maximally loaded.
-w min
shows only the worst case scenario, which is when the
btree blocks are half full.
convert type number [type number] ... type
Convert from one address form to another. The known types, with
alternate names, are:
agblock or agbno (filesystem block within an allocation group)
agino or aginode (inode number within an allocation group)
agnumber or agno (allocation group number)
bboff or daddroff (byte offset in a daddr)
blkoff or fsboff or agboff (byte offset in a agblock or fs-
block)
byte or fsbyte (byte address in filesystem)
daddr or bb (disk address, 512-byte blocks)
fsblock or fsb or fsbno (filesystem block, see the fsblock
command)
ino or inode (inode number)
inoidx or offset (index of inode in filesystem block)
inooff or inodeoff (byte offset in inode)
Only conversions that "make sense" are allowed. The compound
form (with more than three arguments) is useful for conversions
such as convert agno ag agbno agb fsblock.
crc [-i|-r|-v]
Invalidates, revalidates, or validates the CRC (checksum) field
of the current structure, if it has one. This command is avail-
able only on CRC-enabled filesystems. With no argument, valida-
tion is performed. Each command will display the resulting CRC
value and state.
-i Invalidate the structure's CRC value (incrementing it by
one), and write it to disk.
-r Recalculate the current structure's correct CRC value, and
write it to disk.
-v Validate and display the current value and state of the
structure's CRC.
daddr [-r] [d]
Set current address to the daddr (512 byte block) given by d. If
no value for d is given, the current address is printed, ex-
pressed as a daddr. The type is set to data (uninterpreted).
If an address and the -l option are specified, the current ad-
dress is set to the external log device. If an address and the
-r option are specified, the current address is set to the real-
time device.
dblock filoff
Set current address to the offset filoff (a filesystem block num-
ber) in the data area of the current inode.
debug [flagbits]
Set debug option bits. These are used for debugging xfs_db. If
no value is given for flagbits, print the current debug option
bits. These are for the use of the implementor.
dquot [-g|-p|-u] id
Set current address to a group, project or user quota block for
the given ID. Defaults to user quota.
dump_iunlinked [-a agno ] [-b bucket ] [-q] [-v]
Dump the contents of unlinked buckets.
Options include:
-a Print only this AG's unlinked buckets.
-b Print only this bucket within each AGI.
-q Only print the essentials.
-v Print resource usage of each file on the unlinked lists.
echo [arg] ...
Echo the arguments to the output.
f See the forward command.
forward
Move forward to the next entry in the position ring.
frag [-adflqRrv]
Get file fragmentation data. This prints information about frag-
mentation of file data in the filesystem (as opposed to fragmen-
tation of freespace, for which see the freesp command). Every
file in the filesystem is examined to see how far from ideal its
extent mappings are. A summary is printed giving the totals.
-v sets verbosity, every inode has information printed for
it. The remaining options select which inodes and extents
are examined. If no options are given then all are as-
sumed set, otherwise just those given are enabled.
-a enables processing of attribute data.
-d enables processing of directory data.
-f enables processing of regular file data.
-l enables processing of symbolic link data.
-q enables processing of quota file data.
-R enables processing of realtime control file data.
-r enables processing of realtime file data.
freesp [-bcds] [-A alignment] [-a ag] ... [-e i] [-h h1] ... [-m m]
Summarize free space for the filesystem. The free blocks are ex-
amined and totalled, and displayed in the form of a histogram,
with a count of extents in each range of free extent sizes.
-A reports only free extents with starting blocks aligned to
alignment blocks.
-a adds ag to the list of allocation groups to be processed.
If no -a options are given then all allocation groups are
processed.
-b specifies that the histogram buckets are binary-sized,
with the starting sizes being the powers of 2.
-c specifies that freesp will search the by-size (cnt) space
Btree instead of the default by-block (bno) space Btree.
-d specifies that every free extent will be displayed.
-e specifies that the histogram buckets are equal-sized, with
the size specified as i.
-h specifies a starting block number for a histogram bucket
as h1. Multiple -h's are given to specify the complete
set of buckets.
-m specifies that the histogram starting block numbers are
powers of m. This is the general case of -b.
-s specifies that a final summary of total free extents, free
blocks, and the average free extent size is printed.
fsb See the fsblock command.
fsblock [fsb]
Set current address to the fsblock value given by fsb. If no
value for fsb is given the current address is printed, expressed
as an fsb. The type is set to data (uninterpreted). XFS filesys-
tem block numbers are computed ((agno << agshift) | agblock)
where agshift depends on the size of an allocation group. Use the
convert command to convert to and from this form. Block numbers
given for file blocks (for instance from the bmap command) are in
this form.
fsmap [ start ] [ end ]
Prints the mapping of disk blocks used by an XFS filesystem. The
map lists each extent used by files, allocation group metadata,
journalling logs, and static filesystem metadata, as well as any
regions that are unused. All blocks, offsets, and lengths are
specified in units of 512-byte blocks, no matter what the
filesystem's block size is. The optional start and end arguments
can be used to constrain the output to a particular range of disk
blocks.
fuzz [-c] [-d] field action
Write garbage into a specific structure field on disk. Expert
mode must be enabled to use this command. The operation happens
immediately; there is no buffering.
