From: ebiederm@xmission.com (Eric W. Biederman)
To: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org,
linux-mm@kvack.org, linux-fsdevel@vger.kernel.org,
Al Viro <viro@ZenIV.linux.org.uk>,
Hugh Dickins <hugh@veritas.com>, Tejun Heo <tj@kernel.org>,
Alexey Dobriyan <adobriyan@gmail.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Alan Cox <alan@lxorguk.ukuu.org.uk>,
Greg Kroah-Hartman <gregkh@suse.de>
Subject: [RFC][PATCH 8/9] vfs: Implement generic revoked file operations
Date: Sat, 11 Apr 2009 05:13:22 -0700 [thread overview]
Message-ID: <m1prfj5qxp.fsf@fess.ebiederm.org> (raw)
In-Reply-To: <m1skkf761y.fsf@fess.ebiederm.org> (Eric W. Biederman's message of "Sat\, 11 Apr 2009 05\:01\:29 -0700")
revoked_file_ops is a set of file operations designed to be used
when a files backing store has been removed.
revoked_file_ops return 0 from reads (aka EOF). Tell poll the file is
always ready for I/O and return -EIO from all other operations.
This is designed to allow userspace to gracefully file descriptors
that enter this unusable state.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
---
fs/Makefile | 2 +-
fs/revoked_file.c | 181 ++++++++++++++++++++++++++++++++++++++++++++++++++++
include/linux/fs.h | 2 +
3 files changed, 184 insertions(+), 1 deletions(-)
create mode 100644 fs/revoked_file.c
diff --git a/fs/Makefile b/fs/Makefile
index af6d047..7787ddd 100644
--- a/fs/Makefile
+++ b/fs/Makefile
@@ -11,7 +11,7 @@ obj-y := open.o read_write.o file_table.o super.o \
attr.o bad_inode.o file.o filesystems.o namespace.o \
seq_file.o xattr.o libfs.o fs-writeback.o \
pnode.o drop_caches.o splice.o sync.o utimes.o \
- stack.o fs_struct.o
+ stack.o fs_struct.o revoked_file.o
ifeq ($(CONFIG_BLOCK),y)
obj-y += buffer.o bio.o block_dev.o direct-io.o mpage.o ioprio.o
diff --git a/fs/revoked_file.c b/fs/revoked_file.c
new file mode 100644
index 0000000..9936693
--- /dev/null
+++ b/fs/revoked_file.c
@@ -0,0 +1,181 @@
+/*
+ * linux/fs/revoked_file.c
+ *
+ * Copyright (C) 1997, Stephen Tweedie
+ *
+ * Provide stub functions for unreadable inodes
+ *
+ * Fabian Frederick : August 2003 - All file operations assigned to EIO
+ *
+ * Eric Biederman : 8 April 2008 - Derivied from bad_inode.c
+ */
+
+#include <linux/fs.h>
+#include <linux/module.h>
+#include <linux/stat.h>
+#include <linux/time.h>
+#include <linux/namei.h>
+#include <linux/poll.h>
+
+static loff_t revoked_file_llseek(struct file *file, loff_t offset, int origin)
+{
+ return -EIO;
+}
+
+static ssize_t revoked_file_read(struct file *filp, char __user *buf,
+ size_t size, loff_t *ppos)
+{
+ return 0;
+}
+
+static ssize_t revoked_file_write(struct file *filp, const char __user *buf,
+ size_t siz, loff_t *ppos)
+{
+ return -EIO;
+}
+
+static ssize_t revoked_file_aio_read(struct kiocb *iocb, const struct iovec *iov,
+ unsigned long nr_segs, loff_t pos)
+{
+ return 0;
+}
+
+static ssize_t revoked_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
+ unsigned long nr_segs, loff_t pos)
+{
+ return -EIO;
+}
+
+static int revoked_file_readdir(struct file *filp, void *dirent, filldir_t filldir)
