From: Erez Zadok <[EMAIL PROTECTED]>

The old logic was broken in one place, which another place tried to "fix"
incorrectly.  Also added detailed comments to explain the new/correct logic.

Signed-off-by: Erez Zadok <[EMAIL PROTECTED]>
Signed-off-by: Josef 'Jeff' Sipek <[EMAIL PROTECTED]>
---
 fs/unionfs/commonfops.c |   17 ++++++++++++-----
 fs/unionfs/dentry.c     |   18 +++++++++++++-----
 2 files changed, 25 insertions(+), 10 deletions(-)

diff --git a/fs/unionfs/commonfops.c b/fs/unionfs/commonfops.c
index 69d9c87..83001aa 100644
--- a/fs/unionfs/commonfops.c
+++ b/fs/unionfs/commonfops.c
@@ -135,14 +135,21 @@ static void cleanup_file(struct file *file)
                                       "file %p\n", file);
                        else {
                                unionfs_read_lock(sb);
+                               /* decrement count of open files */
                                branchput(sb, i);
                                unionfs_read_unlock(sb);
-                               /* XXX: is it OK to use sb->s_root here? */
-                               unionfs_mntput(sb->s_root, i);
-                               /* mntget b/c fput below will call mntput */
-                               unionfs_mntget(sb->s_root, bindex);
+                               /*
+                                * fput will perform an mntput for us on the
+                                * correct branch.  Although we're using the
+                                * file's old branch configuration, bindex,
+                                * which is the old index, correctly points
+                                * to the right branch in the file's branch
+                                * list.  In other words, we're going to
+                                * mntput the correct branch even if
+                                * branches have been added/removed.
+                                */
+                               fput(unionfs_lower_file_idx(file, bindex));
                        }
-                       fput(unionfs_lower_file_idx(file, bindex));
                }
        }
 
diff --git a/fs/unionfs/dentry.c b/fs/unionfs/dentry.c
index 95cea3b..db0ef43 100644
--- a/fs/unionfs/dentry.c
+++ b/fs/unionfs/dentry.c
@@ -258,14 +258,22 @@ out_this:
        /* finally, lock this dentry and revalidate it */
        verify_locked(dentry);
        dgen = atomic_read(&UNIONFS_D(dentry)->generation);
-       saved_bstart = dbstart(dentry);
-       saved_bend = dbend(dentry);
        valid = __unionfs_d_revalidate_one(dentry, nd);
 
-       if (valid && chain_len > 0 && sbgen != dgen) {
-               for (bindex = saved_bstart; bindex <= saved_bend; bindex++)
+       /*
+        * If __unionfs_d_revalidate_one() succeeded above, then it will
+        * have incremented the refcnt of the mnt's, but also the branch
+        * indices of the dentry will have been updated (to take into
+        * account any branch insertions/deletion.  So the current
+        * dbstart/dbend match the current, and new, indices of the mnts
+        * which __unionfs_d_revalidate_one has incremented.  Note: the "if"
+        * test below does not depend on whether chain_len was 0 or greater.
+        */
+       if (valid && sbgen != dgen)
+               for (bindex = dbstart(dentry);
+                    bindex <= dbend(dentry);
+                    bindex++)
                        unionfs_mntput(dentry, bindex);
-       }
 
 out_free:
        /* unlock/dput all dentries in chain and return status */
-- 
1.5.2.rc1.165.gaf9b

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