The fuzz command can take the following actions against a field:
zeroes
Clears all bits in the field.
ones
Sets all bits in the field.
firstbit
Flips the first bit in the field. For a scalar value,
this is the highest bit.
middlebit
Flips the middle bit in the field.
lastbit
Flips the last bit in the field. For a scalar value, this
is the lowest bit.
add Adds a small value to a scalar field.
sub Subtracts a small value from a scalar field.
random
Randomizes the contents of the field.
The following switches affect the write behavior:
-c Skip write verifiers and CRC recalculation; allows invalid
data to be written to disk.
-d Skip write verifiers but perform CRC recalculation; allows
invalid data to be written to disk to test detection of
invalid data.
hash[-d|-pparent_ino]"strings
Prints the hash value of string using the hash function of the
XFS directory and attribute implementation.
If the -d option is specified, the directory-specific hash func-
tion is used. This only makes a difference on filesystems with
ascii case-insensitive lookups enabled.
If the -p option is specified, the parent pointer-specific hash
function is used. The parent directory inumber must be specified
as an argument. This only makes a difference on filesystems with
ascii case-insensitive lookups enabled.
hashcoll [-a] [-s seed] [-n nr] [-p path] -i | names...
Create directory entries or extended attributes names that all
have the same hash value. The metadump name obfuscation algo-
rithm is used here. Names are written to standard output, with a
NULL between each name for use with xargs -0.
-a Create extended attribute names.
-i Read the first name to create from standard input. Up to
255 bytes are read. If this option is not specified,
first names are taken from the command line.
-n nr
Create this many duplicated names. The default is to cre-
ate one name.
-p path
Create directory entries or extended attributes in this
file instead of writing the names to standard output.
-s seed
Seed the random number generator with this value.
help [command]
Print help for one or all commands.
info Displays selected geometry information about the filesystem. The
output will have the same format that mkfs.xfs(8) prints when
creating a filesystem or xfs_info(8) prints when querying a
filesystem.
inode [inode#]
Set the current inode number. If no inode# is given, print the
current inode number.
iunlink [-n nr ]
Allocate inodes and put them on the unlinked list.
Options include:
-n Create this number of unlinked inodes. If not specified,
1 inode will be created.
label [label]
Set the filesystem label. The filesystem label can be used by
mount(8) instead of using a device special file. The maximum
length of an XFS label is 12 characters - use of a longer label
will result in truncation and a warning will be issued. If no la-
bel is given, the current filesystem label is printed.
link [-i ino] [-m] [-p path] [-t ftype] name
In the current directory, create a directory entry with the given
name pointing to a file. The file must be specified either as a
directory tree path as given by the path option; or directly as
an inode number as given by the ino option. The file type in the
directory entry will be determined from the mode of the child
file unless the ftype option is given. The -m option specifies
that the path lookup should be done in the metadata directory
tree. The file being targetted must not be on the iunlink list.
log [stop | start filename]
Start logging output to filename, stop logging, or print the cur-
rent logging status.
logblock [logbno]
Set current address to the log block value given by logbno. If
no value for logbno is given the current address is printed, ex-
pressed as an fsb. The type is set to data (uninterpreted). If
the filesystem has an external log, then the address will be
within the log device. If the filesystem has an internal log,
then the address will be within the internal log.
logformat [-c cycle] [-s sunit]
Reformats the log to the specified log cycle and log stripe unit.
This has the effect of clearing the log destructively. If the
log cycle is not specified, the log is reformatted to the current
cycle. If the log stripe unit is not specified, the stripe unit
from the filesystem superblock is used.
logres Print transaction reservation size information for each transac-
tion type. This makes it easier to find discrepancies in the
reservation calculations between xfsprogs and the kernel, which
will help when diagnosing minimum log size calculation errors.
ls [-im] [paths]...
List the contents of a directory. If a path resolves to a direc-
tory, the directory will be listed. If no paths are supplied and
the IO cursor points at a directory inode, the contents of that
directory will be listed.
The output format is: directory cookie, inode number, file type,
hash, name length, name.
-i Resolve each of the given paths to an inode number and
print that number. If no paths are given and the IO cur-
sor points to an inode, print the inode number.
-m Absolute paths should be walked from the root of the meta-
data directory tree.
metadump [-egow] filename
Dumps metadata to a file. See xfs_metadump(8) for more informa-
tion.
ncheck [-s] [-i ino] ...
Print name-inode pairs. A blockget -n command must be run first
to gather the information.
-i specifies an inode number to be printed. If no -i options
are given then all inodes are printed.
-s specifies that only setuid and setgid files are printed.
p See the print command.
parent [-m] [paths]...
List the parents of a file. If a path resolves to a file, the
parents of that file will be listed. If no paths are supplied
and the IO cursor points at an inode, the parents of that file
will be listed. The -m option causes absolute paths to be walked
from the root of the metadata directory tree.
