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authorIan Kent <raven@themaw.net>2005-07-27 11:43:45 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2005-07-27 16:25:51 -0700
commit104e49fc1e1656142869fab0e75d7df52b72eed9 (patch)
tree4ba88793943da0fda56bbc98b404ea862ba89af6 /fs/autofs4
parent0f94c8e1256fcb786e1918e30bdaeccf669bf63c (diff)
[PATCH] autofs4: fix infamous "Busy inodes after umount ..." message
If the automount daemon receives a signal which causes it to sumarily terminate the autofs4 module leaks dentries. The same problem exists with detached mount requests without the warning. This patch cleans these dentries at umount. Signed-off-by: Ian Kent <raven@themaw.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'fs/autofs4')
-rw-r--r--fs/autofs4/autofs_i.h1
-rw-r--r--fs/autofs4/inode.c73
2 files changed, 74 insertions, 0 deletions
diff --git a/fs/autofs4/autofs_i.h b/fs/autofs4/autofs_i.h
index 9c09641ce90..fca83e28edc 100644
--- a/fs/autofs4/autofs_i.h
+++ b/fs/autofs4/autofs_i.h
@@ -92,6 +92,7 @@ struct autofs_wait_queue {
struct autofs_sb_info {
u32 magic;
+ struct dentry *root;
struct file *pipe;
pid_t oz_pgrp;
int catatonic;
diff --git a/fs/autofs4/inode.c b/fs/autofs4/inode.c
index 4bb14cc6804..0a3c05d1016 100644
--- a/fs/autofs4/inode.c
+++ b/fs/autofs4/inode.c
@@ -16,6 +16,7 @@
#include <linux/pagemap.h>
#include <linux/parser.h>
#include <linux/bitops.h>
+#include <linux/smp_lock.h>
#include "autofs_i.h"
#include <linux/module.h>
@@ -76,6 +77,66 @@ void autofs4_free_ino(struct autofs_info *ino)
kfree(ino);
}
+/*
+ * Deal with the infamous "Busy inodes after umount ..." message.
+ *
+ * Clean up the dentry tree. This happens with autofs if the user
+ * space program goes away due to a SIGKILL, SIGSEGV etc.
+ */
+static void autofs4_force_release(struct autofs_sb_info *sbi)
+{
+ struct dentry *this_parent = sbi->root;
+ struct list_head *next;
+
+ spin_lock(&dcache_lock);
+repeat:
+ next = this_parent->d_subdirs.next;
+resume:
+ while (next != &this_parent->d_subdirs) {
+ struct dentry *dentry = list_entry(next, struct dentry, d_child);
+
+ /* Negative dentry - don`t care */
+ if (!simple_positive(dentry)) {
+ next = next->next;
+ continue;
+ }
+
+ if (!list_empty(&dentry->d_subdirs)) {
+ this_parent = dentry;
+ goto repeat;
+ }
+
+ next = next->next;
+ spin_unlock(&dcache_lock);
+
+ DPRINTK("dentry %p %.*s",
+ dentry, (int)dentry->d_name.len, dentry->d_name.name);
+
+ dput(dentry);
+ spin_lock(&dcache_lock);
+ }
+
+ if (this_parent != sbi->root) {
+ struct dentry *dentry = this_parent;
+
+ next = this_parent->d_child.next;
+ this_parent = this_parent->d_parent;
+ spin_unlock(&dcache_lock);
+ DPRINTK("parent dentry %p %.*s",
+ dentry, (int)dentry->d_name.len, dentry->d_name.name);
+ dput(dentry);
+ spin_lock(&dcache_lock);
+ goto resume;
+ }
+ spin_unlock(&dcache_lock);
+
+ dput(sbi->root);
+ sbi->root = NULL;
+ shrink_dcache_sb(sbi->sb);
+
+ return;
+}
+
static void autofs4_put_super(struct super_block *sb)
{
struct autofs_sb_info *sbi = autofs4_sbi(sb);
@@ -85,6 +146,10 @@ static void autofs4_put_super(struct super_block *sb)
if ( !sbi->catatonic )
autofs4_catatonic_mode(sbi); /* Free wait queues, close pipe */
+ /* Clean up and release dangling references */
+ if (sbi)
+ autofs4_force_release(sbi);
+
kfree(sbi);
DPRINTK("shutting down");
@@ -199,6 +264,7 @@ int autofs4_fill_super(struct super_block *s, void *data, int silent)
s->s_fs_info = sbi;
sbi->magic = AUTOFS_SBI_MAGIC;
+ sbi->root = NULL;
sbi->catatonic = 0;
sbi->exp_timeout = 0;
sbi->oz_pgrp = process_group(current);
@@ -267,6 +333,13 @@ int autofs4_fill_super(struct super_block *s, void *data, int silent)
sbi->pipe = pipe;
/*
+ * Take a reference to the root dentry so we get a chance to
+ * clean up the dentry tree on umount.
+ * See autofs4_force_release.
+ */
+ sbi->root = dget(root);
+
+ /*
* Success! Install the root dentry now to indicate completion.
*/
s->s_root = root;