[XFS] superblock endianess annotations

Creates a new xfs_dsb_t that is __be annotated and keeps xfs_sb_t for the
incore one. xfs_xlatesb is renamed to xfs_sb_to_disk and only handles the
incore -> disk conversion. A new helper xfs_sb_from_disk handles the other
direction and doesn't need the slightly hacky table-driven approach
because we only ever read the full sb from disk.

The handling of shared r/o filesystems has been buggy on little endian
system and fixing this required shuffling around of some code in that
area.

SGI-PV: 968563
SGI-Modid: xfs-linux-melb:xfs-kern:29477a

Signed-off-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: David Chinner <dgc@sgi.com>
Signed-off-by: Tim Shimmin <tes@sgi.com>

1 files changed, 65 insertions, 3 deletions

diff --git a/fs/xfs/xfs_sb.h b/fs/xfs/xfs_sb.h
index ef42537a607a..94660b1a6ccc 100644
--- a/fs/xfs/xfs_sb.h
+++ b/fs/xfs/xfs_sb.h
@@ -87,8 +87,10 @@ struct xfs_mount;
         (XFS_SB_VERSION2_OKREALFBITS |  \
          XFS_SB_VERSION2_OKSASHFBITS )
 
-typedef struct xfs_sb
-{
+/*
+ * Superblock - in core version.  Must match the ondisk version below.
+ */
+typedef struct xfs_sb {
         __uint32_t      sb_magicnum;    /* magic number == XFS_SB_MAGIC */
         __uint32_t      sb_blocksize;   /* logical block size, bytes */
         xfs_drfsbno_t   sb_dblocks;     /* number of data blocks */
@@ -146,6 +148,66 @@ typedef struct xfs_sb
 } xfs_sb_t;
 
 /*
+ * Superblock - on disk version.  Must match the in core version below.
+ */
+typedef struct xfs_dsb {
+        __be32          sb_magicnum;    /* magic number == XFS_SB_MAGIC */
+        __be32          sb_blocksize;   /* logical block size, bytes */
+        __be64          sb_dblocks;     /* number of data blocks */
+        __be64          sb_rblocks;     /* number of realtime blocks */
+        __be64          sb_rextents;    /* number of realtime extents */
+        uuid_t          sb_uuid;        /* file system unique id */
+        __be64          sb_logstart;    /* starting block of log if internal */
+        __be64          sb_rootino;     /* root inode number */
+        __be64          sb_rbmino;      /* bitmap inode for realtime extents */
+        __be64          sb_rsumino;     /* summary inode for rt bitmap */
+        __be32          sb_rextsize;    /* realtime extent size, blocks */
+        __be32          sb_agblocks;    /* size of an allocation group */
+        __be32          sb_agcount;     /* number of allocation groups */
+        __be32          sb_rbmblocks;   /* number of rt bitmap blocks */
+        __be32          sb_logblocks;   /* number of log blocks */
+        __be16          sb_versionnum;  /* header version == XFS_SB_VERSION */
+        __be16          sb_sectsize;    /* volume sector size, bytes */
+        __be16          sb_inodesize;   /* inode size, bytes */
+        __be16          sb_inopblock;   /* inodes per block */
+        char            sb_fname[12];   /* file system name */
+        __u8            sb_blocklog;    /* log2 of sb_blocksize */
+        __u8            sb_sectlog;     /* log2 of sb_sectsize */
+        __u8            sb_inodelog;    /* log2 of sb_inodesize */
+        __u8            sb_inopblog;    /* log2 of sb_inopblock */
+        __u8            sb_agblklog;    /* log2 of sb_agblocks (rounded up) */
+        __u8            sb_rextslog;    /* log2 of sb_rextents */
+        __u8            sb_inprogress;  /* mkfs is in progress, don't mount */
+        __u8            sb_imax_pct;    /* max % of fs for inode space */
+                                        /* statistics */
+        /*
+         * These fields must remain contiguous.  If you really
+         * want to change their layout, make sure you fix the
+         * code in xfs_trans_apply_sb_deltas().
+         */
+        __be64          sb_icount;      /* allocated inodes */
+        __be64          sb_ifree;       /* free inodes */
+        __be64          sb_fdblocks;    /* free data blocks */
+        __be64          sb_frextents;   /* free realtime extents */
+        /*
+         * End contiguous fields.
+         */
+        __be64          sb_uquotino;    /* user quota inode */
+        __be64          sb_gquotino;    /* group quota inode */
+        __be16          sb_qflags;      /* quota flags */
+        __u8            sb_flags;       /* misc. flags */
+        __u8            sb_shared_vn;   /* shared version number */
+        __be32          sb_inoalignmt;  /* inode chunk alignment, fsblocks */
+        __be32          sb_unit;        /* stripe or raid unit */
+        __be32          sb_width;       /* stripe or raid width */
+        __u8            sb_dirblklog;   /* log2 of dir block size (fsbs) */
+        __u8            sb_logsectlog;  /* log2 of the log sector size */
+        __be16          sb_logsectsize; /* sector size for the log, bytes */
+        __be32          sb_logsunit;    /* stripe unit size for the log */
+        __be32          sb_features2;   /* additional feature bits */
+} xfs_dsb_t;
+
+/*
  * Sequence number values for the fields.
  */
 typedef enum {
@@ -446,7 +508,7 @@ static inline void xfs_sb_version_addattr2(xfs_sb_t *sbp)
 
 #define XFS_SB_DADDR            ((xfs_daddr_t)0) /* daddr in filesystem/ag */
 #define XFS_SB_BLOCK(mp)        XFS_HDR_BLOCK(mp, XFS_SB_DADDR)
-#define XFS_BUF_TO_SBP(bp)      ((xfs_sb_t *)XFS_BUF_PTR(bp))
+#define XFS_BUF_TO_SBP(bp)      ((xfs_dsb_t *)XFS_BUF_PTR(bp))
 
 #define XFS_HDR_BLOCK(mp,d)     ((xfs_agblock_t)XFS_BB_TO_FSBT(mp,d))
 #define XFS_DADDR_TO_FSB(mp,d)  XFS_AGB_TO_FSB(mp, \