The output format is: inode number, inode generation, ondisk
namehash, namehash, name length, name.
path [-m] dir_path
Walk the directory tree to an inode using the supplied path. Ab-
solute and relative paths are supported. The -m option causes
absolute paths to be walked from the root of the metadata direc-
tory tree.
pop Pop location from the stack.
print [field-expression] ...
Print field values. If no argument is given, print all fields in
the current structure.
push [command]
Push location to the stack. If command is supplied, set the cur-
rent location to the results of command after pushing the old lo-
cation.
q See the quit command.
quit Exit xfs_db.
rtblock [rtbno]
Set current address to the location on the realtime device given
by rtbno. This value must be a realtime block number. If no
value for rtbno is given the current address is printed, ex-
pressed as an rtbno. The type is set to data (uninterpreted).
rtextent [rtxno]
Set current address to the location on the realtime device given
by rtextent. This value must be a linear address in units of re-
altime extents. If no value for rtextent is given the current
address is printed, expressed as an rtextent. The type is set to
data (uninterpreted).
ring [index]
Show position ring (if no index argument is given), or move to a
specific entry in the position ring given by index.
rtconvert type number [type number] ... type
Convert from one address form to another for realtime section ad-
dresses. The known types, with alternate names, are:
rgblock or rgbno (realtime block within a realtime group)
rgnumber or rgno (realtime group number)
bboff or daddroff (byte offset in a daddr)
blkoff or fsboff or rtboff (byte offset in a rtblock or rtex-
tent)
byte or fsbyte (byte address in filesystem)
daddr or bb (disk address, 512-byte blocks)
rtblock or rtb or rtbno (realtime filesystem block, see the
fsblock command)
rtx or rtextent (realtime extent)
rbmblock or rbmb (realtime bitmap block)
rbmword or rbmw (32-bit word within a realtime bitmap block)
rsumblock or rsmb (realtime summary file block)
rsuminfo or rsmi (32-bit counter within a realtime summary
block)
rsumlog or rsml (log2len parameter used for summary file off-
set computations)
Only conversions that "make sense" are allowed. The compound
form (with more than three arguments) is useful for conversions
such as convert rgno rg rgbno rgb rtblock.
Realtime summary file location conversions have the following
rules: Each info word in the rt summary file counts the number of
free extents of a given log2(length) that start in a given rt
bitmap block.
To compute summary file location information for a given rt
bitmap block, a log2(extent length) must be specified as the last
type/number pair before the conversion type, and the type must be
rsumlog.
For example, these commands tell us where to look in the rt sum-
mary file for the number of free rtextents of length 2^21 start-
ing in rt bitmap block 30:
rtconvert rbmblock 30 rsumlog 21 rsumblock
rtconvert rbmblock 30 rsumlog 21 rsuminfo
To compute the rt bitmap block from summary file location, the
type/number pairs must be specified exactly in the order rsumlog,
rsuminfo, rsumblock.
For example, this command tells us which block in the rt bitmap
file is summarized by info word 809 in rt summary block 10 assum-
ing that the maximum free extent length is 2^21 rtextents:
rtconvert rsumlog 21 rsuminfo 809 rsumblock 10 rbmblock
sb [agno]
Set current address to SB header in allocation group agno. If no
agno is given, use the current allocation group number.
source source-file
Process commands from source-file. source commands can be
nested.
stack View the location stack.
type [type]
Set the current data type to type. If no argument is given, show
the current data type. The possible data types are: agf, agfl,
agi, attr, bmapbta, bmapbtd, bnobt, cntbt, data, dir, dir2,
dqblk, inobt, inode, log, refcntbt, rmapbt, rtbitmap, rtsummary,
sb, symlink and text. See the TYPES section below for more in-
formation on these data types.
timelimit [OPTIONS]
Print the minimum and maximum supported values for inode time-
stamps, quota expiration timers, and quota grace periods sup-
ported by this filesystem. Options include:
--bigtime
Print the time limits of an XFS filesystem with the big-
time feature enabled.
--classic
Print the time limits of a classic XFS filesystem.
--compact
Print all limits as raw values on a single line.
--pretty
Print the timestamps in the current locale's date and time
format instead of raw seconds since the Unix epoch.
unlink name
In the current directory, remove a directory entry with the given
name. The file being targetted will not be put on the iunlink
list.
uuid [uuid | generate | rewrite | restore]
Set the filesystem universally unique identifier (UUID). The
filesystem UUID can be used by mount(8) instead of using a device
special file. The uuid can be set directly to the desired UUID,
or it can be automatically generated using the generate option.
These options will both write the UUID into every copy of the su-
perblock in the filesystem. On a CRC-enabled filesystem, this
will set an incompatible superblock flag, and the filesystem will
not be mountable with older kernels. This can be reverted with
the restore option, which will copy the original UUID back into
place and clear the incompatible flag as needed. rewrite copies
the current UUID from the primary superblock to all secondary
copies of the superblock. If no argument is given, the current
filesystem UUID is printed.
version [feature | versionnum features2]
Enable selected features for a filesystem (certain features can
be enabled on an unmounted filesystem, after mkfs.xfs(8) has cre-
ated the filesystem). Support for unwritten extents can be en-
abled using the extflg option. Support for version 2 log format
can be enabled using the log2 option. Support for extended at-
tributes can be enabled using the attr1 or attr2 option. Once en-
abled, extended attributes cannot be disabled, but the user may
toggle between attr1 and attr2 at will (older kernels may not
support the newer version).
