[RFC] client: don't use special inode for /..

Commit Message

Jeff Layton Aug. 10, 2016, 4:30 p.m. UTC

The CEPH_INO_DOTDOT thing is quite strange. Under most OS (Linux
included), the parent of the root is itself. IOW, at the root, '.' and
'..' refer to the same inode.

Change the ceph client to do the same, as this allows users to get
valid stat info for '..', as well as elimnating some special-casing.

Signed-off-by: Jeff Layton <[e-mail]>
---
 src/client/Client.cc  | 13 +++----------
 src/include/ceph_fs.h |  1 -
 2 files changed, 3 insertions(+), 11 deletions(-)

Comments

Patrick Donnelly Aug. 10, 2016, 8:08 p.m. UTC | #1

On Wed, Aug 10, 2016 at 12:30 PM, Jeff Layton <[e-mail]> wrote:
> The CEPH_INO_DOTDOT thing is quite strange. Under most OS (Linux
> included), the parent of the root is itself. IOW, at the root, '.' and
> '..' refer to the same inode.
>
> Change the ceph client to do the same, as this allows users to get
> valid stat info for '..', as well as elimnating some special-casing.
>
> Signed-off-by: Jeff Layton <[e-mail]>

Don't forget Client::_lookup:

  if (dname == "..") {
    if (dir->dn_set.empty())
      r = -ENOENT;
    else
      *target = dir->get_first_parent()->dir->parent_inode; //dirs
can't be hard-linked
    goto done;
  }

Otherwise LGTM.

Patch

diff --git a/src/client/Client.cc b/src/client/Client.cc
index 2df632fc0e08..77f464ad76ae 100644
--- a/src/client/Client.cc
+++ b/src/client/Client.cc
@@ -7244,9 +7244,9 @@  int Client::readdir_r_cb(dir_result_t *d, add_dirent_cb_t cb, void *p)
       fill_stat(in, &st);
       fill_dirent(&de, "..", S_IFDIR, st.st_ino, next_off);
     } else {
-      /* must be at the root (no parent),
-       * so we add the dotdot with a special inode (3) */
-      fill_dirent(&de, "..", S_IFDIR, CEPH_INO_DOTDOT, next_off);
+      /* must be at the root (no parent), so fill out with same info as "." */
+      fill_stat(diri, &st);
+      fill_dirent(&de, "..", S_IFDIR, st.st_ino, next_off);
     }
 
 
@@ -9684,13 +9684,6 @@  int Client::ll_getattr(Inode *in, struct stat *attr, int uid, int gid)
   tout(cct) << "ll_getattr" << std::endl;
   tout(cct) << vino.ino.val << std::endl;
 
-  /* special case for dotdot (..) */
-  if (vino.ino.val == CEPH_INO_DOTDOT) {
-    attr->st_mode = S_IFDIR | 0755;
-    attr->st_nlink = 2;
-    return 0;
-  }
-
   int res;
   if (vino.snapid < CEPH_NOSNAP)
     res = 0;
diff --git a/src/include/ceph_fs.h b/src/include/ceph_fs.h
index 772e475ccc91..1610aaf17cc2 100644
--- a/src/include/ceph_fs.h
+++ b/src/include/ceph_fs.h
@@ -28,7 +28,6 @@ 
 
 #define CEPH_INO_ROOT   1
 #define CEPH_INO_CEPH   2       /* hidden .ceph dir */
-#define CEPH_INO_DOTDOT 3	/* used by ceph fuse for parent (..) */
 #define CEPH_INO_LOST_AND_FOUND 4	/* reserved ino for use in recovery */
 
 /* arbitrary limit on max # of monitors (cluster of 3 is typical) */