Commit a3a065e3 authored by Nick Piggin's avatar Nick Piggin Committed by Al Viro
Browse files

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: default avatarMiklos Szeredi <mszeredi@suse.cz>
Signed-off-by: default avatarNick Piggin <npiggin@suse.de>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent b9aff027

fs/anon_inodes.c

+0 −13
Original line number Diff line number Diff line
@@ -35,16 +35,6 @@ static int anon_inodefs_get_sb(struct file_system_type *fs_type, int flags, 
			     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().

 */
@@ -60,7 +50,6 @@ static struct file_system_type anon_inode_fs_type = { 
	.kill_sb	= kill_anon_super,

};

static const struct dentry_operations anon_inodefs_dentry_operations = {

	.d_delete	= anon_inodefs_delete_dentry,

	.d_dname	= anon_inodefs_dname,

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



	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	/* Do not publish this dentry inside the global dentry hash table */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);



	error = -ENFILE;

fs/pipe.c

+0 −18
Original line number Diff line number Diff line
@@ -906,17 +906,6 @@ void free_pipe_info(struct inode *inode) 
}



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



static const struct dentry_operations pipefs_dentry_operations = {

	.d_delete	= pipefs_delete_dentry,

	.d_dname	= pipefs_dname,

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



	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);



	err = -ENFILE;

net/socket.c

+0 −19
Original line number Diff line number Diff line
@@ -312,18 +312,6 @@ static struct file_system_type sock_fs_type = { 
	.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().

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



static const struct dentry_operations sockfs_dentry_operations = {

	.d_delete = sockfs_delete_dentry,

	.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.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));

	SOCK_INODE(sock)->i_fop = &socket_file_ops;

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