If no argument is given, the current version and feature bits are
printed. With one argument, this command will write the updated
version number into every copy of the superblock in the filesys-
tem. If two arguments are given, they will be used as numeric
values for the versionnum and features2 bits respectively, and
their string equivalent reported (but no modifications are made).
write [-c|-d] [field value] ...
Write a value to disk. Specific fields can be set in structures
(struct mode), or a block can be set to data values (data mode),
or a block can be set to string values (string mode, for symlink
blocks). The operation happens immediately: there is no buffer-
ing.
Struct mode is in effect when the current type is structural,
i.e. not data. For struct mode, the syntax is "write field
value".
Data mode is in effect when the current type is data. In this
case the contents of the block can be shifted or rotated left or
right, or filled with a sequence, a constant value, or a random
value. In this mode write with no arguments gives more informa-
tion on the allowed commands.
-c Skip write verifiers and CRC recalculation; allows invalid
data to be written to disk.
-d Skip write verifiers but perform CRC recalculation. This
allows invalid data to be written to disk to test detec-
tion of invalid data. (This is not possible for some
types.)
TYPES
This section gives the fields in each structure type and their meanings.
Note that some types of block cover multiple actual structures, for in-
stance directory blocks.
agf The AGF block is the header for block allocation information;
it is in the second 512-byte block of each allocation group.
The following fields are defined:
magicnum AGF block magic number, 0x58414746 ('XAGF').
versionnum version number, currently 1.
seqno sequence number starting from 0.
length size in filesystem blocks of the allocation
group. All allocation groups except the last
one of the filesystem have the superblock's
agblocks value here.
bnoroot block number of the root of the Btree holding
free space information sorted by block number.
cntroot block number of the root of the Btree holding
free space information sorted by block count.
bnolevel number of levels in the by-block-number Btree.
cntlevel number of levels in the by-block-count Btree.
flfirst index into the AGFL block of the first active
entry.
fllast index into the AGFL block of the last active
entry.
flcount count of active entries in the AGFL block.
freeblks count of blocks represented in the freespace
Btrees.
longest longest free space represented in the free-
space Btrees.
btreeblks number of blocks held in the AGF Btrees.
agfl The AGFL block contains block numbers for use of the block al-
locator; it is in the fourth 512-byte block of each allocation
group. Each entry in the active list is a block number within
the allocation group that can be used for any purpose if space
runs low. The AGF block fields flfirst, fllast, and flcount
designate which entries are currently active. Entry space is
allocated in a circular manner within the AGFL block. Fields
defined:
bno array of all block numbers. Even those which
are not active are printed.
agi The AGI block is the header for inode allocation information;
it is in the third 512-byte block of each allocation group.
Fields defined:
magicnum AGI block magic number, 0x58414749 ('XAGI').
versionnum version number, currently 1.
seqno sequence number starting from 0.
length size in filesystem blocks of the allocation
group.
count count of inodes allocated.
root block number of the root of the Btree holding
inode allocation information.
level number of levels in the inode allocation
Btree.
freecount count of allocated inodes that are not in use.
newino last inode number allocated.
dirino unused.
unlinked an array of inode numbers within the alloca-
tion group. The entries in the AGI block are
the heads of lists which run through the inode
next_unlinked field. These inodes are to be
unlinked the next time the filesystem is
mounted.
attr An attribute fork is organized as a Btree with the actual data
embedded in the leaf blocks. The root of the Btree is found in
block 0 of the fork. The index (sort order) of the Btree is
the hash value of the attribute name. All the blocks contain
a blkinfo structure at the beginning, see type dir for a de-
scription. Nonleaf blocks are identical in format to those for
version 1 and version 2 directories, see type dir for a de-
scription. Leaf blocks can refer to "local" or "remote" at-
tribute values. Local values are stored directly in the leaf
block. Leaf blocks contain the following fields:
hdr header containing a blkinfo structure info
(magic number 0xfbee), a count of active en-
tries, usedbytes total bytes of names and val-
ues, the firstused byte in the name area,
holes set if the block needs compaction, and
array freemap as for dir leaf blocks.
entries array of structures containing a hashval,
nameidx (index into the block of the name),
and flags incomplete, root, and local.
nvlist array of structures describing the attribute
names and values. Fields always present: val-
uelen (length of value in bytes), namelen, and
name. Fields present for local values: value
(value string). Fields present for remote val-
ues: valueblk (fork block number of containing
the value).
