The patch titled
vfs: mountinfo: add mount ID
has been added to the -mm tree. Its filename is
vfs-mountinfo-add-mount-id.patch
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------------------------------------------------------
Subject: vfs: mountinfo: add mount ID
From: Miklos Szeredi <mszeredi@xxxxxxx>
Add a unique ID to each vfsmount using the IDR infrastructure. The
identifiers are reused after the vfsmount is freed.
Signed-off-by: Miklos Szeredi <mszeredi@xxxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Ram Pai <linuxram@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/namespace.c | 34 ++++++++++++++++++++++++++++++++++
include/linux/mount.h | 1 +
2 files changed, 35 insertions(+)
diff -puN fs/namespace.c~vfs-mountinfo-add-mount-id fs/namespace.c
--- a/fs/namespace.c~vfs-mountinfo-add-mount-id
+++ a/fs/namespace.c
@@ -27,6 +27,7 @@
#include <linux/mount.h>
#include <linux/ramfs.h>
#include <linux/log2.h>
+#include <linux/idr.h>
#include <asm/uaccess.h>
#include <asm/unistd.h>
#include "pnode.h"
@@ -39,6 +40,7 @@
__cacheline_aligned_in_smp DEFINE_SPINLOCK(vfsmount_lock);
static int event;
+static DEFINE_IDA(mnt_id_ida);
static struct list_head *mount_hashtable __read_mostly;
static struct kmem_cache *mnt_cache __read_mostly;
@@ -58,10 +60,41 @@ static inline unsigned long hash(struct
#define MNT_WRITER_UNDERFLOW_LIMIT -(1<<16)
+static int mnt_alloc_id(struct vfsmount *mnt)
+{
+ int res;
+
+ retry:
+ spin_lock(&vfsmount_lock);
+ res = ida_get_new(&mnt_id_ida, &mnt->mnt_id);
+ spin_unlock(&vfsmount_lock);
+ if (res == -EAGAIN) {
+ if (ida_pre_get(&mnt_id_ida, GFP_KERNEL))
+ goto retry;
+ res = -ENOMEM;
+ }
+ return res;
+}
+
+static void mnt_free_id(struct vfsmount *mnt)
+{
+ spin_lock(&vfsmount_lock);
+ ida_remove(&mnt_id_ida, mnt->mnt_id);
+ spin_unlock(&vfsmount_lock);
+}
+
struct vfsmount *alloc_vfsmnt(const char *name)
{
struct vfsmount *mnt = kmem_cache_zalloc(mnt_cache, GFP_KERNEL);
if (mnt) {
+ int err;
+
+ err = mnt_alloc_id(mnt);
+ if (err) {
+ kmem_cache_free(mnt_cache, mnt);
+ return NULL;
+ }
+
atomic_set(&mnt->mnt_count, 1);
INIT_LIST_HEAD(&mnt->mnt_hash);
INIT_LIST_HEAD(&mnt->mnt_child);
@@ -353,6 +386,7 @@ EXPORT_SYMBOL(simple_set_mnt);
void free_vfsmnt(struct vfsmount *mnt)
{
kfree(mnt->mnt_devname);
+ mnt_free_id(mnt);
kmem_cache_free(mnt_cache, mnt);
}
diff -puN include/linux/mount.h~vfs-mountinfo-add-mount-id include/linux/mount.h
--- a/include/linux/mount.h~vfs-mountinfo-add-mount-id
+++ a/include/linux/mount.h
@@ -56,6 +56,7 @@ struct vfsmount {
struct list_head mnt_slave; /* slave list entry */
struct vfsmount *mnt_master; /* slave is on master->mnt_slave_list */
struct mnt_namespace *mnt_ns; /* containing namespace */
+ int mnt_id; /* mount 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-add-dentry_path.patch
vfs-mountinfo-add-seq_file_root.patch
vfs-mountinfo-add-mount-id.patch
vfs-mountinfo-add-mount-peer-group-id.patch
vfs-mountinfo-allow-using-process-root.patch
vfs-mountinfo-add-proc-pid-mountinfo.patch
vfs-mountinfo-show-dominating-group-id.patch
vfs-mountinfo-mm-fix.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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