[PATCH 2/2] xfs: avoid dependency on Linux XATTR_SIZE_MAX

[Jan Tulak <jtulak@xxxxxxxxxx>]

Currently, we depends on Linux XATTR value for on disk
definition. 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.

This patch reflects a change in xfsprogs.

Signed-off-by: Jan Tulak <jtulak@xxxxxxxxxx>
---
 fs/xfs/libxfs/xfs_attr_remote.c |  2 +-
 fs/xfs/libxfs/xfs_format.h      | 10 +++++++++-
 fs/xfs/xfs_ioctl.c              |  4 ++--
 3 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_attr_remote.c b/fs/xfs/libxfs/xfs_attr_remote.c
index f38f9bd..5ab95ff 100644
--- a/fs/xfs/libxfs/xfs_attr_remote.c
+++ b/fs/xfs/libxfs/xfs_attr_remote.c
@@ -107,7 +107,7 @@ 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/fs/xfs/libxfs/xfs_format.h b/fs/xfs/libxfs/xfs_format.h
index 9590a06..8568de1 100644
--- a/fs/xfs/libxfs/xfs_format.h
+++ b/fs/xfs/libxfs/xfs_format.h
@@ -60,6 +60,14 @@ struct xfs_ifork;
 #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
  * shared superblock bit, which nobody knows what it does and so is 
unsupported.
@@ -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)
 
diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
index 0e692a6..9963f7c 100644
--- a/fs/xfs/xfs_ioctl.c
+++ b/fs/xfs/xfs_ioctl.c
@@ -455,7 +455,7 @@ xfs_attrmulti_attr_get(
        unsigned char           *kbuf;
        int                     error = -EFAULT;
 
-       if (*len > XATTR_SIZE_MAX)
+       if (*len > XFS_XATTR_SIZE_MAX)
                return -EINVAL;
        kbuf = kmem_zalloc_large(*len, KM_SLEEP);
        if (!kbuf)
@@ -485,7 +485,7 @@ xfs_attrmulti_attr_set(
 
        if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
                return -EPERM;
-       if (len > XATTR_SIZE_MAX)
+       if (len > XFS_XATTR_SIZE_MAX)
                return -EINVAL;
 
        kbuf = memdup_user(ubuf, len);
-- 
2.4.3