Remote values are stored in an independent block in the at-
tribute fork. Prior to v5, value blocks had no structure, but
in v5 they acquired a header structure with the following
fields:
magic attr3 remote block magic number, 0x5841524d
('XARM').
offset Byte offset of this data block within the
overall attribute value.
bytes Number of bytes stored in this block.
crc Checksum of the attribute block contents.
uuid Filesystem UUID.
owner Inode that owns this attribute value.
bno Block offset of this block within the inode's
attribute fork.
lsn Log serial number of the last time this block
was logged.
data The attribute value data.
bmapbt Files with many extents in their data or attribute fork will
have the extents described by the contents of a Btree for that
fork, instead of being stored directly in the inode. Each
bmap Btree starts with a root block contained within the in-
ode. The other levels of the Btree are stored in filesystem
blocks. The blocks are linked to sibling left and right
blocks at each level, as well as by pointers from parent to
child blocks. Each block contains the following fields:
magic bmap Btree block magic number, 0x424d4150
('BMAP').
level level of this block above the leaf level.
numrecs number of records or keys in the block.
leftsib left (logically lower) sibling block, 0 if
none.
rightsib right (logically higher) sibling block, 0 if
none.
recs [leaf blocks only] array of extent records.
Each record contains startoff, startblock,
blockcount, and extentflag (1 if the extent is
unwritten).
keys [non-leaf blocks only] array of key records.
These are the first key value of each block in
the level below this one. Each record contains
startoff.
ptrs [non-leaf blocks only] array of child block
pointers. Each pointer is a filesystem block
number to the next level in the Btree.
bnobt There is one set of filesystem blocks forming the by-block-
number allocation Btree for each allocation group. The root
block of this Btree is designated by the bnoroot field in the
corresponding AGF block. The blocks are linked to sibling
left and right blocks at each level, as well as by pointers
from parent to child blocks. Each block has the following
fields:
magic BNOBT block magic number, 0x41425442 ('ABTB').
level level number of this block, 0 is a leaf.
numrecs number of data entries in the block.
leftsib left (logically lower) sibling block, 0 if
none.
rightsib right (logically higher) sibling block, 0 if
none.
recs [leaf blocks only] array of freespace records.
Each record contains startblock and block-
count.
keys [non-leaf blocks only] array of key records.
These are the first value of each block in the
level below this one. Each record contains
startblock and blockcount.
ptrs [non-leaf blocks only] array of child block
pointers. Each pointer is a block number
within the allocation group to the next level
in the Btree.
cntbt There is one set of filesystem blocks forming the by-block-
count allocation Btree for each allocation group. The root
block of this Btree is designated by the cntroot field in the
corresponding AGF block. The blocks are linked to sibling left
and right blocks at each level, as well as by pointers from
parent to child blocks. Each block has the following fields:
magic CNTBT block magic number, 0x41425443 ('ABTC').
level level number of this block, 0 is a leaf.
numrecs number of data entries in the block.
leftsib left (logically lower) sibling block, 0 if
none.
rightsib right (logically higher) sibling block, 0 if
none.
recs [leaf blocks only] array of freespace records.
Each record contains startblock and block-
count.
keys [non-leaf blocks only] array of key records.
These are the first value of each block in the
level below this one. Each record contains
blockcount and startblock.
ptrs [non-leaf blocks only] array of child block
pointers. Each pointer is a block number
within the allocation group to the next level
in the Btree.
data User file blocks, and other blocks whose type is unknown, have
this type for display purposes in xfs_db. The block data is
displayed in hexadecimal format.
dir A version 1 directory is organized as a Btree with the direc-
tory data embedded in the leaf blocks. The root of the Btree
is found in block 0 of the file. The index (sort order) of the
Btree is the hash value of the entry name. All the blocks con-
tain a blkinfo structure at the beginning with the following
fields:
forw next sibling block.
back previous sibling block.
magic magic number for this block type.
The non-leaf (node) blocks have the following fields:
hdr header containing a blkinfo structure info
(magic number 0xfebe), the count of active en-
tries, and the level of this block above the
leaves.
btree array of entries containing hashval and before
fields. The before value is a block number
within the directory file to the child block,
the hashval is the last hash value in that
block.
The leaf blocks have the following fields:
hdr header containing a blkinfo structure info
(magic number 0xfeeb), the count of active en-
tries, namebytes (total name string bytes),
holes flag (block needs compaction), and
freemap (array of base, size entries for free
regions).
entries array of structures containing hashval,
nameidx (byte index into the block of the name
string), and namelen.
namelist array of structures containing inumber and
name.
dir2 A version 2 directory has four kinds of blocks. Data blocks
start at offset 0 in the file. There are two kinds of data
blocks: single-block directories have the leaf information em-
bedded at the end of the block, data blocks in multi-block di-
rectories do not. Node and leaf blocks start at offset 32GiB
(with either a single leaf block or the root node block).
Freespace blocks start at offset 64GiB. The node and leaf
blocks form a Btree, with references to the data in the data
blocks. The freespace blocks form an index of longest free
spaces within the data blocks.
A single-block directory block contains the following fields:
bhdr header containing magic number 0x58443242
('XD2B') and an array bestfree of the longest
3 free spaces in the block (offset, length).
bu array of union structures. Each element is ei-
ther an entry or a freespace. For entries,
there are the following fields: inumber, name-
len, name, and tag. For freespace, there are
the following fields: freetag (0xffff),
length, and tag. The tag value is the byte
offset in the block of the start of the entry
it is contained in.
bleaf array of leaf entries containing hashval and
address. The address is a 64-bit word offset
into the file.
btail tail structure containing the total count of
leaf entries and stale count of unused leaf
entries.
