Merge tag 'xfs-for-linus-3.17-rc1' of git://oss.sgi.com/xfs/xfs

Pull xfs update from Dave Chinner:
 "This update contains:
   - conversion of the XFS core to pass negative error numbers
   - restructing of core XFS code that is shared with userspace to
     fs/xfs/libxfs
   - introduction of sysfs interface for XFS
   - bulkstat refactoring
   - demand driven speculative preallocation removal
   - XFS now always requires 64 bit sectors to be configured
   - metadata verifier changes to ensure CRCs are calculated during log
     recovery
   - various minor code cleanups
   - miscellaneous bug fixes

  The diffstat is kind of noisy because of the restructuring of the code
  to make kernel/userspace code sharing simpler, along with the XFS wide
  change to use the standard negative error return convention (at last!)"

* tag 'xfs-for-linus-3.17-rc1' of git://oss.sgi.com/xfs/xfs: (45 commits)
  xfs: fix coccinelle warnings
  xfs: flush both inodes in xfs_swap_extents
  xfs: fix swapext ilock deadlock
  xfs: kill xfs_vnode.h
  xfs: kill VN_MAPPED
  xfs: kill VN_CACHED
  xfs: kill VN_DIRTY()
  xfs: dquot recovery needs verifiers
  xfs: quotacheck leaves dquot buffers without verifiers
  xfs: ensure verifiers are attached to recovered buffers
  xfs: catch buffers written without verifiers attached
  xfs: avoid false quotacheck after unclean shutdown
  xfs: fix rounding error of fiemap length parameter
  xfs: introduce xfs_bulkstat_ag_ichunk
  xfs: require 64-bit sector_t
  xfs: fix uflags detection at xfs_fs_rm_xquota
  xfs: remove XFS_IS_OQUOTA_ON macros
  xfs: tidy up xfs_set_inode32
  xfs: allow inode allocations in post-growfs disk space
  xfs: mark xfs_qm_quotacheck as static
  ...

1 files changed, 63 insertions, 0 deletions

diff --git a/fs/xfs/libxfs/xfs_cksum.h b/fs/xfs/libxfs/xfs_cksum.h
new file mode 100644
index 000000000000..fad1676ad8cd
--- /dev/null
+++ b/fs/xfs/libxfs/xfs_cksum.h
@@ -0,0 +1,63 @@
+#ifndef _XFS_CKSUM_H
+#define _XFS_CKSUM_H 1
+
+#define XFS_CRC_SEED	(~(__uint32_t)0)
+
+/*
+ * Calculate the intermediate checksum for a buffer that has the CRC field
+ * inside it.  The offset of the 32bit crc fields is passed as the
+ * cksum_offset parameter.
+ */
+static inline __uint32_t
+xfs_start_cksum(char *buffer, size_t length, unsigned long cksum_offset)
+{
+	__uint32_t zero = 0;
+	__uint32_t crc;
+
+	/* Calculate CRC up to the checksum. */
+	crc = crc32c(XFS_CRC_SEED, buffer, cksum_offset);
+
+	/* Skip checksum field */
+	crc = crc32c(crc, &zero, sizeof(__u32));
+
+	/* Calculate the rest of the CRC. */
+	return crc32c(crc, &buffer[cksum_offset + sizeof(__be32)],
+		      length - (cksum_offset + sizeof(__be32)));
+}
+
+/*
+ * Convert the intermediate checksum to the final ondisk format.
+ *
+ * The CRC32c calculation uses LE format even on BE machines, but returns the
+ * result in host endian format. Hence we need to byte swap it back to LE format
+ * so that it is consistent on disk.
+ */
+static inline __le32
+xfs_end_cksum(__uint32_t crc)
+{
+	return ~cpu_to_le32(crc);
+}
+
+/*
+ * Helper to generate the checksum for a buffer.
+ */
+static inline void
+xfs_update_cksum(char *buffer, size_t length, unsigned long cksum_offset)
+{
+	__uint32_t crc = xfs_start_cksum(buffer, length, cksum_offset);
+
+	*(__le32 *)(buffer + cksum_offset) = xfs_end_cksum(crc);
+}
+
+/*
+ * Helper to verify the checksum for a buffer.
+ */
+static inline int
+xfs_verify_cksum(char *buffer, size_t length, unsigned long cksum_offset)
+{
+	__uint32_t crc = xfs_start_cksum(buffer, length, cksum_offset);
+
+	return *(__le32 *)(buffer + cksum_offset) == xfs_end_cksum(crc);
+}
+
+#endif /* _XFS_CKSUM_H */