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diff --git a/doc/debugging/gfid-to-path.md b/doc/debugging/gfid-to-path.md new file mode 100644 index 00000000000..1917bf2cca1 --- /dev/null +++ b/doc/debugging/gfid-to-path.md @@ -0,0 +1,68 @@ +# 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/<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/<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="(<DISTRIBUTE:test-dht> <POSIX(/mnt/brick-test/b):vm1:/mnt/brick-test/b/dir//file3>)" +``` + +--- +#### References and links: +[posix: placeholders for GFID to path conversion](http://review.gluster.org/5951) |
