The patch titled
Subject: autofs: use path_is_mountpoint() to fix unreliable d_mountpoint() checks
has been added to the -mm tree. Its filename is
autofs-use-path_is_mountpoint-to-fix-unreliable-d_mountpoint-checks.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/autofs-use-path_is_mountpoint-to-fix-unreliable-d_mountpoint-checks.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/autofs-use-path_is_mountpoint-to-fix-unreliable-d_mountpoint-checks.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Ian Kent <ikent@xxxxxxxxxx>
Subject: autofs: use path_is_mountpoint() to fix unreliable d_mountpoint() checks
If an automount mount is clone(2)ed into a file system that is propagation
private, when it later expires in the originating namespace, subsequent
calls to autofs ->d_automount() for that dentry in the original namespace
will return ELOOP until the mount is umounted in the cloned namespace.
Now that a struct path is available where needed use path_is_mountpoint()
instead of d_mountpoint() so we don't get false positives when checking if
a dentry is a mount point in the current namespace.
Link: http://lkml.kernel.org/r/20161011053418.27645.15241.stgit@xxxxxxxxxxxxxxxx
Signed-off-by: Ian Kent <raven@xxxxxxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Eric W. Biederman <ebiederm@xxxxxxxxxxxx>
Cc: Omar Sandoval <osandov@xxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/autofs4/root.c | 24 ++++++++++++++++--------
1 file changed, 16 insertions(+), 8 deletions(-)
diff -puN fs/autofs4/root.c~autofs-use-path_is_mountpoint-to-fix-unreliable-d_mountpoint-checks fs/autofs4/root.c
--- a/fs/autofs4/root.c~autofs-use-path_is_mountpoint-to-fix-unreliable-d_mountpoint-checks
+++ a/fs/autofs4/root.c
@@ -107,12 +107,15 @@ static int autofs4_dir_open(struct inode
{
struct dentry *dentry = file->f_path.dentry;
struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
+ struct path path;
pr_debug("file=%p dentry=%p %pd\n", file, dentry, dentry);
if (autofs4_oz_mode(sbi))
goto out;
+ path = file->f_path;
+
/*
* An empty directory in an autofs file system is always a
* mount point. The daemon must have failed to mount this
@@ -123,7 +126,7 @@ static int autofs4_dir_open(struct inode
* it.
*/
spin_lock(&sbi->lookup_lock);
- if (!d_mountpoint(dentry) && simple_empty(dentry)) {
+ if (!path_is_mountpoint(&path) && simple_empty(dentry)) {
spin_unlock(&sbi->lookup_lock);
return -ENOENT;
}
@@ -372,15 +375,15 @@ static struct vfsmount *autofs4_d_automo
/*
* If the dentry is a symlink it's equivalent to a directory
- * having d_mountpoint() true, so there's no need to call back
- * to the daemon.
+ * having path_is_mountpoint() true, so there's no need to call
+ * back to the daemon.
*/
if (d_really_is_positive(dentry) && d_is_symlink(dentry)) {
spin_unlock(&sbi->fs_lock);
goto done;
}
- if (!d_mountpoint(dentry)) {
+ if (!path_is_mountpoint(path)) {
/*
* It's possible that user space hasn't removed directories
* after umounting a rootless multi-mount, although it
@@ -434,8 +437,13 @@ static int autofs4_d_manage(struct path
/* The daemon never waits. */
if (autofs4_oz_mode(sbi)) {
- if (!d_mountpoint(dentry))
- return -EISDIR;
+ if (rcu_walk) {
+ if (!path_is_mountpoint_rcu(path))
+ return -EISDIR;
+ } else {
+ if (!path_is_mountpoint(path))
+ return -EISDIR;
+ }
return 0;
}
@@ -463,7 +471,7 @@ static int autofs4_d_manage(struct path
if (ino->flags & AUTOFS_INF_WANT_EXPIRE)
return 0;
- if (d_mountpoint(dentry))
+ if (path_is_mountpoint_rcu(path))
return 0;
inode = d_inode_rcu(dentry);
if (inode && S_ISLNK(inode->i_mode))
@@ -490,7 +498,7 @@ static int autofs4_d_manage(struct path
* we can avoid needless calls ->d_automount() and avoid
* an incorrect ELOOP error return.
*/
- if ((!d_mountpoint(dentry) && !simple_empty(dentry)) ||
+ if ((!path_is_mountpoint(path) && !simple_empty(dentry)) ||
(d_really_is_positive(dentry) && d_is_symlink(dentry)))
status = -EISDIR;
}
_
Patches currently in -mm which might be from ikent@xxxxxxxxxx are
vfs-change-d_manage-to-take-a-struct-path.patch
vfs-add-path_is_mountpoint-helper.patch
vfs-add-path_has_submounts.patch
autofs-change-autofs4_expire_wait-to-take-struct-path.patch
autofs-change-autofs4_wait-to-take-struct-path.patch
autofs-use-path_is_mountpoint-to-fix-unreliable-d_mountpoint-checks.patch
autofs-use-path_has_submounts-to-fix-unreliable-have_submount-checks.patch
vfs-remove-unused-have_submounts-function.patch
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