From 98583a509f1c4ab3cdc20df668e11774fa65085b Mon Sep 17 00:00:00 2001 From: Prashanth Pai Date: Wed, 27 Aug 2014 15:02:49 +0530 Subject: doc: Converting GFID to Path. This is an attempt to document various possible ways to externally get file/dir path from its GFID. Change-Id: Ic31725a9706ddae8972aea9bb58f3b70978dbd06 Signed-off-by: Prashanth Pai Reviewed-on: http://review.gluster.org/8552 Reviewed-by: Humble Devassy Chirammal Tested-by: Gluster Build System Reviewed-by: Vijay Bellur --- doc/debugging/gfid-to-path.md | 73 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 73 insertions(+) create mode 100644 doc/debugging/gfid-to-path.md (limited to 'doc') diff --git a/doc/debugging/gfid-to-path.md b/doc/debugging/gfid-to-path.md new file mode 100644 index 00000000000..09c459e52c8 --- /dev/null +++ b/doc/debugging/gfid-to-path.md @@ -0,0 +1,73 @@ +#Convert GFID to Path + +GlusterFS internal file identifier (GFID) is a uuid that is unique to each +file across the entire cluster. This is analogous to inode number in a +normal filesystem. The GFID of a file is stored in its xattr named +`trusted.gfid`. + +####Special mount using [gfid-access translator][1]: +~~~ +mount -t glusterfs -o aux-gfid-mount vm1:test /mnt/testvol +~~~ + +Assuming, you have `GFID` of a file from changelog (or somewhere else). +For trying this out, you can get `GFID` of a file from mountpoint: +~~~ +getfattr -n glusterfs.gfid.string /mnt/testvol/dir/file +~~~ + + +--- +###Get file path from GFID (Method 1): +**(Lists hardlinks delimited by `:`, returns path as seen from mountpoint)** + +####Turn on build-pgfid option +~~~ +gluster volume set test build-pgfid on +~~~ +Read virtual xattr `glusterfs.ancestry.path` which contains the file path +~~~ +getfattr -n glusterfs.ancestry.path -e text /mnt/testvol/.gfid/ +~~~ + +**Example:** +~~~ +[root@vm1 glusterfs]# ls -il /mnt/testvol/dir/ +total 1 +10610563327990022372 -rw-r--r--. 2 root root 3 Jul 17 18:05 file +10610563327990022372 -rw-r--r--. 2 root root 3 Jul 17 18:05 file3 + +[root@vm1 glusterfs]# getfattr -n glusterfs.gfid.string /mnt/testvol/dir/file +getfattr: Removing leading '/' from absolute path names +# file: mnt/testvol/dir/file +glusterfs.gfid.string="11118443-1894-4273-9340-4b212fa1c0e4" + +[root@vm1 glusterfs]# getfattr -n glusterfs.ancestry.path -e text /mnt/testvol/.gfid/11118443-1894-4273-9340-4b212fa1c0e4 +getfattr: Removing leading '/' from absolute path names +# file: mnt/testvol/.gfid/11118443-1894-4273-9340-4b212fa1c0e4 +glusterfs.ancestry.path="/dir/file:/dir/file3" +~~~ + +--- +###Get file path from GFID (Method 2): +**(Does not list all hardlinks, returns backend brick path)** +~~~ +getfattr -n trusted.glusterfs.pathinfo -e text /mnt/testvol/.gfid/ +~~~ + +**Example:** +~~~ +[root@vm1 glusterfs]# getfattr -n trusted.glusterfs.pathinfo -e text /mnt/testvol/.gfid/11118443-1894-4273-9340-4b212fa1c0e4 +getfattr: Removing leading '/' from absolute path names +# file: mnt/testvol/.gfid/11118443-1894-4273-9340-4b212fa1c0e4 +trusted.glusterfs.pathinfo="( )" +~~~ + +--- +###Get file path from GFID (Method 3): +https://gist.github.com/semiosis/4392640 + +--- +####References and links: +[posix: placeholders for GFID to path conversion](http://review.gluster.org/5951) +[1]: https://github.com/gluster/glusterfs/blob/master/doc/features/gfid-access.md -- cgit