Re: [PATCH 1/2] fs/anon_inode: Introduce a new lib function, anon_inode_getfile_private()

From: Gu Zheng
Date: Thu Jul 11 2013 - 06:15:25 EST


ping...


On 07/08/2013 06:38 PM, Gu Zheng wrote:

> 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.
>
> Signed-off-by: Gu Zheng <guz.fnst@xxxxxxxxxxxxxx>
> Signed-off-by: Benjamin LaHaise <bcrl@xxxxxxxxx>
> ---
> fs/anon_inodes.c | 66 +++++++++++++++++++++++++++++++++++++++++++
> include/linux/anon_inodes.h | 3 ++
> 2 files changed, 69 insertions(+), 0 deletions(-)
>
> diff --git a/fs/anon_inodes.c b/fs/anon_inodes.c
> index 47a65df..85c9618 100644
> --- a/fs/anon_inodes.c
> +++ b/fs/anon_inodes.c
> @@ -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
> diff --git a/include/linux/anon_inodes.h b/include/linux/anon_inodes.h
> index 8013a45..cf573c2 100644
> --- a/include/linux/anon_inodes.h
> +++ b/include/linux/anon_inodes.h
> @@ -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);
>


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