[RFC 26/26] union-mount: Debug code

From: Jan Blunck
Date: Mon Jul 30 2007 - 12:24:46 EST

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Some debugging code itself.

Signed-off-by: Jan Blunck <jblunck@xxxxxxx>
---
fs/namei.c | 26 ++++++++++++++++++++++++++
fs/union.c | 27 +++++++++++++++++++++++++++
include/linux/namei.h | 4 ++++
3 files changed, 57 insertions(+)

--- a/fs/namei.c
+++ b/fs/namei.c
@@ -32,6 +32,7 @@
#include <linux/fcntl.h>
#include <linux/namei.h>
#include <linux/union.h>
+#include <linux/union_debug.h>
#include <asm/namei.h>
#include <asm/uaccess.h>

@@ -1794,11 +1795,15 @@ int hash_lookup_union(struct nameidata *
struct path safe = { .dentry = nd->dentry, .mnt = nd->mnt };
int res ;

+ UM_DEBUG_LOOKUP("name = \"%*s\"\n", name->len, name->name);
+
pathget(&safe);
res = __hash_lookup_topmost(nd, name, path);
if (res)
goto out;

+ UM_DEBUG_LOOKUP_DENTRY(path->dentry);
+
/* only directories can be part of a union stack */
if (!path->dentry->d_inode ||
!S_ISDIR(path->dentry->d_inode->i_mode))
@@ -1813,6 +1818,7 @@ int hash_lookup_union(struct nameidata *
goto out;
}

+ UM_DEBUG_LOOKUP_DENTRY(path->dentry);
out:
path_release(nd);
nd->dentry = safe.dentry;
@@ -2765,6 +2771,8 @@ out_freename:
kfree(name.name);
out:
pathput(&safe);
+ UM_DEBUG("err = %d\n", err);
+ UM_DEBUG_DENTRY(dentry);
return err;
}

@@ -2802,6 +2810,9 @@ int vfs_unlink_whiteout(struct inode *di
}
mutex_unlock(&dentry->d_inode->i_mutex);

+ UM_DEBUG("err = %d\n", error);
+ UM_DEBUG_DENTRY(dentry);
+
/*
* We can call dentry_iput() since nobody could actually do something
* useful with a whiteout. So dropping the reference to the inode
@@ -3490,6 +3501,10 @@ int vfs_rename_union(struct nameidata *o
struct dentry *dentry;
int error;

+ UM_DEBUG_DENTRY(old->dentry);
+ UM_DEBUG_DENTRY(new->dentry);
+/* return -EPERM; */
+
if (old->dentry->d_inode == new->dentry->d_inode)
return 0;

@@ -3530,6 +3545,9 @@ int vfs_rename_union(struct nameidata *o

/* possibly delete the existing new file */
if ((newnd->dentry == new->dentry->d_parent) && new->dentry->d_inode) {
+ UM_DEBUG("unlink:\n");
+ UM_DEBUG_DENTRY(new->dentry);
+
/* FIXME: inode may be truncated while we hold a lock */
error = vfs_unlink(new_dir, new->dentry);
if (error)
@@ -3540,6 +3558,9 @@ int vfs_rename_union(struct nameidata *o
if (IS_ERR(dentry))
goto freename;

+ UM_DEBUG("new target:\n");
+ UM_DEBUG_DENTRY(new->dentry);
+
dput(new->dentry);
new->dentry = dentry;
}
@@ -3554,6 +3575,10 @@ int vfs_rename_union(struct nameidata *o
error = PTR_ERR(dentry);
if (IS_ERR(dentry))
goto freename;
+
+ UM_DEBUG("whiteout:\n");
+ UM_DEBUG_DENTRY(dentry);
+
error = vfs_whiteout(old_dir, dentry);
dput(dentry);

@@ -3567,6 +3592,7 @@ int vfs_rename_union(struct nameidata *o
*/
freename:
kfree(old_name.name);
+ UM_DEBUG("err = %d\n", error);
return error;
}

--- a/fs/union.c
+++ b/fs/union.c
@@ -18,6 +18,7 @@
#include <linux/hash.h>
#include <linux/fs.h>
#include <linux/union.h>
+#include <linux/union_debug.h>
#include <linux/module.h>
#include <linux/file.h>
#include <linux/mm.h>
@@ -253,6 +254,9 @@ int append_to_union(struct vfsmount *mnt

BUG_ON(!IS_MNT_UNION(mnt));

+ UM_DEBUG_DENTRY(dentry);
+ UM_DEBUG_DENTRY(dest_dentry);
+
this = union_alloc(dentry, mnt, dest_dentry, dest_mnt);
if (!this)
return -ENOMEM;
@@ -822,6 +826,8 @@ int union_relookup_topmost(struct nameid
char *kbuf, *name;
struct nameidata this;

