kernfs: introduce kernfs_node_id

inode number and generation can identify a kernfs node. We are going to
export the identification by exportfs operations, so put ino and
generation into a separate structure. It's convenient when later patches
use the identification.

Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c
index b61a7efceb7aeddb38cb7faa0f4ae0c97af7b79f..89d1dc19340b09d4d9cd9db44ae3dfc9413bea98 100644 (file)
--- a/fs/kernfs/dir.c
+++ b/fs/kernfs/dir.c
@@ -539,7 +539,7 @@ void kernfs_put(struct kernfs_node *kn)
        }
        kfree(kn->iattr);
        spin_lock(&kernfs_idr_lock);
-       idr_remove(&root->ino_idr, kn->ino);
+       idr_remove(&root->ino_idr, kn->id.ino);
        spin_unlock(&kernfs_idr_lock);
        kmem_cache_free(kernfs_node_cache, kn);
 
@@ -645,8 +645,8 @@ static struct kernfs_node *__kernfs_new_node(struct kernfs_root *root,
        idr_preload_end();
        if (ret < 0)
                goto err_out2;
-       kn->ino = ret;
-       kn->generation = gen;
+       kn->id.ino = ret;
+       kn->id.generation = gen;
 
        /*
         * set ino first. This barrier is paired with atomic_inc_not_zero in
@@ -721,7 +721,7 @@ struct kernfs_node *kernfs_find_and_get_node_by_ino(struct kernfs_root *root,
         * before 'count'. So if 'count' is uptodate, 'ino' should be uptodate,
         * hence we can use 'ino' to filter stale node.
         */
-       if (kn->ino != ino)
+       if (kn->id.ino != ino)
                goto out;
        rcu_read_unlock();
 
@@ -1654,7 +1654,7 @@ static int kernfs_fop_readdir(struct file *file, struct dir_context *ctx)
                const char *name = pos->name;
                unsigned int type = dt_type(pos);
                int len = strlen(name);
-               ino_t ino = pos->ino;
+               ino_t ino = pos->id.ino;
 
                ctx->pos = pos->hash;
                file->private_data = pos;

diff --git a/fs/kernfs/file.c b/fs/kernfs/file.c
index 7f90d4de86b628ac15736330c1548a94ce488435..744192539010d8e08257acca766f43577ef49fab 100644 (file)
--- a/fs/kernfs/file.c
+++ b/fs/kernfs/file.c
@@ -895,7 +895,7 @@ repeat:
                 * have the matching @file available.  Look up the inodes
                 * and generate the events manually.
                 */
-               inode = ilookup(info->sb, kn->ino);
+               inode = ilookup(info->sb, kn->id.ino);
                if (!inode)
                        continue;
 
@@ -903,7 +903,7 @@ repeat:
                if (parent) {
                        struct inode *p_inode;
 
-                       p_inode = ilookup(info->sb, parent->ino);
+                       p_inode = ilookup(info->sb, parent->id.ino);
                        if (p_inode) {
                                fsnotify(p_inode, FS_MODIFY | FS_EVENT_ON_CHILD,
                                         inode, FSNOTIFY_EVENT_INODE, kn->name, 0);

diff --git a/fs/kernfs/inode.c b/fs/kernfs/inode.c
index 4c8b51085a865727521b634e71171266b769e47e..a34303981deb2cac6d39996e767b9e738d3c81df 100644 (file)
--- a/fs/kernfs/inode.c
+++ b/fs/kernfs/inode.c
@@ -220,7 +220,7 @@ static void kernfs_init_inode(struct kernfs_node *kn, struct inode *inode)
        inode->i_private = kn;
        inode->i_mapping->a_ops = &kernfs_aops;
        inode->i_op = &kernfs_iops;
-       inode->i_generation = kn->generation;
+       inode->i_generation = kn->id.generation;
 
        set_default_inode_attr(inode, kn->mode);
        kernfs_refresh_inode(kn, inode);
@@ -266,7 +266,7 @@ struct inode *kernfs_get_inode(struct super_block *sb, struct kernfs_node *kn)
 {
        struct inode *inode;
 
-       inode = iget_locked(sb, kn->ino);
+       inode = iget_locked(sb, kn->id.ino);
        if (inode && (inode->i_state & I_NEW))
                kernfs_init_inode(kn, inode);
 

diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index 710a005c6b7a652bb9c32b5457dbd64196f6f4a0..30c68773fd1e3cc30572bc69206aa6d03b3ca150 100644 (file)
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -543,7 +543,7 @@ static inline bool cgroup_is_populated(struct cgroup *cgrp)
 /* returns ino associated with a cgroup */
 static inline ino_t cgroup_ino(struct cgroup *cgrp)
 {
-       return cgrp->kn->ino;
+       return cgrp->kn->id.ino;
 }
 
 /* cft/css accessors for cftype->write() operation */

diff --git a/include/linux/kernfs.h b/include/linux/kernfs.h
index 8c00d28f468abf2aa31965fedab7032567162c8e..06a0c5913e1dbf7367bdb2dc47cb2d3e1a91e7bb 100644 (file)
--- a/include/linux/kernfs.h
+++ b/include/linux/kernfs.h
@@ -95,6 +95,15 @@ struct kernfs_elem_attr {
        struct kernfs_node      *notify_next;   /* for kernfs_notify() */
 };
 
+/* represent a kernfs node */
+union kernfs_node_id {
+       struct {
+               u32             ino;
+               u32             generation;
+       };
+       u64                     id;
+};
+
 /*
  * kernfs_node - the building block of kernfs hierarchy.  Each and every
  * kernfs node is represented by single kernfs_node.  Most fields are
@@ -131,11 +140,10 @@ struct kernfs_node {
 
        void                    *priv;
 
+       union kernfs_node_id    id;
        unsigned short          flags;
        umode_t                 mode;
-       unsigned int            ino;
        struct kernfs_iattrs    *iattr;
-       u32                     generation;
 };
 
 /*

diff --git a/include/trace/events/writeback.h b/include/trace/events/writeback.h
index 7bd8783a590ff99aed51310d4e4e4f05f2f7cb38..9b57f014d79d033336d7dc63a00972e5e9535230 100644 (file)
--- a/include/trace/events/writeback.h
+++ b/include/trace/events/writeback.h
@@ -136,7 +136,7 @@ DEFINE_EVENT(writeback_dirty_inode_template, writeback_dirty_inode,
 
 static inline unsigned int __trace_wb_assign_cgroup(struct bdi_writeback *wb)
 {
-       return wb->memcg_css->cgroup->kn->ino;
+       return wb->memcg_css->cgroup->kn->id.ino;
 }
 
 static inline unsigned int __trace_wbc_assign_cgroup(struct writeback_control *wbc)