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 1/9] mm: Introduce remap_file_mappings.
Date: Sat, 11 Apr 2009 05:03:23 -0700 [thread overview]
Message-ID: <m1myan75ys.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")
>From 819088d701e3a821db8e08ed83d46c00c27cc772 Mon Sep 17 00:00:00 2001
From: Eric W. Biederman <ebiederm@xmission.com>
Date: Tue, 7 Apr 2009 19:35:07 -0700
Subject:
When the backing store of a file becomes inaccessible we need a function
to remove that file from the page tables and arrange for page faults
to receive SIGBUS until the file is unmapped.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
---
include/linux/mm.h | 1 +
mm/memory.c | 87 ++++++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 88 insertions(+), 0 deletions(-)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index bff1f0d..96d8342 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -807,6 +807,7 @@ static inline void unmap_shared_mapping_range(struct address_space *mapping,
extern int vmtruncate(struct inode * inode, loff_t offset);
extern int vmtruncate_range(struct inode * inode, loff_t offset, loff_t end);
+extern void remap_file_mappings(struct file *file, struct vm_operations_struct *vm_ops);
#ifdef CONFIG_MMU
extern int handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma,
diff --git a/mm/memory.c b/mm/memory.c
index cf6873e..dcd0a3c 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2325,6 +2325,93 @@ void unmap_mapping_range(struct address_space *mapping,
}
EXPORT_SYMBOL(unmap_mapping_range);
+static void remap_vma(struct vm_area_struct *vma,
+ struct vm_operations_struct *vm_ops)
+{
+ struct file *file = vma->vm_file;
+ struct address_space *mapping = file->f_mapping;
+ unsigned long start_addr, end_addr, size;
+ struct mm_struct *mm;
+
+ start_addr = vma->vm_start;
+ end_addr = vma->vm_end;
+
+ /* Has this vma already been processed? */
+ if (vma->vm_ops == vm_ops)
+ return;
+
+ /* Switch out the locks so I can maninuplate this under the mm sem.
+ * Needed so I can call vm_ops->close.
+ */
+ mm = vma->vm_mm;
+ atomic_inc(&mm->mm_users);
+ spin_unlock(&mapping->i_mmap_lock);
+
+ /* Block page faults and other code modifying the mm. */
+ down_write(&mm->mmap_sem);
+
+ /* Lookup a vma for my file address */
+ vma = find_vma(mm, start_addr);
+ if (vma->vm_file != file)
+ goto out;
+ if (vma->vm_ops == vm_ops)
+ goto out;
+
+ start_addr = vma->vm_start;
+ end_addr = vma->vm_end;
+ size = end_addr - start_addr;
+
+ /* Unmap the vma */
+ zap_page_range(vma, start_addr, size, NULL);
+
+ /* Close the vma */
+ if (vma->vm_ops && vma->vm_ops->close)
+ vma->vm_ops->close(vma);
+
+ /* Repurpose the vma */
+ vma->vm_private_data = NULL;
+ vma->vm_ops = vm_ops;
+ if (vm_ops->open)
+ vm_ops->open(vma);
+out:
+ up_write(&mm->mmap_sem);
+ spin_lock(&mapping->i_mmap_lock);
+}
+
+void remap_file_mappings(struct file *file, struct vm_operations_struct *vm_ops)
+{
+ /* After file->f_ops has been changed update the vmas */
+ struct address_space *mapping = file->f_mapping;
+ struct vm_area_struct *vma;
+ struct prio_tree_iter iter;
+
+ spin_lock(&mapping->i_mmap_lock);
+
+restart_tree:
+ vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, 0, ULONG_MAX) {
+ /* Skip quickly over vmas that do not need to be touched */
+ if (vma->vm_file != file)
+ continue;
+ if (vma->vm_ops == vm_ops)
+ continue;
+ remap_vma(vma, vm_ops);
+ goto restart_tree;
+ }
+
+restart_list:
+ list_for_each_entry(vma, &mapping->i_mmap_nonlinear, shared.vm_set.list) {
+ /* Skip quickly over vmas that do not need to be touched */
+ if (vma->vm_file != file)
+ continue;
+ if (vma->vm_ops == vm_ops)
+ continue;
+ remap_vma(vma, vm_ops);
+ goto restart_list;
+ }
+
+ spin_unlock(&mapping->i_mmap_lock);
+}
+
/**
* vmtruncate - unmap mappings "freed" by truncate() syscall
* @inode: inode of the file used
--
1.6.1.2.350.g88cc
next prev parent reply other threads:[~2009-04-11 12:03 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 ` Eric W. Biederman [this message]
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 ` [RFC][PATCH 8/9] vfs: Implement generic revoked file operations Eric W. Biederman
2009-04-12 18:56 ` 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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