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Message-Id: <20150502190123.653551148@linuxfoundation.org>
Date: Sat, 2 May 2015 21:01:55 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-kernel@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
stable@...r.kernel.org, "Eric W. Biederman" <ebiederm@...ssion.com>
Subject: [PATCH 3.19 093/177] mnt: Improve the umount_tree flags
3.19-stable review patch. If anyone has any objections, please let me know.
------------------
From: "Eric W. Biederman" <ebiederm@...ssion.com>
commit e819f152104c9f7c9fe50e1aecce6f5d4bf06d65 upstream.
- Remove the unneeded declaration from pnode.h
- Mark umount_tree static as it has no callers outside of namespace.c
- Define an enumeration of umount_tree's flags.
- Pass umount_tree's flags in by name
This removes the magic numbers 0, 1 and 2 making the code a little
clearer and makes it possible for there to be lazy unmounts that don't
propagate. Which is what __detach_mounts actually wants for example.
Signed-off-by: "Eric W. Biederman" <ebiederm@...ssion.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
fs/namespace.c | 31 ++++++++++++++++---------------
fs/pnode.h | 1 -
2 files changed, 16 insertions(+), 16 deletions(-)
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -1323,14 +1323,15 @@ static inline void namespace_lock(void)
down_write(&namespace_sem);
}
+enum umount_tree_flags {
+ UMOUNT_SYNC = 1,
+ UMOUNT_PROPAGATE = 2,
+};
/*
* mount_lock must be held
* namespace_sem must be held for write
- * how = 0 => just this tree, don't propagate
- * how = 1 => propagate; we know that nobody else has reference to any victims
- * how = 2 => lazy umount
*/
-void umount_tree(struct mount *mnt, int how)
+static void umount_tree(struct mount *mnt, enum umount_tree_flags how)
{
HLIST_HEAD(tmp_list);
struct mount *p;
@@ -1344,7 +1345,7 @@ void umount_tree(struct mount *mnt, int
hlist_for_each_entry(p, &tmp_list, mnt_hash)
list_del_init(&p->mnt_child);
- if (how)
+ if (how & UMOUNT_PROPAGATE)
propagate_umount(&tmp_list);
hlist_for_each_entry(p, &tmp_list, mnt_hash) {
@@ -1352,7 +1353,7 @@ void umount_tree(struct mount *mnt, int
list_del_init(&p->mnt_list);
__touch_mnt_namespace(p->mnt_ns);
p->mnt_ns = NULL;
- if (how < 2)
+ if (how & UMOUNT_SYNC)
p->mnt.mnt_flags |= MNT_SYNC_UMOUNT;
if (mnt_has_parent(p)) {
hlist_del_init(&p->mnt_mp_list);
@@ -1457,14 +1458,14 @@ static int do_umount(struct mount *mnt,
if (flags & MNT_DETACH) {
if (!list_empty(&mnt->mnt_list))
- umount_tree(mnt, 2);
+ umount_tree(mnt, UMOUNT_PROPAGATE);
retval = 0;
} else {
shrink_submounts(mnt);
retval = -EBUSY;
if (!propagate_mount_busy(mnt, 2)) {
if (!list_empty(&mnt->mnt_list))
- umount_tree(mnt, 1);
+ umount_tree(mnt, UMOUNT_PROPAGATE|UMOUNT_SYNC);
retval = 0;
}
}
@@ -1496,7 +1497,7 @@ void __detach_mounts(struct dentry *dent
lock_mount_hash();
while (!hlist_empty(&mp->m_list)) {
mnt = hlist_entry(mp->m_list.first, struct mount, mnt_mp_list);
- umount_tree(mnt, 2);
+ umount_tree(mnt, UMOUNT_PROPAGATE);
}
unlock_mount_hash();
put_mountpoint(mp);
@@ -1658,7 +1659,7 @@ struct mount *copy_tree(struct mount *mn
out:
if (res) {
lock_mount_hash();
- umount_tree(res, 0);
+ umount_tree(res, UMOUNT_SYNC);
unlock_mount_hash();
}
return q;
@@ -1682,7 +1683,7 @@ void drop_collected_mounts(struct vfsmou
{
namespace_lock();
lock_mount_hash();
- umount_tree(real_mount(mnt), 0);
+ umount_tree(real_mount(mnt), UMOUNT_SYNC);
unlock_mount_hash();
namespace_unlock();
}
@@ -1865,7 +1866,7 @@ static int attach_recursive_mnt(struct m
out_cleanup_ids:
while (!hlist_empty(&tree_list)) {
child = hlist_entry(tree_list.first, struct mount, mnt_hash);
- umount_tree(child, 0);
+ umount_tree(child, UMOUNT_SYNC);
}
unlock_mount_hash();
cleanup_group_ids(source_mnt, NULL);
@@ -2045,7 +2046,7 @@ static int do_loopback(struct path *path
err = graft_tree(mnt, parent, mp);
if (err) {
lock_mount_hash();
- umount_tree(mnt, 0);
+ umount_tree(mnt, UMOUNT_SYNC);
unlock_mount_hash();
}
out2:
@@ -2416,7 +2417,7 @@ void mark_mounts_for_expiry(struct list_
while (!list_empty(&graveyard)) {
mnt = list_first_entry(&graveyard, struct mount, mnt_expire);
touch_mnt_namespace(mnt->mnt_ns);
- umount_tree(mnt, 1);
+ umount_tree(mnt, UMOUNT_PROPAGATE|UMOUNT_SYNC);
}
unlock_mount_hash();
namespace_unlock();
@@ -2487,7 +2488,7 @@ static void shrink_submounts(struct moun
m = list_first_entry(&graveyard, struct mount,
mnt_expire);
touch_mnt_namespace(m->mnt_ns);
- umount_tree(m, 1);
+ umount_tree(m, UMOUNT_PROPAGATE|UMOUNT_SYNC);
}
}
}
--- a/fs/pnode.h
+++ b/fs/pnode.h
@@ -47,7 +47,6 @@ int get_dominating_id(struct mount *mnt,
unsigned int mnt_get_count(struct mount *mnt);
void mnt_set_mountpoint(struct mount *, struct mountpoint *,
struct mount *);
-void umount_tree(struct mount *, int);
struct mount *copy_tree(struct mount *, struct dentry *, int);
bool is_path_reachable(struct mount *, struct dentry *,
const struct path *root);
--
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