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Commit a3a065e3 authored Nov 18, 2009 by Nick Piggin Committed by Al Viro Dec 17, 2009

fs: no games with DCACHE_UNHASHED



Filesystems outside the regular namespace do not have to clear DCACHE_UNHASHED
in order to have a working /proc/$pid/fd/XXX. Nothing in proc prevents the
fd link from being used if its dentry is not in the hash.

Also, it does not get put into the dcache hash if DCACHE_UNHASHED is clear;
that depends on the filesystem calling d_add or d_rehash.

So delete the misleading comments and needless code.

Acked-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

parent b9aff027

fs/anon_inodes.c

+0 −13

Original line number	Original line	Diff line number	Diff line
	@@ -35,16 +35,6 @@ static int anon_inodefs_get_sb(struct file_system_type *fs_type, int flags,
	mnt);		mnt);
	}		}

	static int anon_inodefs_delete_dentry(struct dentry *dentry)
	{
	/*
	* We faked vfs to believe the dentry was hashed when we created it.
	* Now we restore the flag so that dput() will work correctly.
	*/
	dentry->d_flags \|= DCACHE_UNHASHED;
	return 1;
	}

	/*		/*
	* anon_inodefs_dname() is called from d_path().		* anon_inodefs_dname() is called from d_path().
	*/		*/
	@@ -60,7 +50,6 @@ static struct file_system_type anon_inode_fs_type = {
	.kill_sb = kill_anon_super,		.kill_sb = kill_anon_super,
	};		};
	static const struct dentry_operations anon_inodefs_dentry_operations = {		static const struct dentry_operations anon_inodefs_dentry_operations = {
	.d_delete = anon_inodefs_delete_dentry,
	.d_dname = anon_inodefs_dname,		.d_dname = anon_inodefs_dname,
	};		};

	@@ -129,8 +118,6 @@ struct file anon_inode_getfile(const char name,
	atomic_inc(&anon_inode_inode->i_count);		atomic_inc(&anon_inode_inode->i_count);

	path.dentry->d_op = &anon_inodefs_dentry_operations;		path.dentry->d_op = &anon_inodefs_dentry_operations;
	/* Do not publish this dentry inside the global dentry hash table */
	path.dentry->d_flags &= ~DCACHE_UNHASHED;
	d_instantiate(path.dentry, anon_inode_inode);		d_instantiate(path.dentry, anon_inode_inode);

	error = -ENFILE;		error = -ENFILE;

fs/pipe.c

+0 −18

Original line number	Original line	Diff line number	Diff line
	@@ -906,17 +906,6 @@ void free_pipe_info(struct inode *inode)
	}		}

	static struct vfsmount *pipe_mnt __read_mostly;		static struct vfsmount *pipe_mnt __read_mostly;
	static int pipefs_delete_dentry(struct dentry *dentry)
	{
	/*
	* At creation time, we pretended this dentry was hashed
	* (by clearing DCACHE_UNHASHED bit in d_flags)
	* At delete time, we restore the truth : not hashed.
	* (so that dput() can proceed correctly)
	*/
	dentry->d_flags \|= DCACHE_UNHASHED;
	return 0;
	}

	/*		/*
	* pipefs_dname() is called from d_path().		* pipefs_dname() is called from d_path().
	@@ -928,7 +917,6 @@ static char pipefs_dname(struct dentry dentry, char *buffer, int buflen)
	}		}

	static const struct dentry_operations pipefs_dentry_operations = {		static const struct dentry_operations pipefs_dentry_operations = {
	.d_delete = pipefs_delete_dentry,
	.d_dname = pipefs_dname,		.d_dname = pipefs_dname,
	};		};

	@@ -989,12 +977,6 @@ struct file *create_write_pipe(int flags)
	path.mnt = mntget(pipe_mnt);		path.mnt = mntget(pipe_mnt);

	path.dentry->d_op = &pipefs_dentry_operations;		path.dentry->d_op = &pipefs_dentry_operations;
	/*
	* We dont want to publish this dentry into global dentry hash table.
	* We pretend dentry is already hashed, by unsetting DCACHE_UNHASHED
	* This permits a working /proc/$pid/fd/XXX on pipes
	*/
	path.dentry->d_flags &= ~DCACHE_UNHASHED;
	d_instantiate(path.dentry, inode);		d_instantiate(path.dentry, inode);

	err = -ENFILE;		err = -ENFILE;

net/socket.c

+0 −19

Original line number	Original line	Diff line number	Diff line
	@@ -312,18 +312,6 @@ static struct file_system_type sock_fs_type = {
	.kill_sb = kill_anon_super,		.kill_sb = kill_anon_super,
	};		};

	static int sockfs_delete_dentry(struct dentry *dentry)
	{
	/*
	* At creation time, we pretended this dentry was hashed
	* (by clearing DCACHE_UNHASHED bit in d_flags)
	* At delete time, we restore the truth : not hashed.
	* (so that dput() can proceed correctly)
	*/
	dentry->d_flags \|= DCACHE_UNHASHED;
	return 0;
	}

	/*		/*
	* sockfs_dname() is called from d_path().		* sockfs_dname() is called from d_path().
	*/		*/
	@@ -334,7 +322,6 @@ static char sockfs_dname(struct dentry dentry, char *buffer, int buflen)
	}		}

	static const struct dentry_operations sockfs_dentry_operations = {		static const struct dentry_operations sockfs_dentry_operations = {
	.d_delete = sockfs_delete_dentry,
	.d_dname = sockfs_dname,		.d_dname = sockfs_dname,
	};		};

	@@ -374,12 +361,6 @@ static int sock_alloc_file(struct socket sock, struct file *f, int flags)
	path.mnt = mntget(sock_mnt);		path.mnt = mntget(sock_mnt);

	path.dentry->d_op = &sockfs_dentry_operations;		path.dentry->d_op = &sockfs_dentry_operations;
	/*
	* We dont want to push this dentry into global dentry hash table.
	* We pretend dentry is already hashed, by unsetting DCACHE_UNHASHED
	* This permits a working /proc/$pid/fd/XXX on sockets
	*/
	path.dentry->d_flags &= ~DCACHE_UNHASHED;
	d_instantiate(path.dentry, SOCK_INODE(sock));		d_instantiate(path.dentry, SOCK_INODE(sock));
	SOCK_INODE(sock)->i_fop = &socket_file_ops;		SOCK_INODE(sock)->i_fop = &socket_file_ops;