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fs/anon_inode: Introduce a new lib function anon_inode_getfile_private()

PATCH RESEND Superseded Gu Zheng 2 participants 3 messages Jul 16, 2013 – Jul 17, 2013

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Gu Zheng

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PATCH RESEND 1/2 fs/anon_inode: Introduce a new lib function anon_inode_getfile_private()

Introduce a new lib function anon_inode_getfile_private(), it creates a new file instance by hooking it up to an anonymous inode, and a dentry that describe the "class" of the file, similar to anon_inode_getfile(), but each file holds a single inode. Furthermore, anyone who wants to create a private anon file will benefit from this change.

---
 fs/anon_inodes.c            |   66 +++++++++++++++++++++++++++++++++++++++++++
 include/linux/anon_inodes.h |    3 ++
 2 files changed, 69 insertions(+), 0 deletions(-)
fs/anon_inodes.c +66 -0
index 47a65df..85c9618 100644
@@ -109,6 +109,72 @@ static struct file_system_type anon_inode_fs_type = {
 };
 
 /**
+ * anon_inode_getfile_private - creates a new file instance by hooking it up to an
+ *                      anonymous inode, and a dentry that describe the "class"
+ *                      of the file
+ *
+ * @name:    [in]    name of the "class" of the new file
+ * @fops:    [in]    file operations for the new file
+ * @priv:    [in]    private data for the new file (will be file's private_data)
+ * @flags:   [in]    flags
+ *
+ *
+ * Similar to anon_inode_getfile, but each file holds a single inode.
+ *
+ */
+struct file *anon_inode_getfile_private(const char *name,
+					const struct file_operations *fops,
+					void *priv, int flags)
+{
+	struct qstr this;
+	struct path path;
+	struct file *file;
+	struct inode *inode;
+
+	if (fops->owner && !try_module_get(fops->owner))
+		return ERR_PTR(-ENOENT);
+
+	inode = anon_inode_mkinode(anon_inode_mnt->mnt_sb);
+	if (IS_ERR(inode)) {
+		file = ERR_PTR(-ENOMEM);
+		goto err_module;
+	}
+
+	/*
+	 * Link the inode to a directory entry by creating a unique name
+	 * using the inode sequence number.
+	 */
+	file = ERR_PTR(-ENOMEM);
+	this.name = name;
+	this.len = strlen(name);
+	this.hash = 0;
+	path.dentry = d_alloc_pseudo(anon_inode_mnt->mnt_sb, &this);
+	if (!path.dentry)
+		goto err_module;
+
+	path.mnt = mntget(anon_inode_mnt);
+
+	d_instantiate(path.dentry, inode);
+
+	file = alloc_file(&path, OPEN_FMODE(flags), fops);
+	if (IS_ERR(file))
+		goto err_dput;
+
+	file->f_mapping = inode->i_mapping;
+	file->f_flags = flags & (O_ACCMODE | O_NONBLOCK);
+	file->private_data = priv;
+
+	return file;
+
+err_dput:
+	path_put(&path);
+err_module:
+	module_put(fops->owner);
+	return file;
+}
+EXPORT_SYMBOL_GPL(anon_inode_getfile_private);
+
+/**
  * anon_inode_getfile - creates a new file instance by hooking it up to an
  *                      anonymous inode, and a dentry that describe the "class"
  *                      of the file
include/linux/anon_inodes.h +3 -0
index 8013a45..cf573c2 100644
@@ -13,6 +13,9 @@ struct file_operations;
 struct file *anon_inode_getfile(const char *name,
 				const struct file_operations *fops,
 				void *priv, int flags);
+struct file *anon_inode_getfile_private(const char *name,
+				const struct file_operations *fops,
+				void *priv, int flags);
 int anon_inode_getfd(const char *name, const struct file_operations *fops,
 		     void *priv, int flags);
 
Signature · 7 lines
1.7.7

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#1 lore raw
Quoted 9 lines · Gu Zheng

Introduce a new lib function anon_inode_getfile_private(), it creates a new file instance by hooking it up to an anonymous inode, and a dentry that describe the "class" of the file, similar to anon_inode_getfile(), but each file holds a single inode. Furthermore, anyone who wants to create a private anon file will benefit from this change.

Please don't add my Signed-off-by when I have never even seen or reviewed a patch -- that is completely unacceptable. Second, I don't think this patch is suitable for 3.11, as it has not seen much testing outside of one test program I had written. It's a long standing bug, so it isn't urgent to get the fix into the tree. That said, it did pass a few tests I ran last night, so it is probably suitable for the -next tree.

As for patch 1, it looks okay to me, but will need Al Viro's signoff.

-ben

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"Thought is the essence of where you are now."

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author
#2 lore raw

Hi Ben,

Quoted 8 lines · Benjamin LaHaise
Quoted 7 lines · Gu Zheng

Introduce a new lib function anon_inode_getfile_private(), it creates a new file instance by hooking it up to an anonymous inode, and a dentry that describe the "class" of the file, similar to anon_inode_getfile(), but each file holds a single inode. Furthermore, anyone who wants to create a private anon file will benefit from this change.

Quoted 5 lines
Quoted 2 lines

Please don't add my Signed-off-by when I have never even seen or reviewed a patch -- that is completely unacceptable.

Sorry for my reckless action, I'll remember your reminder.:)

Quoted 5 lines

Second, I don't think this
patch is suitable for 3.11, as it has not seen much testing outside of one test program I had written. It's a long standing bug, so it isn't urgent to get the fix into the tree. That said, it did pass a few tests I ran last night, so it is probably suitable for the -next tree.

Thanks for your test.:)

Regards,
Gu

Quoted 4 lines

As for patch 1, it looks okay to me, but will need Al Viro's signoff.

-ben

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