+{
+ return -EIO;
+}
+
+static unsigned int revoked_file_poll(struct file *filp, poll_table *wait)
+{
+ return POLLIN | POLLOUT | POLLERR | POLLRDNORM | POLLWRNORM;
+}
+
+static int revoked_file_ioctl (struct inode *inode, struct file *filp,
+ unsigned int cmd, unsigned long arg)
+{
+ return -EIO;
+}
+
+static long revoked_file_unlocked_ioctl(struct file *file, unsigned cmd,
+ unsigned long arg)
+{
+ return -EIO;
+}
+
+static long revoked_file_compat_ioctl(struct file *file, unsigned int cmd,
+ unsigned long arg)
+{
+ return -EIO;
+}
+
+static int revoked_file_mmap(struct file *file, struct vm_area_struct *vma)
+{
+ return -EIO;
+}
+
+static int revoked_file_open(struct inode *inode, struct file *filp)
+{
+ return -EIO;
+}
+
+static int revoked_file_flush(struct file *file, fl_owner_t id)
+{
+ return 0;
+}
+
+static int revoked_file_release(struct inode *inode, struct file *filp)
+{
+ return 0;
+}
+
+static int revoked_file_fsync(struct file *file, struct dentry *dentry,
+ int datasync)
+{
+ return -EIO;
+}
+
+static int revoked_file_aio_fsync(struct kiocb *iocb, int datasync)
+{
+ return -EIO;
+}
+
+static int revoked_file_fasync(int fd, struct file *filp, int on)
+{
+ return -EIO;
+}
+
+static int revoked_file_lock(struct file *file, int cmd, struct file_lock *fl)
+{
+ return -EIO;
+}
+
+static ssize_t revoked_file_sendpage(struct file *file, struct page *page,
+ int off, size_t len, loff_t *pos, int more)
+{
+ return -EIO;
+}
+
+static unsigned long revoked_file_get_unmapped_area(struct file *file,
+ unsigned long addr, unsigned long len,
+ unsigned long pgoff, unsigned long flags)
+{
+ return -EIO;
+}
+
+static int revoked_file_check_flags(int flags)
+{
+ return -EIO;
+}
+
+static int revoked_file_flock(struct file *filp, int cmd, struct file_lock *fl)
+{
+ return -EIO;
+}
+
+static ssize_t revoked_file_splice_write(struct pipe_inode_info *pipe,
+ struct file *out, loff_t *ppos, size_t len,
+ unsigned int flags)
+{
+ return -EIO;
+}
+
+static ssize_t revoked_file_splice_read(struct file *in, loff_t *ppos,
+ struct pipe_inode_info *pipe, size_t len,
+ unsigned int flags)
+{
+ return -EIO;
+}
+
+const struct file_operations revoked_file_ops =
+{
+ .llseek = revoked_file_llseek,
+ .read = revoked_file_read,
+ .write = revoked_file_write,
+ .aio_read = revoked_file_aio_read,
+ .aio_write = revoked_file_aio_write,
+ .readdir = revoked_file_readdir,
+ .poll = revoked_file_poll,
+ .ioctl = revoked_file_ioctl,
+ .unlocked_ioctl = revoked_file_unlocked_ioctl,
+ .compat_ioctl = revoked_file_compat_ioctl,
+ .mmap = revoked_file_mmap,
+ .open = revoked_file_open,
+ .flush = revoked_file_flush,
+ .release = revoked_file_release,
+ .fsync = revoked_file_fsync,
+ .aio_fsync = revoked_file_aio_fsync,
+ .fasync = revoked_file_fasync,
+ .lock = revoked_file_lock,
+ .sendpage = revoked_file_sendpage,
+ .get_unmapped_area = revoked_file_get_unmapped_area,
+ .check_flags = revoked_file_check_flags,
+ .flock = revoked_file_flock,
+ .splice_write = revoked_file_splice_write,
+ .splice_read = revoked_file_splice_read,