+ UM_DEBUG_DENTRY(nd->dentry);
+
kbuf = (char *)__get_free_page(GFP_KERNEL);
if (!kbuf)
return -ENOMEM;
@@ -838,6 +844,7 @@ int union_relookup_topmost(struct nameid
path_release(nd);
nd->dentry = this.dentry;
nd->mnt = this.mnt;
+ UM_DEBUG_DENTRY(nd->dentry);

/*
* the nd->flags should be unchanged
@@ -846,6 +853,7 @@ int union_relookup_topmost(struct nameid
nd->um_flags &= ~LAST_LOWLEVEL;
free_page:
free_page((unsigned long)kbuf);
+ UM_DEBUG("err = %d\n", err);
return err;
}

@@ -895,6 +903,8 @@ struct dentry *union_create_topmost(stru
if (IS_ERR(dentry))
goto out_unlock;

+ UM_DEBUG_DENTRY(dentry);
+
switch (mode & S_IFMT) {
case S_IFREG:
/*
@@ -916,6 +926,9 @@ struct dentry *union_create_topmost(stru
dentry = ERR_PTR(res);
goto out_unlock;
}
+
+ UM_DEBUG_DENTRY(dentry);
+
break;
case S_IFDIR:
res = vfs_mkdir(parent->d_inode, dentry, mode);
@@ -925,6 +938,8 @@ struct dentry *union_create_topmost(stru
goto out_unlock;
}

+ UM_DEBUG_DENTRY(dentry);
+
res = append_to_union(nd->mnt, dentry, path->mnt,
path->dentry);
if (res) {
@@ -944,6 +959,7 @@ struct dentry *union_create_topmost(stru

out_unlock:
mutex_unlock(&parent->d_inode->i_mutex);
+ UM_DEBUG("err = %d\n", IS_ERR(dentry) ? PTR_ERR(dentry) : 0);
return dentry;
}

@@ -980,9 +996,14 @@ static int union_copy_file(struct dentry
if (ret >= 0)
ret = 0;
fput_new:
+ UM_DEBUG("new_dentry:\n");
+ UM_DEBUG_DENTRY(new_dentry);
fput(new_file);
fput_old:
+ UM_DEBUG("old_dentry:\n");
+ UM_DEBUG_DENTRY(old_dentry);
fput(old_file);
+ UM_DEBUG("err = %d\n", ret);
return ret;
}

@@ -1059,6 +1080,8 @@ int union_copyup(struct nameidata *nd, i
if (!S_ISREG(nd->dentry->d_inode->i_mode))
return 0;

+ UM_DEBUG_DENTRY(nd->dentry);
+
/* safe the name for hash_lookup_union() */
this.len = nd->dentry->d_name.len;
this.hash = nd->dentry->d_name.hash;
@@ -1084,6 +1107,8 @@ int union_copyup(struct nameidata *nd, i
if (err)
return err;

+ UM_DEBUG_DENTRY(path.dentry);
+
err = -ENOENT;
if (!path.dentry->d_inode)
goto exit_dput;
@@ -1106,9 +1131,11 @@ int union_copyup(struct nameidata *nd, i
}

path_to_nameidata(&path, nd);
+ UM_DEBUG("err = 0\n");
return 0;

exit_dput:
dput_path(&path, nd);
+ UM_DEBUG("err = %d\n", err);
return err;
}
--- a/include/linux/namei.h
+++ b/include/linux/namei.h
@@ -117,17 +117,20 @@ static inline char *nd_get_link(struct n

static inline void pathget(struct path *path)
{
+ WARN_ON(path->dentry->d_sb != path->mnt->mnt_sb);
mntget(path->mnt);
dget(path->dentry);
}

static inline void pathput(struct path *path)
{
+ WARN_ON(path->dentry->d_sb != path->mnt->mnt_sb);
dput(path->dentry);
mntput(path->mnt);
}
static inline void dput_path(struct path *path, struct nameidata *nd)
{
+ WARN_ON(path->dentry->d_sb != path->mnt->mnt_sb);
dput(path->dentry);
if (path->mnt != nd->mnt)
mntput(path->mnt);
@@ -135,6 +138,7 @@ static inline void dput_path(struct path

static inline void path_to_nameidata(struct path *path, struct nameidata *nd)
{
+ WARN_ON(path->dentry->d_sb != path->mnt->mnt_sb);
dput(nd->dentry);
if (nd->mnt != path->mnt)
mntput(nd->mnt);

--

-
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Next message: Jan Blunck: "[RFC 00/26] VFS based Union Mount (V2)"
Previous message: Jan Blunck: "[RFC 22/26] union-mount: white-out changes for copy-on-open"
In reply to: Jan Blunck: "[RFC 22/26] union-mount: white-out changes for copy-on-open"
Next in thread: Jan Blunck: "[RFC 08/26] VFS: Export lives_below_in_same_fs()"
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