A data block contains the following fields:
dhdr header containing magic number 0x58443244
('XD2D') and an array bestfree of the longest
3 free spaces in the block (offset, length).
du array of union structures as for bu.
Leaf blocks have two possible forms. If the Btree consists of
a single leaf then the freespace information is in the leaf
block, otherwise it is in separate blocks and the root of the
Btree is a node block. A leaf block contains the following
fields:
lhdr header containing a blkinfo structure info
(magic number 0xd2f1 for the single leaf case,
0xd2ff for the true Btree case), the total
count of leaf entries, and stale count of un-
used leaf entries.
lents leaf entries, as for bleaf.
lbests [single leaf only] array of values which rep-
resent the longest freespace in each data
block in the directory.
ltail [single leaf only] tail structure containing
bestcount count of lbests.
A node block is identical to that for types attr and dir.
A freespace block contains the following fields:
fhdr header containing magic number 0x58443246
('XD2F'), firstdb first data block number cov-
ered by this freespace block, nvalid number of
valid entries, and nused number of entries
representing real data blocks.
fbests array of values as for lbests.
dqblk The quota information is stored in files referred to by the
superblock uquotino and pquotino fields. Each filesystem block
in a quota file contains a constant number of quota entries.
The quota entry size is currently 136 bytes, so with a 4KiB
filesystem block size there are 30 quota entries per block.
The dquot command is used to locate these entries in the
filesystem. The file entries are indexed by the user or
project identifier to determine the block and offset. Each
quota entry has the following fields:
magic magic number, 0x4451 ('DQ').
version version number, currently 1.
flags flags, values include 0x01 for user quota,
0x02 for project quota.
id user or project identifier.
blk_hardlimit absolute limit on blocks in use.
blk_softlimit preferred limit on blocks in use.
ino_hardlimit absolute limit on inodes in use.
ino_softlimit preferred limit on inodes in use.
bcount blocks actually in use.
icount inodes actually in use.
itimer time when service will be refused if soft
limit is violated for inodes.
btimer time when service will be refused if soft
limit is violated for blocks.
iwarns number of warnings issued about inode limit
violations.
bwarns number of warnings issued about block limit
violations.
rtb_hardlimit absolute limit on realtime blocks in use.
rtb_softlimit preferred limit on realtime blocks in use.
rtbcount realtime blocks actually in use.
rtbtimer time when service will be refused if soft
limit is violated for realtime blocks.
rtbwarns number of warnings issued about realtime
block limit violations.
inobt There is one set of filesystem blocks forming the inode allo-
cation Btree for each allocation group. The root block of this
Btree is designated by the root field in the corresponding AGI
block. The blocks are linked to sibling left and right blocks
at each level, as well as by pointers from parent to child
blocks. Each block has the following fields:
magic INOBT block magic number, 0x49414254 ('IABT').
level level number of this block, 0 is a leaf.
numrecs number of data entries in the block.
leftsib left (logically lower) sibling block, 0 if
none.
rightsib right (logically higher) sibling block, 0 if
none.
recs [leaf blocks only] array of inode records.
Each record contains startino allocation-group
relative inode number, freecount count of free
inodes in this chunk, and free bitmap, LSB
corresponds to inode 0.
keys [non-leaf blocks only] array of key records.
These are the first value of each block in the
level below this one. Each record contains
startino.
ptrs [non-leaf blocks only] array of child block
pointers. Each pointer is a block number
within the allocation group to the next level
in the Btree.
inode Inodes are allocated in "chunks" of 64 inodes each. Usually a
chunk is multiple filesystem blocks, although there are cases
with large filesystem blocks where a chunk is less than one
block. The inode Btree (see inobt above) refers to the inode
numbers per allocation group. The inode numbers directly re-
flect the location of the inode block on disk. Use the inode
command to point xfs_db to a specific inode. Each inode con-
tains four regions: core, next_unlinked, u, and a. core con-
tains the fixed information. next_unlinked is separated from
the core due to journaling considerations, see type agi field
unlinked. u is a union structure that is different in size
and format depending on the type and representation of the
file data ("data fork"). a is an optional union structure to
describe attribute data, that is different in size, format,
and location depending on the presence and representation of
attribute data, and the size of the u data ("attribute fork").
xfs_db automatically selects the proper union members based on
information in the inode.
