libxfs: avoid dependency on Linux XATTR_SIZE_MAX

Currently, we depends on Linux XATTR value for on disk
definitions. Which causes trouble on other platforms and
maybe also if this value was to change.

Fix it by creating a custom definition independent from
those in Linux (although with the same values), so it is OK
with the be16 fields used for holding these attributes.

Signed-off-by: Jan Tulak <jtulak@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

diff --git a/libxfs/xfs_attr_remote.c b/libxfs/xfs_attr_remote.c
index 3b3c24b6cddfd8bdbbe5b31b35485dafef07ee49..39ab350f937581adadad6349e9b5090261425d54 100644 (file)
--- a/libxfs/xfs_attr_remote.c
+++ b/libxfs/xfs_attr_remote.c
@@ -102,7 +102,7 @@ xfs_attr3_rmt_verify(
        if (be32_to_cpu(rmt->rm_bytes) > fsbsize - sizeof(*rmt))
                return false;
        if (be32_to_cpu(rmt->rm_offset) +
-                               be32_to_cpu(rmt->rm_bytes) > XATTR_SIZE_MAX)
+                               be32_to_cpu(rmt->rm_bytes) > XFS_XATTR_SIZE_MAX)
                return false;
        if (rmt->rm_owner == 0)
                return false;

diff --git a/libxfs/xfs_format.h b/libxfs/xfs_format.h
index 3c98635f262250a501c6304f073ea7439debdfd4..946bcd16476511448a3119b2f96a661b09de8073 100644 (file)
--- a/libxfs/xfs_format.h
+++ b/libxfs/xfs_format.h
@@ -59,6 +59,14 @@ struct xfs_ifork;
 #define        XFS_SB_VERSION_BORGBIT          0x4000  /* ASCII only case-insens. */
 #define        XFS_SB_VERSION_MOREBITSBIT      0x8000
 
+/*
+ * The size of a single extended attribute on disk is limited by
+ * the size of index values within the attribute entries themselves.
+ * These are be16 fields, so we can only support attribute data
+ * sizes up to 2^16 bytes in length.
+ */
+#define XFS_XATTR_SIZE_MAX (1 << 16)
+
 /*
  * Supported feature bit list is just all bits in the versionnum field because
  * we've used them all up and understand them all. Except, of course, for the
@@ -1483,7 +1491,7 @@ struct xfs_acl {
  */
 #define XFS_ACL_MAX_ENTRIES(mp)        \
        (xfs_sb_version_hascrc(&mp->m_sb) \
-               ?  (XATTR_SIZE_MAX - sizeof(struct xfs_acl)) / \
+               ?  (XFS_XATTR_SIZE_MAX - sizeof(struct xfs_acl)) / \
                                                sizeof(struct xfs_acl_entry) \
                : 25)