The patch titled
vfs: mountinfo stable peer group id
has been removed from the -mm tree. Its filename was
vfs-mountinfo-stable-peer-group-id.patch
This patch was dropped because an updated version will be merged
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: vfs: mountinfo stable peer group id
From: Miklos Szeredi <mszeredi@xxxxxxx>
Add a stable identifier for shared mounts.
Signed-off-by: Miklos Szeredi <mszeredi@xxxxxxx>
Cc: Ram Pai <linuxram@xxxxxxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Dave Hansen <haveblue@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
Documentation/filesystems/proc.txt | 12 +----
fs/namespace.c | 7 ++-
fs/pnode.c | 63 ++++++++++++++++++---------
fs/pnode.h | 1
include/linux/mount.h | 1
5 files changed, 52 insertions(+), 32 deletions(-)
diff -puN Documentation/filesystems/proc.txt~vfs-mountinfo-stable-peer-group-id Documentation/filesystems/proc.txt
--- a/Documentation/filesystems/proc.txt~vfs-mountinfo-stable-peer-group-id
+++ a/Documentation/filesystems/proc.txt
@@ -2367,18 +2367,12 @@ MNTOPTS: per mount options
SBOPTS: per super block options
PROPAGATION: propagation type
-propagation type: <propagation_flag>[:<mntid>][,...]
- note: 'shared' flag is followed by the mntid of its peer mount
- 'slave' flag is followed by the mntid of its master mount
+propagation type: <propagation_flag>[:<peergrpid>][,...]
+ note: 'shared' flag is followed by the id of this mount's peer group
+ 'slave' flag is followed by the peer group id of its master mount
'private' flag stands by itself
'unbindable' flag stands by itself
-The 'mntid' used in the propagation type is a canonical ID of the peer
-group (currently the smallest ID within the group is used for this
-purpose, but this should not be relied on). Since mounts can be added
-or removed from the peer group, this ID only guaranteed to stay the
-same on a static propagation tree.
-
For more information see:
Documentation/filesystems/sharedsubtree.txt
diff -puN fs/namespace.c~vfs-mountinfo-stable-peer-group-id fs/namespace.c
--- a/fs/namespace.c~vfs-mountinfo-stable-peer-group-id
+++ a/fs/namespace.c
@@ -95,6 +95,7 @@ struct vfsmount *alloc_vfsmnt(const char
return NULL;
}
+ mnt->mnt_pgid = -1;
atomic_set(&mnt->mnt_count, 1);
INIT_LIST_HEAD(&mnt->mnt_hash);
INIT_LIST_HEAD(&mnt->mnt_child);
@@ -545,8 +546,10 @@ static struct vfsmount *clone_mnt(struct
mnt->mnt_master = old;
clear_mnt_shared(mnt);
} else if (!(flag & CL_PRIVATE)) {
- if ((flag & CL_PROPAGATION) || IS_MNT_SHARED(old))
- list_add(&mnt->mnt_share, &old->mnt_share);
+ if (flag & CL_PROPAGATION)
+ set_mnt_shared(old);
+ if (IS_MNT_SHARED(old))
+ make_mnt_peer(old, mnt);
if (IS_MNT_SLAVE(old))
list_add(&mnt->mnt_slave, &old->mnt_slave);
mnt->mnt_master = old->mnt_master;
diff -puN fs/pnode.c~vfs-mountinfo-stable-peer-group-id fs/pnode.c
--- a/fs/pnode.c~vfs-mountinfo-stable-peer-group-id
+++ a/fs/pnode.c
@@ -8,10 +8,14 @@
*/
#include <linux/mnt_namespace.h>
#include <linux/mount.h>
+#include <linux/idr.h>
#include <linux/fs.h>
#include "internal.h"
#include "pnode.h"
+static DEFINE_SPINLOCK(mnt_pgid_lock);
+static DEFINE_IDA(mnt_pgid_ida);
+
/* return the next shared peer mount of @p */
static inline struct vfsmount *next_peer(struct vfsmount *p)
{
@@ -28,47 +32,58 @@ static inline struct vfsmount *next_slav
return list_entry(p->mnt_slave.next, struct vfsmount, mnt_slave);
}
-void set_mnt_shared(struct vfsmount *mnt)
+static void __set_mnt_shared(struct vfsmount *mnt)
{
mnt->mnt_flags &= ~MNT_PNODE_MASK;
mnt->mnt_flags |= MNT_SHARED;
}
-void clear_mnt_shared(struct vfsmount *mnt)
+void set_mnt_shared(struct vfsmount *mnt)
{
- mnt->mnt_flags &= ~MNT_SHARED;
+ int res;
+
+ retry:
+ spin_lock(&mnt_pgid_lock);
+ if (IS_MNT_SHARED(mnt)) {
+ spin_unlock(&mnt_pgid_lock);
+ return;
+ }
+
+ res = ida_get_new(&mnt_pgid_ida, &mnt->mnt_pgid);
+ spin_unlock(&mnt_pgid_lock);
+ if (res == -EAGAIN) {
+ if (ida_pre_get(&mnt_pgid_ida, GFP_KERNEL))
+ goto retry;
+ }
