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authorDave Chinner <dchinner@redhat.com>2012-06-22 18:50:07 +1000
committerBen Myers <bpm@sgi.com>2012-07-01 14:50:04 -0500
commit77c1a08fc9ece4cb130b9fd279738e799f0c2864 (patch)
tree1f22efa502d7bfbd7a38a238cd1a09730548cba7 /fs/xfs/xfs_buf_item.h
parent9a8d2fdbb47aaa1eaa136b89da5e5e6b60015c78 (diff)
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xfs: struct xfs_buf_log_format isn't variable sized.
The struct xfs_buf_log_format wants to think the dirty bitmap is variable sized. In fact, it is variable size on disk simply due to the way we map it from the in-memory structure, but we still just use a fixed size memory allocation for the in-memory structure. Hence it makes no sense to set the function up as a variable sized structure when we already know it's maximum size, and we always allocate it as such. Simplify the structure by making the dirty bitmap a fixed sized array and just using the size of the structure for the allocation size. This will make it much simpler to allocate and manipulate an array of format structures for discontiguous buffer support. The previous struct xfs_buf_log_item size according to /proc/slabinfo was 224 bytes. pahole doesn't give the same size because of the variable size definition. With this modification, pahole reports the same as /proc/slabinfo: /* size: 224, cachelines: 4, members: 6 */ Because the xfs_buf_log_item size is now determined by the maximum supported block size we introduce a dependency on xfs_alloc_btree.h. Avoid this dependency by moving the idefines for the maximum block sizes supported to xfs_types.h with all the other max/min type defines to avoid any new dependencies. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Ben Myers <bpm@sgi.com>
Diffstat (limited to 'fs/xfs/xfs_buf_item.h')
-rw-r--r--fs/xfs/xfs_buf_item.h36
1 files changed, 18 insertions, 18 deletions
diff --git a/fs/xfs/xfs_buf_item.h b/fs/xfs/xfs_buf_item.h
index b6ecd2061e7c..ff2686780239 100644
--- a/fs/xfs/xfs_buf_item.h
+++ b/fs/xfs/xfs_buf_item.h
@@ -21,23 +21,6 @@
extern kmem_zone_t *xfs_buf_item_zone;
/*
- * This is the structure used to lay out a buf log item in the
- * log. The data map describes which 128 byte chunks of the buffer
- * have been logged.
- * For 6.2 and beyond, this is XFS_LI_BUF. We use this to log everything.
- */
-typedef struct xfs_buf_log_format {
- unsigned short blf_type; /* buf log item type indicator */
- unsigned short blf_size; /* size of this item */
- ushort blf_flags; /* misc state */
- ushort blf_len; /* number of blocks in this buf */
- __int64_t blf_blkno; /* starting blkno of this buf */
- unsigned int blf_map_size; /* size of data bitmap in words */
- unsigned int blf_data_map[1];/* variable size bitmap of */
- /* regions of buffer in this item */
-} xfs_buf_log_format_t;
-
-/*
* This flag indicates that the buffer contains on disk inodes
* and requires special recovery handling.
*/
@@ -61,6 +44,23 @@ typedef struct xfs_buf_log_format {
#define NBWORD (NBBY * sizeof(unsigned int))
/*
+ * This is the structure used to lay out a buf log item in the
+ * log. The data map describes which 128 byte chunks of the buffer
+ * have been logged.
+ */
+#define XFS_BLF_DATAMAP_SIZE ((XFS_MAX_BLOCKSIZE / XFS_BLF_CHUNK) / NBWORD)
+
+typedef struct xfs_buf_log_format {
+ unsigned short blf_type; /* buf log item type indicator */
+ unsigned short blf_size; /* size of this item */
+ ushort blf_flags; /* misc state */
+ ushort blf_len; /* number of blocks in this buf */
+ __int64_t blf_blkno; /* starting blkno of this buf */
+ unsigned int blf_map_size; /* used size of data bitmap in words */
+ unsigned int blf_data_map[XFS_BLF_DATAMAP_SIZE]; /* dirty bitmap */
+} xfs_buf_log_format_t;
+
+/*
* buf log item flags
*/
#define XFS_BLI_HOLD 0x01
@@ -102,7 +102,7 @@ typedef struct xfs_buf_log_item {
char *bli_orig; /* original buffer copy */
char *bli_logged; /* bytes logged (bitmap) */
#endif
- xfs_buf_log_format_t bli_format; /* in-log header */
+ struct xfs_buf_log_format bli_format; /* embedded in-log header */
} xfs_buf_log_item_t;
void xfs_buf_item_init(struct xfs_buf *, struct xfs_mount *);