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Gu Zhengbcrl
Gu Zheng
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bcrl
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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. Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com> Signed-off-by: Benjamin LaHaise <bcrl@kvack.org>
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‎fs/anon_inodes.c

Lines changed: 66 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -108,6 +108,72 @@ static struct file_system_type anon_inode_fs_type = {
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.kill_sb = kill_anon_super,
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};
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/**
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* anon_inode_getfile_private - creates a new file instance by hooking it up to an
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* anonymous inode, and a dentry that describe the "class"
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* of the file
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*
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* @name: [in] name of the "class" of the new file
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* @fops: [in] file operations for the new file
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* @priv: [in] private data for the new file (will be file's private_data)
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* @flags: [in] flags
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*
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*
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* Similar to anon_inode_getfile, but each file holds a single inode.
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*
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*/
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struct file *anon_inode_getfile_private(const char *name,
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const struct file_operations *fops,
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void *priv, int flags)
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{
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struct qstr this;
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struct path path;
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struct file *file;
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struct inode *inode;
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if (fops->owner && !try_module_get(fops->owner))
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return ERR_PTR(-ENOENT);
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inode = anon_inode_mkinode(anon_inode_mnt->mnt_sb);
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if (IS_ERR(inode)) {
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file = ERR_PTR(-ENOMEM);
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goto err_module;
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}
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/*
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* Link the inode to a directory entry by creating a unique name
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* using the inode sequence number.
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*/
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file = ERR_PTR(-ENOMEM);
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this.name = name;
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this.len = strlen(name);
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this.hash = 0;
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path.dentry = d_alloc_pseudo(anon_inode_mnt->mnt_sb, &this);
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if (!path.dentry)
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goto err_module;
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path.mnt = mntget(anon_inode_mnt);
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d_instantiate(path.dentry, inode);
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file = alloc_file(&path, OPEN_FMODE(flags), fops);
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if (IS_ERR(file))
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goto err_dput;
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file->f_mapping = inode->i_mapping;
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file->f_flags = flags & (O_ACCMODE | O_NONBLOCK);
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file->private_data = priv;
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return file;
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err_dput:
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path_put(&path);
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err_module:
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module_put(fops->owner);
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return file;
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}
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EXPORT_SYMBOL_GPL(anon_inode_getfile_private);
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/**
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* anon_inode_getfile - creates a new file instance by hooking it up to an
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* anonymous inode, and a dentry that describe the "class"

‎include/linux/anon_inodes.h

Lines changed: 3 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -13,6 +13,9 @@ struct file_operations;
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struct file *anon_inode_getfile(const char *name,
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const struct file_operations *fops,
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void *priv, int flags);
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struct file *anon_inode_getfile_private(const char *name,
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const struct file_operations *fops,
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void *priv, int flags);
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int anon_inode_getfd(const char *name, const struct file_operations *fops,
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void *priv, int flags);
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