+};
diff --git a/include/linux/fs.h b/include/linux/fs.h
index a82a2ea..2fb0871 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -896,6 +896,8 @@ extern int fops_substitute(struct file *file, const struct file_operations *f_op
extern void inode_fops_substitute(struct inode *inode,
const struct file_operations *f_op, struct vm_operations_struct *vm_ops);
+extern const struct file_operations revoked_file_ops;
+
extern struct mutex files_lock;
#define file_list_lock() mutex_lock(&files_lock);
#define file_list_unlock() mutex_unlock(&files_lock);
--
1.6.1.2.350.g88cc
--
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next prev parent reply other threads:[~2009-04-11 12:13 UTC|newest]
Thread overview: 99+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-04-11 12:01 [RFC][PATCH 0/9] File descriptor hot-unplug support Eric W. Biederman
2009-04-11 12:03 ` [RFC][PATCH 1/9] mm: Introduce remap_file_mappings Eric W. Biederman
2009-04-11 12:05 ` [RFC][PATCH 2/9] mm: Implement generic support for revoking a mapping Eric W. Biederman
2009-04-11 12:06 ` [RFC][PATCH 3/9] sysfs: Use remap_file_mappings Eric W. Biederman
2009-04-11 12:07 ` [RFC][PATCH 4/9] vfs: Generalize the file_list Eric W. Biederman
2009-04-11 12:08 ` [RFC][PATCH 5/9] vfs: Introduce basic infrastructure for revoking a file Eric W. Biederman
2009-04-14 22:12 ` Jonathan Corbet
2009-04-15 2:55 ` Eric W. Biederman
2009-04-11 12:10 ` [RFC][PATCH 6/9] vfs: Utilize fops_read_lock where appropriate Eric W. Biederman
2009-04-11 12:11 ` [RFC][PATCH 7/9] vfs: Optimize fops_read_lock Eric W. Biederman
2009-04-11 12:13 ` Eric W. Biederman [this message]
2009-04-12 18:56 ` [RFC][PATCH 8/9] vfs: Implement generic revoked file operations Jamie Lokier
2009-04-12 20:04 ` Eric W. Biederman
2009-04-12 20:31 ` Jamie Lokier
2009-04-12 21:53 ` Eric W. Biederman
2009-04-12 20:54 ` Eric W. Biederman
2009-04-12 21:02 ` Jamie Lokier
2009-04-12 23:06 ` Eric W. Biederman
2009-04-11 12:14 ` [RFC][PATCH 9/9] proc: Use the generic vfs revoke facility that now exists Eric W. Biederman
2009-04-11 15:58 ` [RFC][PATCH 0/9] File descriptor hot-unplug support Al Viro
2009-04-11 16:49 ` Eric W. Biederman
2009-04-11 16:56 ` Al Viro
2009-04-11 23:57 ` Eric W. Biederman
2009-04-12 20:21 ` Eric W. Biederman
2009-04-14 3:16 ` Tejun Heo
2009-04-14 7:39 ` Eric W. Biederman
2009-04-14 7:45 ` Tejun Heo
2009-04-14 8:27 ` Eric W. Biederman
2009-04-14 8:49 ` Tejun Heo
2009-04-14 15:07 ` Jamie Lokier
2009-04-14 19:09 ` Eric W. Biederman
2009-06-01 21:45 ` [PATCH 0/23] File descriptor hot-unplug support v2 Eric W. Biederman
2009-06-01 21:50 ` [PATCH 01/23] mm: Introduce revoke_file_mappings Eric W. Biederman
2009-06-01 22:25 ` Andrew Morton
2009-06-02 0:12 ` Eric W. Biederman
2009-06-01 21:50 ` [PATCH 02/23] vfs: Implement unpoll_file Eric W. Biederman
2009-06-06 8:08 ` Al Viro
2009-06-01 21:50 ` [PATCH 03/23] vfs: Generalize the file_list Eric W. Biederman
2009-06-02 7:06 ` Nick Piggin
2009-06-05 19:33 ` Eric W. Biederman
2009-06-09 10:38 ` Nick Piggin
2009-06-09 18:38 ` Eric W. Biederman