+ __set_mnt_shared(mnt);
}
-static int __peer_group_id(struct vfsmount *mnt)
+void clear_mnt_shared(struct vfsmount *mnt)
{
- struct vfsmount *m;
- int id = mnt->mnt_id;
-
- for (m = next_peer(mnt); m != mnt; m = next_peer(m))
- id = min(id, m->mnt_id);
+ if (IS_MNT_SHARED(mnt)) {
+ mnt->mnt_flags &= ~MNT_SHARED;
+ mnt->mnt_pgid = -1;
+ }
+}
- return id;
+void make_mnt_peer(struct vfsmount *old, struct vfsmount *mnt)
+{
+ mnt->mnt_pgid = old->mnt_pgid;
+ list_add(&mnt->mnt_share, &old->mnt_share);
+ __set_mnt_shared(mnt);
}
-/* return the smallest ID within the peer group */
int get_peer_group_id(struct vfsmount *mnt)
{
- int id;
-
- spin_lock(&vfsmount_lock);
- id = __peer_group_id(mnt);
- spin_unlock(&vfsmount_lock);
-
- return id;
+ return mnt->mnt_pgid;
}
-/* return the smallest ID within the master's peer group */
int get_master_id(struct vfsmount *mnt)
{
int id;
spin_lock(&vfsmount_lock);
- id = __peer_group_id(mnt->mnt_master);
+ id = get_peer_group_id(mnt->mnt_master);
spin_unlock(&vfsmount_lock);
return id;
@@ -92,7 +107,13 @@ static int do_make_slave(struct vfsmount
if (peer_mnt == mnt)
peer_mnt = NULL;
}
- list_del_init(&mnt->mnt_share);
+ if (!list_empty(&mnt->mnt_share))
+ list_del_init(&mnt->mnt_share);
+ else if (IS_MNT_SHARED(mnt)) {
+ spin_lock(&mnt_pgid_lock);
+ ida_remove(&mnt_pgid_ida, mnt->mnt_pgid);
+ spin_unlock(&mnt_pgid_lock);
+ }
if (peer_mnt)
master = peer_mnt;
diff -puN fs/pnode.h~vfs-mountinfo-stable-peer-group-id fs/pnode.h
--- a/fs/pnode.h~vfs-mountinfo-stable-peer-group-id
+++ a/fs/pnode.h
@@ -25,6 +25,7 @@
void set_mnt_shared(struct vfsmount *);
void clear_mnt_shared(struct vfsmount *);
+void make_mnt_peer(struct vfsmount *, struct vfsmount *);
void change_mnt_propagation(struct vfsmount *, int);
int propagate_mnt(struct vfsmount *, struct dentry *, struct vfsmount *,
struct list_head *);
diff -puN include/linux/mount.h~vfs-mountinfo-stable-peer-group-id include/linux/mount.h
--- a/include/linux/mount.h~vfs-mountinfo-stable-peer-group-id
+++ a/include/linux/mount.h
@@ -57,6 +57,7 @@ struct vfsmount {
struct vfsmount *mnt_master; /* slave is on master->mnt_slave_list */
struct mnt_namespace *mnt_ns; /* containing namespace */
int mnt_id; /* mount identifier */
+ int mnt_pgid; /* peer group identifier */
/*
* We put mnt_count & mnt_expiry_mark at the end of struct vfsmount
* to let these frequently modified fields in a separate cache line
_
Patches currently in -mm which might be from mszeredi@xxxxxxx are
mm-rotate_reclaimable_page-cleanup.patch
vfs-mountinfo-mm-fix.patch
vfs-mountinfo-stable-peer-group-id.patch
vfs-mountinfo-show-dominating-group-id.patch
vfs-optimization-to-proc-pid-mountinfo-patch.patch
vfs-mountinfo-only-show-mounts-under-tasks-root.patch
vfs-remove-lives_below_in_same_fs.patch
mm-bdi-export-bdi-attributes-in-sysfs.patch
mm-bdi-export-bdi-attributes-in-sysfs-fix.patch
mm-bdi-export-bdi-attributes-in-sysfs-fix-2.patch
mm-bdi-export-bdi-attributes-in-sysfs-fix-3.patch
mm-bdi-export-bdi-attributes-in-sysfs-fix-4.patch
mm-bdi-export-bdi-attributes-in-sysfs-ia64-fix.patch
mm-bdi-expose-the-bdi-object-in-sysfs-for-nfs.patch
mm-bdi-expose-the-bdi-object-in-sysfs-for-nfs-fix.patch
mm-bdi-expose-the-bdi-object-in-sysfs-for-fuse.patch
mm-bdi-expose-the-bdi-object-in-sysfs-for-fuse-fix.patch
mm-bdi-allow-setting-a-minimum-for-the-bdi-dirty-limit.patch
mm-bdi-allow-setting-a-maximum-for-the-bdi-dirty-limit.patch
mm-bdi-allow-setting-a-maximum-for-the-bdi-dirty-limit-fix.patch
mm-bdi-move-statistics-to-debugfs.patch
mm-bdi-add-separate-writeback-accounting-capability.patch
mm-bdi-export-bdi_writeout_inc.patch
mm-bdi-export-bdi_writeout_inc-fix.patch
mm-add-nr_writeback_temp-counter.patch
mm-document-missing-fields-for-proc-meminfo.patch
fuse-support-writable-mmap.patch
fuse-support-writable-mmap-fix.patch
fuse-clean-up-setting-i_size-in-write.patch
fuse-implement-perform_write.patch
fuse-update-file-size-on-short-read.patch
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