The patch titled
Subject: autofs: use path_has_submounts() to fix unreliable have_submount() checks
has been added to the -mm tree. Its filename is
autofs-use-path_has_submounts-to-fix-unreliable-have_submount-checks.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/autofs-use-path_has_submounts-to-fix-unreliable-have_submount-checks.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/autofs-use-path_has_submounts-to-fix-unreliable-have_submount-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_has_submounts() to fix unreliable have_submount() 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_has_submounts()
instead of have_submounts() so we don't get false positives when checking
if a dentry is a mount point or contains mounts in the current namespace.
Link: http://lkml.kernel.org/r/20161011053423.27645.91233.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/dev-ioctl.c | 2 +-
fs/autofs4/root.c | 14 +++++++-------
fs/autofs4/waitq.c | 10 +++++++---
3 files changed, 15 insertions(+), 11 deletions(-)
diff -puN fs/autofs4/dev-ioctl.c~autofs-use-path_has_submounts-to-fix-unreliable-have_submount-checks fs/autofs4/dev-ioctl.c
--- a/fs/autofs4/dev-ioctl.c~autofs-use-path_has_submounts-to-fix-unreliable-have_submount-checks
+++ a/fs/autofs4/dev-ioctl.c
@@ -575,7 +575,7 @@ static int autofs_dev_ioctl_ismountpoint
devid = new_encode_dev(dev);
- err = have_submounts(path.dentry);
+ err = path_has_submounts(&path);
if (follow_down_one(&path))
magic = path.dentry->d_sb->s_magic;
diff -puN fs/autofs4/root.c~autofs-use-path_has_submounts-to-fix-unreliable-have_submount-checks fs/autofs4/root.c
--- a/fs/autofs4/root.c~autofs-use-path_has_submounts-to-fix-unreliable-have_submount-checks
+++ a/fs/autofs4/root.c
@@ -387,16 +387,16 @@ static struct vfsmount *autofs4_d_automo
/*
* It's possible that user space hasn't removed directories
* after umounting a rootless multi-mount, although it
- * should. For v5 have_submounts() is sufficient to handle
- * this because the leaves of the directory tree under the
- * mount never trigger mounts themselves (they have an autofs
- * trigger mount mounted on them). But v4 pseudo direct mounts
- * do need the leaves to trigger mounts. In this case we
- * have no choice but to use the list_empty() check and
+ * should. For v5 path_has_submounts() is sufficient to
+ * handle this because the leaves of the directory tree under
+ * the mount never trigger mounts themselves (they have an
+ * autofs trigger mount mounted on them). But v4 pseudo direct
+ * mounts do need the leaves to trigger mounts. In this case
+ * we have no choice but to use the list_empty() check and
* require user space behave.
*/
if (sbi->version > 4) {
- if (have_submounts(dentry)) {
+ if (path_has_submounts(path)) {
spin_unlock(&sbi->fs_lock);
goto done;
}
diff -puN fs/autofs4/waitq.c~autofs-use-path_has_submounts-to-fix-unreliable-have_submount-checks fs/autofs4/waitq.c
--- a/fs/autofs4/waitq.c~autofs-use-path_has_submounts-to-fix-unreliable-have_submount-checks
+++ a/fs/autofs4/waitq.c
@@ -250,8 +250,9 @@ autofs4_find_wait(struct autofs_sb_info
static int validate_request(struct autofs_wait_queue **wait,
struct autofs_sb_info *sbi,
const struct qstr *qstr,
- struct dentry *dentry, enum autofs_notify notify)
+ struct path *path, enum autofs_notify notify)
{
+ struct dentry *dentry = path->dentry;
struct autofs_wait_queue *wq;
struct autofs_info *ino;
@@ -314,6 +315,7 @@ static int validate_request(struct autof
*/
if (notify == NFY_MOUNT) {
struct dentry *new = NULL;
+ struct path this;
int valid = 1;
/*
@@ -333,7 +335,9 @@ static int validate_request(struct autof
dentry = new;
}
}
- if (have_submounts(dentry))
+ this.mnt = path->mnt;
+ this.dentry = dentry;
+ if (path_has_submounts(&this))
valid = 0;
if (new)
@@ -406,7 +410,7 @@ int autofs4_wait(struct autofs_sb_info *
return -EINTR;
}
- ret = validate_request(&wq, sbi, &qstr, dentry, notify);
+ ret = validate_request(&wq, sbi, &qstr, path, notify);
if (ret <= 0) {
if (ret != -EINTR)
mutex_unlock(&sbi->wq_mutex);
_
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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