git: sbin/hammer: Allow pfs commands directly handle pfs

[Tomohiro Kusumi]

commit a42b6da657e45b10986036aef9ed7b737b4909ee
Author: Tomohiro Kusumi <kusumi.tomohiro at gmail.com>
Date:   Sat Apr 11 05:32:18 2015 +0900

    sbin/hammer: Allow pfs commands directly handle pfs
    
    - pfs commands can handle a link to pfs, but not the pfs itself.
      This commit allows pfs commands to directly handle pfs node,
      in addition to doing it via link. Being able to execute them
      only via link is strange behavior and should be able to do via
      both ways.
    
    - This commit basically makes both link and non-link path go through
      scanpfsid() which scans pfs id and returns fd of its parent dir.
      In the existing code only link path goes through pfs id scan code,
      so pfs commands are unable to directly handle non-link pfs node
      itself (even if one wants to do so).
    
      ==========
      example1 - using existing /sbin/hammer
    
      # ls -l ./test1
      lrwxr-xr-x  1 root  wheel  10 Apr  8 05:52 ./test1 -> @@-1:00001
      # hammer pfs-downgrade @@-1:00001
      pfs-downgrade of PFS#1 () failed: Directory not empty
      # hammer pfs-destroy ./@@-1:00001
      You have requested that PFS#1 () be destroyed
      <snip>
      Destroying PFS #1 () in  5 4 3 2 1.. starting destruction pass
      pfs-destroy of PFS#1 failed: Directory not empty
    
      ==========
      example2 - using this commit to directly destroy pfs
    
      # hammer pfs-destroy ./@@-1:00001
      You have requested that PFS#1 () be destroyed
      <snip>
      Destroying PFS #1 () in  5 4 3 2 1.. starting destruction pass
      pfs-destroy of PFS#1 succeeded!
      # hammer pfs-status ./test1
      Cannot access PFS ./test1: No such file or directory
    
      The only case that breaks current behavior is when there is a
      regular directory whose format matches (not existing) pfs name,
      although this is not likely to happen in the real world. This
      is inevitable since stat(2) also recognizes pfs as a directory
      (also see hammer_mkroot_pseudofs()).
    
      # mkdir ./@@-1:00005
      # hammer pfs-status ./@@-1:00005
      Cannot access PFS ./@@-1:00005: No such file or directory
    
      ==========
      example3 - another example using this commit.
    
      Actually location of the pfs link doesn't matter as the pfs node
      represents the root inode of pfs, but not a subdirectory of where
      the pfs link is made in the root filesystem. This is confusing
      though when there are more than 1 HAMMER filesystems in a single
      system as "@@-1:00001" could indicate different pfs-es depending
      on where/how commands are executed. Having access to pfs-es via
      symlinks (created by pfs-master|slave) is usually a clearer way.
    
      # mkdir -p a/b/c/d/e
      # cd a/b/c/d/e
      # hammer pfs-master test2 > /dev/null
      # ls -l ./test2
      lrwxr-xr-x  1 root  wheel  10 Apr 10 04:12 ./test2 -> @@-1:00001
      # cd ../../../../..
      # hammer pfs-destroy @@-1:00001
      You have requested that PFS#1 () be destroyed
      <snip>
      Destroying PFS #1 () in  5 4 3 2 1.. starting destruction pass
      pfs-destroy of PFS#1 succeeded!
    
      # hammer pfs-slave test3 > /dev/null
      # ls -l ./test3
      lrwxr-xr-x  1 root  wheel  10 Apr 12 16:30 ./test3 -> @@0x0000000000000001:00001
      # hammer pfs-destroy a/b/c/d/e/@@0x0000000000000001:00001
      You have requested that PFS#1 () be destroyed
      <snip>
      Destroying PFS #1 () in  5 4 3 2 1.. starting destruction pass
      pfs-destroy of PFS#1 succeeded!

Summary of changes:
 sbin/hammer/cmd_pseudofs.c | 142 +++++++++++++++++++++++++++------------------
 1 file changed, 86 insertions(+), 56 deletions(-)

http://gitweb.dragonflybsd.org/dragonfly.git/commitdiff/a42b6da657e45b10986036aef9ed7b737b4909ee


-- 
DragonFly BSD source repository