[PATCH] autofs4: fix false negative return from expire
Fix the case where an expire returns busy on a tree mount when it is in fact
not busy. This case was overlooked when the patch to prevent the expiring
away of "scaffolding" directories for tree mounts was applied.
The problem arises when a tree of mounts is a member of a map with other keys.
The current logic will not expire the tree if any other mount in the map is
busy. The solution is to maintain a "minimum" use count for each autofs
dentry and compare this to the actual dentry usage count during expire.
Signed-off-by: Ian Kent <raven@themaw.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/fs/autofs4/root.c b/fs/autofs4/root.c
index c7ff357..d196712 100644
--- a/fs/autofs4/root.c
+++ b/fs/autofs4/root.c
@@ -490,6 +490,7 @@
{
struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
struct autofs_info *ino = autofs4_dentry_ino(dentry);
+ struct autofs_info *p_ino;
struct inode *inode;
char *cp;
@@ -523,6 +524,10 @@
dentry->d_fsdata = ino;
ino->dentry = dget(dentry);
+ atomic_inc(&ino->count);
+ p_ino = autofs4_dentry_ino(dentry->d_parent);
+ if (p_ino && dentry->d_parent != dentry)
+ atomic_inc(&p_ino->count);
ino->inode = inode;
dir->i_mtime = CURRENT_TIME;
@@ -549,11 +554,17 @@
{
struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
struct autofs_info *ino = autofs4_dentry_ino(dentry);
+ struct autofs_info *p_ino;
/* This allows root to remove symlinks */
if ( !autofs4_oz_mode(sbi) && !capable(CAP_SYS_ADMIN) )
return -EACCES;
+ if (atomic_dec_and_test(&ino->count)) {
+ p_ino = autofs4_dentry_ino(dentry->d_parent);
+ if (p_ino && dentry->d_parent != dentry)
+ atomic_dec(&p_ino->count);
+ }
dput(ino->dentry);
dentry->d_inode->i_size = 0;
@@ -570,6 +581,7 @@
{
struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
struct autofs_info *ino = autofs4_dentry_ino(dentry);
+ struct autofs_info *p_ino;
if (!autofs4_oz_mode(sbi))
return -EACCES;
@@ -584,8 +596,12 @@
spin_unlock(&dentry->d_lock);
spin_unlock(&dcache_lock);
+ if (atomic_dec_and_test(&ino->count)) {
+ p_ino = autofs4_dentry_ino(dentry->d_parent);
+ if (p_ino && dentry->d_parent != dentry)
+ atomic_dec(&p_ino->count);
+ }
dput(ino->dentry);
-
dentry->d_inode->i_size = 0;
dentry->d_inode->i_nlink = 0;
@@ -599,6 +615,7 @@
{
struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
struct autofs_info *ino = autofs4_dentry_ino(dentry);
+ struct autofs_info *p_ino;
struct inode *inode;
if ( !autofs4_oz_mode(sbi) )
@@ -621,6 +638,10 @@
dentry->d_fsdata = ino;
ino->dentry = dget(dentry);
+ atomic_inc(&ino->count);
+ p_ino = autofs4_dentry_ino(dentry->d_parent);
+ if (p_ino && dentry->d_parent != dentry)
+ atomic_inc(&p_ino->count);
ino->inode = inode;
dir->i_nlink++;
dir->i_mtime = CURRENT_TIME;