The following are fields in the inode core:
magic inode magic number, 0x494e ('IN').
mode mode and type of file, as described in
chmod(2), mknod(2), and stat(2).
version inode version, 1 or 2.
format format of u union data (0: xfs_dev_t, 1: local
file - in-inode directory or symlink, 2: ex-
tent list, 3: Btree root, 4: unique id [un-
used]).
nlinkv1 number of links to the file in a version 1 in-
ode.
nlinkv2 number of links to the file in a version 2 in-
ode.
projid_lo owner's project id (low word; version 2 inode
only). projid_hi owner's project id (high
word; version 2 inode only).
uid owner's user id.
gid owner's group id.
atime time last accessed (seconds and nanoseconds).
mtime time last modified.
ctime time created or inode last modified.
size number of bytes in the file.
nblocks total number of blocks in the file including
indirect and attribute.
extsize basic/minimum extent size for the file.
nextents number of extents in the data fork.
naextents number of extents in the attribute fork.
forkoff attribute fork offset in the inode, in 64-bit
words from the start of u.
aformat format of a data (1: local attribute data, 2:
extent list, 3: Btree root).
dmevmask DMAPI event mask.
dmstate DMAPI state information.
newrtbm file is the realtime bitmap and is "new" for-
mat.
prealloc file has preallocated data space after EOF.
realtime file data is in the realtime subvolume.
gen inode generation number.
The following fields are in the u data fork union:
bmbt bmap Btree root. This looks like a bmapbtd
block with redundant information removed.
bmx array of extent descriptors.
dev dev_t for the block or character device.
sfdir shortform (in-inode) version 1 directory. This
consists of a hdr containing the parent inode
number and a count of active entries in the
directory, followed by an array list of
hdr.count entries. Each such entry contains
inumber, namelen, and name string.
sfdir2 shortform (in-inode) version 2 directory. This
consists of a hdr containing a count of active
entries in the directory, an i8count of en-
tries with inumbers that don't fit in a 32-bit
value, and the parent inode number, followed
by an array list of hdr.count entries. Each
such entry contains namelen, a saved offset
used when the directory is converted to a
larger form, a name string, and the inumber.
symlink symbolic link string value.
The following fields are in the a attribute fork union if it
exists:
bmbt bmap Btree root, as above.
bmx array of extent descriptors.
sfattr shortform (in-inode) attribute values. This
consists of a hdr containing a totsize (total
size in bytes) and a count of active entries,
followed by an array list of hdr.count en-
tries. Each such entry contains namelen, val-
uelen, root flag, name, and value.
log Log blocks contain the journal entries for XFS. It's not use-
ful to examine these with xfs_db, use xfs_logprint(8) instead.
refcntbt There is one set of filesystem blocks forming the reference
count Btree for each allocation group. The root block of this
Btree is designated by the refcntroot field in the correspond-
ing AGF block. The blocks are linked to sibling left and
right blocks at each level, as well as by pointers from parent
to child blocks. Each block has the following fields:
magic REFC block magic number, 0x52334643 ('R3FC').
level level number of this block, 0 is a leaf.
numrecs number of data entries in the block.
leftsib left (logically lower) sibling block, 0 if
none.
rightsib right (logically higher) sibling block, 0 if
none.
recs [leaf blocks only] array of reference count
records. Each record contains startblock,
blockcount, and refcount.
keys [non-leaf blocks only] array of key records.
These are the first value of each block in the
level below this one. Each record contains
startblock.
ptrs [non-leaf blocks only] array of child block
pointers. Each pointer is a block number
within the allocation group to the next level
in the Btree.
rmapbt There is one set of filesystem blocks forming the reverse map-
ping Btree for each allocation group. The root block of this
Btree is designated by the rmaproot field in the corresponding
AGF block. The blocks are linked to sibling left and right
blocks at each level, as well as by pointers from parent to
child blocks. Each block has the following fields:
magic RMAP block magic number, 0x524d4233 ('RMB3').
level level number of this block, 0 is a leaf.
numrecs number of data entries in the block.
leftsib left (logically lower) sibling block, 0 if
none.
rightsib right (logically higher) sibling block, 0 if
none.
recs [leaf blocks only] array of reference count
records. Each record contains startblock,
blockcount, owner, offset, attr_fork,
bmbt_block, and unwritten.
keys [non-leaf blocks only] array of double-key
records. The first ("low") key contains the
first value of each block in the level below
this one. The second ("high") key contains the
largest key that can be used to identify any
record in the subtree. Each record contains
startblock, owner, offset, attr_fork, and
bmbt_block.
ptrs [non-leaf blocks only] array of child block
pointers. Each pointer is a block number
within the allocation group to the next level
in the Btree.
rtbitmap If the filesystem has a realtime subvolume, then the rbmino
field in the superblock refers to a file that contains the re-
altime bitmap. Each bit in the bitmap file controls the allo-
cation of a single realtime extent (set == free). The bitmap
is processed in 32-bit words, the LSB of a word is used for
the first extent controlled by that bitmap word. The atime
field of the realtime bitmap inode contains a counter that is
used to control where the next new realtime file will start.
rtsummary If the filesystem has a realtime subvolume, then the rsumino
field in the superblock refers to a file that contains the re-
altime summary data. The summary file contains a two-dimen-
sional array of 16-bit values. Each value counts the number
of free extent runs (consecutive free realtime extents) of a
given range of sizes that starts in a given bitmap block. The
size ranges are binary buckets (low size in the bucket is a
power of 2). There are as many size ranges as are necessary
given the size of the realtime subvolume. The first dimension
is the size range, the second dimension is the starting bitmap
block number (adjacent entries are for the same size, adjacent
bitmap blocks).
sb There is one sb (superblock) structure per allocation group.
