[3.13.y-ckt stable] Patch "mnt: Improve the umount_tree flags" has been added to staging queue
Kamal Mostafa
kamal at canonical.com
Tue May 26 23:33:54 UTC 2015
This is a note to let you know that I have just added a patch titled
mnt: Improve the umount_tree flags
to the linux-3.13.y-queue branch of the 3.13.y-ckt extended stable tree
which can be found at:
http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.13.y-queue
This patch is scheduled to be released in version 3.13.11-ckt21.
If you, or anyone else, feels it should not be added to this tree, please
reply to this email.
For more information about the 3.13.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable
Thanks.
-Kamal
------
>From 04887931d7584a24cf533995fd6f3aa7d66c353d Mon Sep 17 00:00:00 2001
From: "Eric W. Biederman" <ebiederm at xmission.com>
Date: Wed, 24 Dec 2014 07:20:01 -0600
Subject: mnt: Improve the umount_tree flags
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 at xmission.com>
[ luis: backported to 3.16:
- dropped change to __detach_mounts() ]
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
fs/namespace.c | 29 +++++++++++++++--------------
fs/pnode.h | 1 -
2 files changed, 15 insertions(+), 15 deletions(-)
diff --git a/fs/namespace.c b/fs/namespace.c
index 289c216..01296f9 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -1240,14 +1240,15 @@ 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;
@@ -1261,7 +1262,7 @@ void umount_tree(struct mount *mnt, int how)
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) {
@@ -1269,7 +1270,7 @@ void umount_tree(struct mount *mnt, int how)
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)) {
put_mountpoint(p->mnt_mp);
@@ -1371,14 +1372,14 @@ static int do_umount(struct mount *mnt, int flags)
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;
}
}
@@ -1538,7 +1539,7 @@ struct mount *copy_tree(struct mount *mnt, struct dentry *dentry,
out:
if (res) {
lock_mount_hash();
- umount_tree(res, 0);
+ umount_tree(res, UMOUNT_SYNC);
unlock_mount_hash();
}
return q;
@@ -1562,7 +1563,7 @@ void drop_collected_mounts(struct vfsmount *mnt)
{
namespace_lock();
lock_mount_hash();
- umount_tree(real_mount(mnt), 0);
+ umount_tree(real_mount(mnt), UMOUNT_SYNC);
unlock_mount_hash();
namespace_unlock();
}
@@ -1718,7 +1719,7 @@ static int attach_recursive_mnt(struct mount *source_mnt,
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);
@@ -1893,7 +1894,7 @@ static int do_loopback(struct path *path, const char *old_name,
err = graft_tree(mnt, parent, mp);
if (err) {
lock_mount_hash();
- umount_tree(mnt, 0);
+ umount_tree(mnt, UMOUNT_SYNC);
unlock_mount_hash();
}
out2:
@@ -2264,7 +2265,7 @@ void mark_mounts_for_expiry(struct list_head *mounts)
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();
@@ -2335,7 +2336,7 @@ static void shrink_submounts(struct mount *mnt)
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);
}
}
}
diff --git a/fs/pnode.h b/fs/pnode.h
index 4a24635..16afc3d 100644
--- a/fs/pnode.h
+++ b/fs/pnode.h
@@ -47,7 +47,6 @@ int get_dominating_id(struct mount *mnt, const struct path *root);
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);
--
1.9.1
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