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Subject[PATCH 20/32] Unionfs: lower nameidata support
Date
From: Erez Zadok <ezk@cs.sunysb.edu>

Create and free custom nameidata structures, and pass them to lower file
systems when needed via vfs_create. (This code will get updated when/if
nameidata is split into an intent structure and a VFS-level only structure.)

Signed-off-by: Erez Zadok <ezk@cs.sunysb.edu>
Signed-off-by: Josef 'Jeff' Sipek <jsipek@cs.sunysb.edu>
---
fs/unionfs/copyup.c | 8 ++++++-
fs/unionfs/lookup.c | 58 +++++++++++++++++++++++++++++++++++++++++++++++++++
fs/unionfs/rename.c | 15 +++++++++++-
fs/unionfs/subr.c | 14 ++++++++++-
fs/unionfs/union.h | 2 +
5 files changed, 92 insertions(+), 5 deletions(-)
diff --git a/fs/unionfs/copyup.c b/fs/unionfs/copyup.c
index 9c476cd..4c45790 100644
--- a/fs/unionfs/copyup.c
+++ b/fs/unionfs/copyup.c
@@ -177,19 +177,25 @@ static int __copyup_ndentry(struct dentry *old_lower_dentry,
run_sioq(__unionfs_mknod, &args);
err = args.err;
} else if (S_ISREG(old_mode)) {
+ struct nameidata nd;
+ err = init_lower_nd(&nd, LOOKUP_CREATE);
+ if (err < 0)
+ goto out;
+ args.create.nd = &nd;
args.create.parent = new_lower_parent_dentry->d_inode;
args.create.dentry = new_lower_dentry;
args.create.mode = old_mode;
- args.create.nd = NULL;

run_sioq(__unionfs_create, &args);
err = args.err;
+ release_lower_nd(&nd, err);
} else {
printk(KERN_ERR "unionfs: unknown inode type %d\n",
old_mode);
BUG();
}

+out:
return err;
}

diff --git a/fs/unionfs/lookup.c b/fs/unionfs/lookup.c
index d05daa5..152d421 100644
--- a/fs/unionfs/lookup.c
+++ b/fs/unionfs/lookup.c
@@ -564,3 +564,61 @@ void update_bstart(struct dentry *dentry)
unionfs_set_lower_dentry_idx(dentry, bindex, NULL);
}
}
+
+
+/*
+ * Initialize a nameidata structure (the intent part) we can pass to a lower
+ * file system. Returns 0 on success or -error (only -ENOMEM possible).
+ * Inside that nd structure, this function may also return an allocated
+ * struct file (for open intents). The caller, when done with this nd, must
+ * kfree the intent file (using release_lower_nd).
+ */
+int init_lower_nd(struct nameidata *nd, unsigned int flags)
+{
+ int err = 0;
+#ifdef ALLOC_LOWER_ND_FILE
+ /*
+ * XXX: one day we may need to have the lower return an open file
+ * for us. It is not needed in 2.6.23-rc1 for nfs2/nfs3, but may
+ * very well be needed for nfs4.
+ */
+ struct file *file;
+#endif /* ALLOC_LOWER_ND_FILE */
+
+ memset(nd, 0, sizeof(struct nameidata));
+
+ switch (flags) {
+ case LOOKUP_CREATE:
+ nd->flags = LOOKUP_CREATE;
+ nd->intent.open.flags = FMODE_READ | FMODE_WRITE | O_CREAT;
+#ifdef ALLOC_LOWER_ND_FILE
+ file = kzalloc(sizeof(struct file), GFP_KERNEL);
+ if (!file) {
+ err = -ENOMEM;
+ break; /* exit switch statement and thus return */
+ }
+ nd->intent.open.file = file;
+#endif /* ALLOC_LOWER_ND_FILE */
+ break;
+ default:
+ /*
+ * We should never get here, for now.
+ * We can add new cases here later on.
+ */
+ BUG();
+ break;
+ }
+
+ return err;
+}
+
+void release_lower_nd(struct nameidata *nd, int err)
+{
+ if (!nd->intent.open.file)
+ return;
+ if (!err)
+ release_open_intent(nd);
+#ifdef ALLOC_LOWER_ND_FILE
+ kfree(nd->intent.open.file);
+#endif /* ALLOC_LOWER_ND_FILE */
+}
diff --git a/fs/unionfs/rename.c b/fs/unionfs/rename.c
index acf829a..a02d678 100644
--- a/fs/unionfs/rename.c
+++ b/fs/unionfs/rename.c
@@ -256,10 +256,20 @@ static int do_unionfs_rename(struct inode *old_dir,
*/
if ((old_bstart != old_bend) || (do_copyup != -1)) {
struct dentry *lower_parent;
- BUG_ON(!wh_old || wh_old->d_inode || bwh_old < 0);
+ struct nameidata nd;
+ if (!wh_old || wh_old->d_inode || bwh_old < 0) {
+ printk(KERN_ERR "unionfs: rename error "
+ "(wh_old=%p/%p bwh_old=%d)\n", wh_old,
+ (wh_old ? wh_old->d_inode : NULL), bwh_old);
+ err = -EIO;
+ goto out;
+ }
+ err = init_lower_nd(&nd, LOOKUP_CREATE);
+ if (err < 0)
+ goto out;
lower_parent = lock_parent(wh_old);
local_err = vfs_create(lower_parent->d_inode, wh_old, S_IRUGO,
- NULL);
+ &nd);
unlock_dir(lower_parent);
if (!local_err)
set_dbopaque(old_dentry, bwh_old);
@@ -272,6 +282,7 @@ static int do_unionfs_rename(struct inode *old_dir,
"the source in rename!\n");
err = -EIO;
}
+ release_lower_nd(&nd, local_err);
}