It is the first disk block in the allocation group. Only the
first one (block 0 of the filesystem) is actually used; the
other blocks are redundant information for xfs_repair(8) to
use if the first superblock is damaged. Fields defined:
magicnum superblock magic number, 0x58465342 ('XFSB').
blocksize filesystem block size in bytes.
dblocks number of filesystem blocks present in the
data subvolume.
rblocks number of filesystem blocks present in the re-
altime subvolume.
rextents number of realtime extents that rblocks con-
tain.
uuid unique identifier of the filesystem.
logstart starting filesystem block number of the log
(journal). If this value is 0 the log is "ex-
ternal".
rootino root inode number.
rbmino realtime bitmap inode number.
rsumino realtime summary data inode number.
rextsize realtime extent size in filesystem blocks.
agblocks size of an allocation group in filesystem
blocks.
agcount number of allocation groups.
rbmblocks number of realtime bitmap blocks.
logblocks number of log blocks (filesystem blocks).
versionnum filesystem version information. This value is
currently 1, 2, 3, or 4 in the low 4 bits. If
the low bits are 4 then the other bits have
additional meanings. 1 is the original value.
2 means that attributes were used. 3 means
that version 2 inodes (large link counts) were
used. 4 is the bitmask version of the version
number. In this case, the other bits are used
as flags (0x0010: attributes were used,
0x0020: version 2 inodes were used, 0x0040:
quotas were used, 0x0080: inode cluster align-
ment is in force, 0x0100: data stripe align-
ment is in force, 0x0200: the shared_vn field
is used, 0x1000: unwritten extent tracking is
on, 0x2000: version 2 directories are in use).
sectsize sector size in bytes, currently always 512.
This is the size of the superblock and the
other header blocks.
inodesize inode size in bytes.
inopblock number of inodes per filesystem block.
fname obsolete, filesystem name.
fpack obsolete, filesystem pack name.
blocklog log2 of blocksize.
sectlog log2 of sectsize.
inodelog log2 of inodesize.
inopblog log2 of inopblock.
agblklog log2 of agblocks (rounded up).
rextslog log2 of rextents.
inprogress mkfs.xfs(8) or xfs_copy(8) aborted before com-
pleting this filesystem.
imax_pct maximum percentage of filesystem space used
for inode blocks.
icount number of allocated inodes.
ifree number of allocated inodes that are not in
use.
fdblocks number of free data blocks.
frextents number of free realtime extents.
uquotino user quota inode number.
pquotino project quota inode number; this is currently
unused.
qflags quota status flags (0x01: user quota account-
ing is on, 0x02: user quota limits are en-
forced, 0x04: quotacheck has been run on user
quotas, 0x08: project quota accounting is on,
0x10: project quota limits are enforced, 0x20:
quotacheck has been run on project quotas).
flags random flags. 0x01: only read-only mounts are
allowed.
shared_vn shared version number (shared readonly
filesystems).
inoalignmt inode chunk alignment in filesystem blocks.
unit stripe or RAID unit.
width stripe or RAID width.
dirblklog log2 of directory block size (filesystem
blocks).
symlink Symbolic link blocks are used only when the symbolic link
value does not fit inside the inode. The block content is just
the string value. Bytes past the logical end of the symbolic
link value have arbitrary values.
text User file blocks, and other blocks whose type is unknown, have
this type for display purposes in xfs_db. The block data is
displayed in two columns: Hexadecimal format and printable
ASCII chars.
DIAGNOSTICS
Many messages can come from the blockget command. If the filesystem is
completely corrupt, a core dump might be produced instead of the message
device is not a valid filesystem
If the filesystem is very large (has many files) then blockget might run
out of memory. In this case the message
out of memory
is printed.
The following is a description of the most likely problems and the asso-
ciated messages. Most of the diagnostics produced are only meaningful
with an understanding of the structure of the filesystem.
agf_freeblks n, counted m in ag a
The freeblocks count in the allocation group header for alloca-
tion group a doesn't match the number of blocks counted free.
agf_longest n, counted m in ag a
The longest free extent in the allocation group header for allo-
cation group a doesn't match the longest free extent found in the
allocation group.
agi_count n, counted m in ag a
The allocated inode count in the allocation group header for al-
location group a doesn't match the number of inodes counted in
the allocation group.
agi_freecount n, counted m in ag a
The free inode count in the allocation group header for alloca-
tion group a doesn't match the number of inodes counted free in
the allocation group.
block a/b expected inum 0 got i
The block number is specified as a pair (allocation group number,
block in the allocation group). The block is used multiple times
(shared), between multiple inodes. This message usually follows
a message of the next type.
block a/b expected type unknown got y
The block is used multiple times (shared).
block a/b type unknown not expected
SEE ALSO
mkfs.xfs(8), xfs_admin(8), xfs_copy(8), xfs_logprint(8), xfs_metad-
ump(8), xfs_ncheck(8), xfs_repair(8), mount(8), chmod(2), mknod(2),
stat(2), xfs(5).
xfs_db(8)
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