From 0d08d7b7e13b5060181b11ecdde82d8fda322123 Mon Sep 17 00:00:00 2001
From: Andrew Morton <akpm@linux-foundation.org>
Date: Thu, 5 Apr 2012 14:25:07 -0700
Subject: [PATCH] fs/xattr.c:listxattr(): fall back to vmalloc() if kmalloc()
failed
This allocation can be as large as 64k. As David points out, "falling
back to vmalloc here is much better solution than failing to retreive
the attribute - it will work no matter how fragmented memory gets. That
means we don't get incomplete backups occurring after days or months of
uptime and successful backups".
Cc: Dave Chinner <david@fromorbit.com>
Cc: Dave Jones <davej@codemonkey.org.uk>
Cc: David Rientjes <rientjes@google.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
fs/xattr.c | 17 +++++++++++++----
1 file changed, 13 insertions(+), 4 deletions(-)
diff --git a/fs/xattr.c b/fs/xattr.c
index a14d842ccb21..d14afbae3c13 100644
--- a/fs/xattr.c
+++ b/fs/xattr.c
@@ -19,8 +19,9 @@
#include <linux/export.h>
#include <linux/fsnotify.h>
#include <linux/audit.h>
-#include <asm/uaccess.h>
+#include <linux/vmalloc.h>
+#include <asm/uaccess.h>
/*
* Check permissions for extended attribute access. This is a bit complicated
@@ -492,13 +493,18 @@ listxattr(struct dentry *d, char __user *list, size_t size)
{
ssize_t error;
char *klist = NULL;
+ char *vlist = NULL; /* If non-NULL, we used vmalloc() */
if (size) {
if (size > XATTR_LIST_MAX)
size = XATTR_LIST_MAX;
klist = kmalloc(size, __GFP_NOWARN | GFP_KERNEL);
- if (!klist)
- return -ENOMEM;
+ if (!klist) {
+ vlist = vmalloc(size);
+ if (!vlist)
+ return -ENOMEM;
+ klist = vlist;
+ }
}
error = vfs_listxattr(d, klist, size);
@@ -510,7 +516,10 @@ listxattr(struct dentry *d, char __user *list, size_t size)
than XATTR_LIST_MAX bytes. Not possible. */
error = -E2BIG;
}
- kfree(klist);
+ if (vlist)
+ vfree(vlist);
+ else
+ kfree(klist);
return error;
}
--
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