I'l give this a try but I do not quite get the point, so I may be way off:
One of your assumptions needs a tuneup. How inodes (one the objects you want to learn about) are stored is implementation dependent, so ffs filesystems may have a different structure from ufs filesystems.
There is no one single fits-everything kind of answer.
What you have to do is to get the source code for the filesystem(s) you want, then look in the .h files for structures. Look for inode, and vnode. This stuff will be in driver source for a particular filesystem flavor.
You can get a lot of this information and write simple C programs using
which is a wrapper to calls that show directory entries, one of the places you need to look. Structures on the disk are a whole lot tougher to navigate through. And directories have file structure on top of the file metadata.
Now my turn:
Why are you going this way? Please tell us what you want to accomplish. Not how you think you can do it.
Answers like
' I need to see the actual list of segments for a file and their absolute offsets'
are what we need.
This User Gave Thanks to jim mcnamara For This Post:
The purpose of those comands are to find the newest file in a directory acvrdind to system date, and it has to be recursively found in each directory.
The problem is that i want to list in a long format every found file, but the commands i use produce unexpected results ,so the output lists in a... (5 Replies)
Hi ,
I have a typical situation. I have 4 files and with different headers (number of headers is varible ).
I need to make such a merged file which will have headers combined from all files (comman coluns should appear once only).
For example -
File 1
H1|H2|H3|H4
11|12|13|14
21|22|23|23... (1 Reply)
I have to find the specific formatted file is present in the received list in the directory, for which I have written:
file_list=`ls -lrt /tmp/vinay/act/files |grep "$cdate"| awk '{print $9}'`
while read fileStr
do
find $file_list $fileStr > /dev/null
status=`echo $?`
if ; then
... (3 Replies)
Hi All,
We are copying all the files into ARCHIVE directory after we process them. We are doing this process from last 2 years, now we have a lot of files in ARCHIVE directory.
Now I need to find when the first file is copied into this directory?
If I Issue,
ls -l /ARCHIVE/*.* | tail -1... (3 Replies)
I have an issue with a korn shell script that I am writing. The script parses through a configuration file which lists a heap of path/directories for some files which need to be FTP'd. Now the script needs to check whether there are any files which have not been processed and are X minutes old.
... (2 Replies)
Hi ,
I have a .txt file in which I have multiple headers, the header record starts with $ symbol...like the first column name is $Account.
I have to keep the header in the first line and delete all the remaining headers which are in the file.
I tried using sort adc.txt | uniq -u , but my... (7 Replies)
Hi I need to merge 4 files. The issue i am facing is all the files have headers and i do not want them in the final output file. Can anybody suggest how to do it? (5 Replies)
Hi All,
In the file names we have dates.
Based on the file format given by the user,
if any file is not existed for a particular date with in a given interval we should consider that file is missing.
I have the below files in the directory /bin/daily/voda_files.
... (9 Replies)
Discussion started by: nalu
9 Replies
LEARN ABOUT DEBIAN
xfs
xfs(5) File Formats Manual xfs(5)NAME
xfs - layout of the XFS filesystem
DESCRIPTION
An XFS filesystem can reside on a regular disk partition or on a logical volume. An XFS filesystem has up to three parts: a data section,
a log section, and a realtime section. Using the default mkfs.xfs(8) options, the realtime section is absent, and the log area is con-
tained within the data section. The log section can be either separate from the data section or contained within it. The filesystem sec-
tions are divided into a certain number of blocks, whose size is specified at mkfs.xfs(8) time with the -b option.
The data section contains all the filesystem metadata (inodes, directories, indirect blocks) as well as the user file data for ordinary
(non-realtime) files and the log area if the log is internal to the data section. The data section is divided into a number of allocation
groups. The number and size of the allocation groups are chosen by mkfs.xfs(8) so that there is normally a small number of equal-sized
groups. The number of allocation groups controls the amount of parallelism available in file and block allocation. It should be increased
from the default if there is sufficient memory and a lot of allocation activity. The number of allocation groups should not be set very
high, since this can cause large amounts of CPU time to be used by the filesystem, especially when the filesystem is nearly full. More
allocation groups are added (of the original size) when xfs_growfs(8) is run.
The log section (or area, if it is internal to the data section) is used to store changes to filesystem metadata while the filesystem is
running until those changes are made to the data section. It is written sequentially during normal operation and read only during mount.
When mounting a filesystem after a crash, the log is read to complete operations that were in progress at the time of the crash.
The realtime section is used to store the data of realtime files. These files had an attribute bit set through xfsctl(3) after file cre-
ation, before any data was written to the file. The realtime section is divided into a number of extents of fixed size (specified at
mkfs.xfs(8) time). Each file in the realtime section has an extent size that is a multiple of the realtime section extent size.
Each allocation group contains several data structures. The first sector contains the superblock. For allocation groups after the first,
the superblock is just a copy and is not updated after mkfs.xfs(8). The next three sectors contain information for block and inode alloca-
tion within the allocation group. Also contained within each allocation group are data structures to locate free blocks and inodes; these
are located through the header structures.
Each XFS filesystem is labeled with a Universal Unique Identifier (UUID). The UUID is stored in every allocation group header and is used
to help distinguish one XFS filesystem from another, therefore you should avoid using dd(1) or other block-by-block copying programs to
copy XFS filesystems. If two XFS filesystems on the same machine have the same UUID, xfsdump(8) may become confused when doing incremental
and resumed dumps. xfsdump(8) and xfsrestore(8) are recommended for making copies of XFS filesystems.
OPERATIONS
Some functionality specific to the XFS filesystem is accessible to applications through the xfsctl(3) and by-handle (see open_by_handle(3))
interfaces.
MOUNT OPTIONS
Refer to the mount(8) manual entry for descriptions of the individual XFS mount options.
SEE ALSO xfsctl(3), mount(8), mkfs.xfs(8), xfs_info(8), xfs_admin(8), xfsdump(8), xfsrestore(8).
xfs(5)