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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>
hifive-unleashed-5.1
Andrew Morton 2012-04-05 14:25:07 -07:00 committed by Linus Torvalds
parent 703bf2d122
commit 0d08d7b7e1
1 changed files with 13 additions and 4 deletions
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17
fs/xattr.c
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@ -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;
}