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authorAndrew Morton <akpm@linux-foundation.org>2012-04-05 14:25:07 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-04-05 15:25:50 -0700
commit0d08d7b7e13b5060181b11ecdde82d8fda322123 (patch)
tree21f938ad3adafb2902358a5a234169229b3bcc16
parent703bf2d122c95412a30f72658c53ad6292867b0b (diff)
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>
-rw-r--r--fs/xattr.c17
1 files changed, 13 insertions, 4 deletions
diff --git a/fs/xattr.c b/fs/xattr.c
index a14d842ccb2..d14afbae3c1 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;
}