out:
diff --git a/fs/unionfs/subr.c b/fs/unionfs/subr.c
index 5db9e62..b7e7904 100644
--- a/fs/unionfs/subr.c
+++ b/fs/unionfs/subr.c
@@ -29,6 +29,7 @@ int create_whiteout(struct dentry *dentry, int start)
struct dentry *lower_dir_dentry;
struct dentry *lower_dentry;
struct dentry *lower_wh_dentry;
+ struct nameidata nd;
char *name = NULL;
int err = -EINVAL;

@@ -82,14 +83,18 @@ int create_whiteout(struct dentry *dentry, int start)
goto out;
}

+ err = init_lower_nd(&nd, LOOKUP_CREATE);
+ if (err < 0)
+ goto out;
lower_dir_dentry = lock_parent(lower_wh_dentry);
if (!(err = is_robranch_super(dentry->d_sb, bindex)))
err = vfs_create(lower_dir_dentry->d_inode,
lower_wh_dentry,
~current->fs->umask & S_IRWXUGO,
- NULL);
+ &nd);
unlock_dir(lower_dir_dentry);
dput(lower_wh_dentry);
+ release_lower_nd(&nd, err);

if (!err || !IS_COPYUP_ERR(err))
break;
@@ -151,6 +156,7 @@ int make_dir_opaque(struct dentry *dentry, int bindex)
int err = 0;
struct dentry *lower_dentry, *diropq;
struct inode *lower_dir;
+ struct nameidata nd;

lower_dentry = unionfs_lower_dentry_idx(dentry, bindex);
lower_dir = lower_dentry->d_inode;
@@ -165,10 +171,14 @@ int make_dir_opaque(struct dentry *dentry, int bindex)
goto out;
}

+ err = init_lower_nd(&nd, LOOKUP_CREATE);
+ if (err < 0)
+ goto out;
if (!diropq->d_inode)
- err = vfs_create(lower_dir, diropq, S_IRUGO, NULL);
+ err = vfs_create(lower_dir, diropq, S_IRUGO, &nd);
if (!err)
set_dbopaque(dentry, bindex);
+ release_lower_nd(&nd, err);

dput(diropq);

diff --git a/fs/unionfs/union.h b/fs/unionfs/union.h
index 0fa8ae0..9f3e68a 100644
--- a/fs/unionfs/union.h
+++ b/fs/unionfs/union.h
@@ -248,6 +248,8 @@ static inline void unionfs_double_lock_dentry(struct dentry *d1,
extern int new_dentry_private_data(struct dentry *dentry);
extern void free_dentry_private_data(struct dentry *dentry);
extern void update_bstart(struct dentry *dentry);
+extern int init_lower_nd(struct nameidata *nd, unsigned int flags);
+extern void release_lower_nd(struct nameidata *nd, int err);

/*
* EXTERNALS:
--
1.5.2.2.238.g7cbf2f2
-
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