2009-06-10 6:05 ` Nick Piggin
2009-06-01 21:50 ` [PATCH 04/23] vfs: Introduce infrastructure for revoking a file Eric W. Biederman
2009-06-02 5:16 ` Pekka Enberg
2009-06-02 6:51 ` Eric W. Biederman
2009-06-02 7:08 ` Pekka Enberg
2009-06-02 7:14 ` Nick Piggin
2009-06-02 17:06 ` Linus Torvalds
2009-06-02 20:52 ` Eric W. Biederman
2009-06-03 6:37 ` Nick Piggin
2009-06-02 22:56 ` Eric W. Biederman
2009-06-03 6:38 ` Nick Piggin
2009-06-05 9:03 ` Miklos Szeredi
2009-06-05 19:06 ` Eric W. Biederman
2009-06-01 21:50 ` [PATCH 05/23] vfs: Teach lseek to use file_hotplug_lock Eric W. Biederman
2009-06-01 21:50 ` [PATCH 06/23] vfs: Teach read/write to use file_hotplug_read_lock Eric W. Biederman
2009-06-01 21:50 ` [PATCH 07/23] vfs: Teach sendfile,splice,tee,and vmsplice to use file_hotplug_lock Eric W. Biederman
2009-06-03 23:39 ` Badari Pulavarty
2009-06-05 19:37 ` Eric W. Biederman
2009-06-01 21:50 ` [PATCH 08/23] vfs: Teach readdir " Eric W. Biederman
2009-06-01 21:50 ` [PATCH 09/23] vfs: Teach poll and select " Eric W. Biederman
2009-06-01 21:50 ` [PATCH 10/23] vfs: Teach do_path_lookup " Eric W. Biederman
2009-06-01 21:50 ` [PATCH 11/23] mm: Teach mmap " Eric W. Biederman
2009-06-01 21:50 ` [PATCH 12/23] vfs: Teach fcntl " Eric W. Biederman
2009-06-01 21:50 ` [PATCH 13/23] vfs: Teach ioctl " Eric W. Biederman
2009-06-01 21:50 ` [PATCH 14/23] vfs: Teach flock " Eric W. Biederman
2009-06-01 21:50 ` [PATCH 15/23] vfs: Teach fallocate, and filp_close " Eric W. Biederman
2009-06-01 21:50 ` [PATCH 16/23] vfs: Teach fstatfs, fstatfs64, ftruncate, fchdir, fchmod, fchown " Eric W. Biederman
2009-06-01 21:50 ` [PATCH 17/23] proc: Teach /proc/<pid>/fd " Eric W. Biederman
2009-06-01 21:50 ` [PATCH 18/23] vfs: Teach epoll " Eric W. Biederman
2009-06-02 16:51 ` Davide Libenzi
2009-06-02 21:23 ` Eric W. Biederman
2009-06-02 21:52 ` Davide Libenzi
2009-06-02 22:51 ` Eric W. Biederman
2009-06-03 14:57 ` Davide Libenzi
2009-06-03 20:53 ` Eric W. Biederman
2009-06-04 0:50 ` Davide Libenzi
2009-06-04 1:42 ` Eric W. Biederman
2009-06-01 21:50 ` [PATCH 19/23] eventpoll: Fix comment Eric W. Biederman
2009-06-01 21:50 ` [PATCH 20/23] vfs: Teach aio to use file_hotplug_lock Eric W. Biederman
2009-06-01 21:50 ` [PATCH 21/23] vfs: Teach fsync " Eric W. Biederman
2009-06-01 21:50 ` [PATCH 22/23] vfs: Teach fadvice to file_hotplug_lock Eric W. Biederman
2009-06-01 21:50 ` [PATCH 23/23] vfs: Teach readahead to use the file_hotplug_lock Eric W. Biederman
2009-06-03 23:25 ` Badari Pulavarty
2009-06-06 8:03 ` [PATCH 0/23] File descriptor hot-unplug support v2 Al Viro
2009-06-08 9:41 ` Miklos Szeredi
2009-06-08 10:24 ` Jamie Lokier
2009-06-08 16:29 ` Al Viro
2009-06-08 16:44 ` Miklos Szeredi
2009-06-08 17:50 ` Al Viro
2009-06-08 18:01 ` Linus Torvalds
2009-06-08 18:50 ` Al Viro
2009-06-08 19:18 ` Linus Torvalds
2009-06-09 6:42 ` Eric W. Biederman
2009-06-09 10:52 ` Nick Piggin
2009-06-09 5:50 ` Miklos Szeredi
2009-06-09 6:31 ` Eric W. Biederman
2009-06-09 6:22 ` Eric W. Biederman
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