1 files changed, 47 insertions, 5 deletions

diff --git a/fs/xfs/xfs_inode.h b/fs/xfs/xfs_inode.h
index 740b73fabd2f..3c1df1d642fa 100644
--- a/fs/xfs/xfs_inode.h
+++ b/fs/xfs/xfs_inode.h
@@ -25,10 +25,37 @@
 #define XFS_ATTR_FORK   1
 
 /*
+ * The following xfs_ext_irec_t struct introduces a second (top) level
+ * to the in-core extent allocation scheme. These structs are allocated
+ * in a contiguous block, creating an indirection array where each entry
+ * (irec) contains a pointer to a buffer of in-core extent records which
+ * it manages. Each extent buffer is 4k in size, since 4k is the system
+ * page size on Linux i386 and systems with larger page sizes don't seem
+ * to gain much, if anything, by using their native page size as the
+ * extent buffer size. Also, using 4k extent buffers everywhere provides
+ * a consistent interface for CXFS across different platforms.
+ *
+ * There is currently no limit on the number of irec's (extent lists)
+ * allowed, so heavily fragmented files may require an indirection array
+ * which spans multiple system pages of memory. The number of extents
+ * which would require this amount of contiguous memory is very large
+ * and should not cause problems in the foreseeable future. However,
+ * if the memory needed for the contiguous array ever becomes a problem,
+ * it is possible that a third level of indirection may be required.
+ */
+typedef struct xfs_ext_irec {
+        xfs_bmbt_rec_t  *er_extbuf;     /* block of extent records */
+        xfs_extnum_t    er_extoff;      /* extent offset in file */
+        xfs_extnum_t    er_extcount;    /* number of extents in page/block */
+} xfs_ext_irec_t;
+
+/*
  * File incore extent information, present for each of data & attr forks.
  */
-#define XFS_INLINE_EXTS 2
-#define XFS_INLINE_DATA 32
+#define XFS_IEXT_BUFSZ          4096
+#define XFS_LINEAR_EXTS         (XFS_IEXT_BUFSZ / (uint)sizeof(xfs_bmbt_rec_t))
+#define XFS_INLINE_EXTS         2
+#define XFS_INLINE_DATA         32
 typedef struct xfs_ifork {
         int                     if_bytes;       /* bytes in if_u1 */
         int                     if_real_bytes;  /* bytes allocated in if_u1 */
@@ -39,6 +66,7 @@ typedef struct xfs_ifork {
         xfs_extnum_t            if_lastex;      /* last if_extents used */
         union {
                 xfs_bmbt_rec_t  *if_extents;    /* linear map file exts */
+                xfs_ext_irec_t  *if_ext_irec;   /* irec map file exts */
                 char            *if_data;       /* inline file data */
         } if_u1;
         union {
@@ -61,9 +89,10 @@ typedef struct xfs_ifork {
 /*
  * Per-fork incore inode flags.
  */
-#define XFS_IFINLINE    0x0001  /* Inline data is read in */
-#define XFS_IFEXTENTS   0x0002  /* All extent pointers are read in */
-#define XFS_IFBROOT     0x0004  /* i_broot points to the bmap b-tree root */
+#define XFS_IFINLINE    0x01    /* Inline data is read in */
+#define XFS_IFEXTENTS   0x02    /* All extent pointers are read in */
+#define XFS_IFBROOT     0x04    /* i_broot points to the bmap b-tree root */
+#define XFS_IFEXTIREC   0x08    /* Indirection array of extent blocks */
 
 /*
  * Flags for xfs_imap() and xfs_dilocate().
@@ -438,13 +467,26 @@ xfs_bmbt_rec_t	*xfs_iext_get_ext(xfs_ifork_t *, xfs_extnum_t);
 void            xfs_iext_insert(xfs_ifork_t *, xfs_extnum_t, xfs_extnum_t,
                                 xfs_bmbt_irec_t *);
 void            xfs_iext_add(xfs_ifork_t *, xfs_extnum_t, int);
+void            xfs_iext_add_indirect_multi(xfs_ifork_t *, int, xfs_extnum_t, int);
 void            xfs_iext_remove(xfs_ifork_t *, xfs_extnum_t, int);
 void            xfs_iext_remove_inline(xfs_ifork_t *, xfs_extnum_t, int);
 void            xfs_iext_remove_direct(xfs_ifork_t *, xfs_extnum_t, int);
+void            xfs_iext_remove_indirect(xfs_ifork_t *, xfs_extnum_t, int);
 void            xfs_iext_realloc_direct(xfs_ifork_t *, int);
+void            xfs_iext_realloc_indirect(xfs_ifork_t *, int);
+void            xfs_iext_indirect_to_direct(xfs_ifork_t *);
 void            xfs_iext_direct_to_inline(xfs_ifork_t *, xfs_extnum_t);
 void            xfs_iext_inline_to_direct(xfs_ifork_t *, int);
 void            xfs_iext_destroy(xfs_ifork_t *);
+xfs_ext_irec_t  *xfs_iext_bno_to_irec(xfs_ifork_t *, xfs_fileoff_t, int *);
+xfs_ext_irec_t  *xfs_iext_idx_to_irec(xfs_ifork_t *, xfs_extnum_t *, int *, int);
+void            xfs_iext_irec_init(xfs_ifork_t *);
+xfs_ext_irec_t *xfs_iext_irec_new(xfs_ifork_t *, int);
+void            xfs_iext_irec_remove(xfs_ifork_t *, int);
+void            xfs_iext_irec_compact(xfs_ifork_t *);
+void            xfs_iext_irec_compact_pages(xfs_ifork_t *);
+void            xfs_iext_irec_compact_full(xfs_ifork_t *);
+void            xfs_iext_irec_update_extoffs(xfs_ifork_t *, int, int);
 
 #define xfs_ipincount(ip)       ((unsigned int) atomic_read(&ip->i_pincount))