[XFS] 929045 567344 This mod introduces multi-level in-core file extent
functionality, building upon the new layout introduced in mod
xfs-linux:xfs-kern:207390a. The new multi-level extent allocations are
only required for heavily fragmented files, so the old-style linear extent
list is used on files until the extents reach a pre-determined size of 4k.
4k buffers are used because this 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. The 4k extent buffers are managed by an indirection
array (xfs_ext_irec_t) which is basically just a pointer array with a bit
of extra information to keep track of the number of extents in each buffer
as well as the extent offset of each buffer. Major changes include: -
Add multi-level in-core file extent functionality to the xfs_iext_
subroutines introduced in mod: xfs-linux:xfs-kern:207390a - Introduce 13
new subroutines which add functionality for multi-level in-core file
extents: xfs_iext_add_indirect_multi()
xfs_iext_remove_indirect() xfs_iext_realloc_indirect()
xfs_iext_indirect_to_direct() xfs_iext_bno_to_irec()
xfs_iext_idx_to_irec() xfs_iext_irec_init()
xfs_iext_irec_new() xfs_iext_irec_remove()
xfs_iext_irec_compact() xfs_iext_irec_compact_pages()
xfs_iext_irec_compact_full() xfs_iext_irec_update_extoffs()
SGI-PV: 928864
SGI-Modid: xfs-linux-melb:xfs-kern:207393a
Signed-off-by: Mandy Kirkconnell <alkirkco@sgi.com>
Signed-off-by: Nathan Scott <nathans@sgi.com>
diff --git a/fs/xfs/xfs_inode.h b/fs/xfs/xfs_inode.h
index 740b73f..3c1df1d6 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 @@
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 @@
/*
* 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 @@
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))