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Blame 0103-hw-9pfs-Fix-errno-value-for-xattr-functions.patch

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From 6f7e1d2bddb5a0a1c65f6f02467460d6edbcc901 Mon Sep 17 00:00:00 2001
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From: "Daniel P. Berrange" <berrange@redhat.com>
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Date: Tue, 1 Oct 2013 12:28:17 +0100
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Subject: [PATCH] hw/9pfs: Fix errno value for xattr functions
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If there is no operation driver for the xattr type the
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functions return '-1' and set errno to '-EOPNOTSUPP'.
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When the calling code sets 'ret = -errno' this turns
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into a large positive number.
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In Linux 3.11, the kernel has switched to using 9p
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version 9p2000.L, instead of 9p2000.u, which enables
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support for xattr operations. This on its own is harmless,
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but for another change which makes it request the xattr
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with a name 'security.capability'.
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The result is that the guest sees a succesful return
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of 95 bytes of data, instead of a failure with errno
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set to 95. Since the kernel expects a maximum of 20
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bytes for an xattr return this gets translated to the
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unexpected errno ERANGE.
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This all means that when running a binary off a 9p fs
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in 3.11 kernels you get a fun result of:
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  # ./date
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  sh: ./date: Numerical result out of range
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The only workaround is to pass 'version=9p2000.u' when
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mounting the 9p fs in the guest, to disable all use of
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xattrs.
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Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
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---
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 hw/9pfs/virtio-9p-xattr.c | 6 +++---
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 1 file changed, 3 insertions(+), 3 deletions(-)
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diff --git a/hw/9pfs/virtio-9p-xattr.c b/hw/9pfs/virtio-9p-xattr.c
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index 90ae565..3fae557 100644
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--- a/hw/9pfs/virtio-9p-xattr.c
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+++ b/hw/9pfs/virtio-9p-xattr.c
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@@ -36,7 +36,7 @@ ssize_t v9fs_get_xattr(FsContext *ctx, const char *path,
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     if (xops) {
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         return xops->getxattr(ctx, path, name, value, size);
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     }
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-    errno = -EOPNOTSUPP;
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+    errno = EOPNOTSUPP;
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     return -1;
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 }
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@@ -123,7 +123,7 @@ int v9fs_set_xattr(FsContext *ctx, const char *path, const char *name,
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     if (xops) {
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         return xops->setxattr(ctx, path, name, value, size, flags);
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     }
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-    errno = -EOPNOTSUPP;
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+    errno = EOPNOTSUPP;
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     return -1;
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 }
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@@ -135,7 +135,7 @@ int v9fs_remove_xattr(FsContext *ctx,
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     if (xops) {
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         return xops->removexattr(ctx, path, name);
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     }
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-    errno = -EOPNOTSUPP;
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+    errno = EOPNOTSUPP;
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     return -1;
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 }