xfs: read leaf blocks when computing keys for bulkloading into node blocks

When constructing a new btree, xfs_btree_bload_node needs to read the
btree blocks for level N to compute the keyptrs for the blocks that will
be loaded into level N+1.  The level N blocks must be formatted at that
point.

A subsequent patch will change the btree bulkloader to write new btree
blocks in 256K chunks to moderate memory consumption if the new btree is
very large.  As a consequence of that, it's possible that the buffers
for lower level blocks might have been reclaimed by the time the node
builder comes back to the block.

Therefore, change xfs_btree_bload_node to read the lower level blocks
to handle the reclaimed buffer case.  As a side effect, the read will
increase the LRU refs, which will bias towards keeping new btree buffers
in memory after the new btree commits.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

diff --git a/fs/xfs/libxfs/xfs_btree.c b/fs/xfs/libxfs/xfs_btree.c
index 6a6503ab0cd76e7bae2c396e1438a23698f69e9c..c100e92140be141501302861a46afc2532d19c4b 100644 (file)
--- a/fs/xfs/libxfs/xfs_btree.c
+++ b/fs/xfs/libxfs/xfs_btree.c
@@ -1330,7 +1330,7 @@ xfs_btree_get_buf_block(
  * Read in the buffer at the given ptr and return the buffer and
  * the block pointer within the buffer.
  */
-STATIC int
+int
 xfs_btree_read_buf_block(
        struct xfs_btree_cur            *cur,
        const union xfs_btree_ptr       *ptr,

diff --git a/fs/xfs/libxfs/xfs_btree.h b/fs/xfs/libxfs/xfs_btree.h
index 4d68a58be160cf86452d4fbb21eaf1b2de8fe6a3..e0875cec4939255cfd579032c3e8c71e58ea05d0 100644 (file)
--- a/fs/xfs/libxfs/xfs_btree.h
+++ b/fs/xfs/libxfs/xfs_btree.h
@@ -700,6 +700,9 @@ void xfs_btree_set_ptr_null(struct xfs_btree_cur *cur,
 int xfs_btree_get_buf_block(struct xfs_btree_cur *cur,
                const union xfs_btree_ptr *ptr, struct xfs_btree_block **block,
                struct xfs_buf **bpp);
+int xfs_btree_read_buf_block(struct xfs_btree_cur *cur,
+               const union xfs_btree_ptr *ptr, int flags,
+               struct xfs_btree_block **block, struct xfs_buf **bpp);
 void xfs_btree_set_sibling(struct xfs_btree_cur *cur,
                struct xfs_btree_block *block, const union xfs_btree_ptr *ptr,
                int lr);

diff --git a/fs/xfs/libxfs/xfs_btree_staging.c b/fs/xfs/libxfs/xfs_btree_staging.c
index 1c5f9ed70c3e074d85f8a2ac2ec2139d3fd3be2f..c8b46ac3923f800370b02960a693a5703edc7db5 100644 (file)
--- a/fs/xfs/libxfs/xfs_btree_staging.c
+++ b/fs/xfs/libxfs/xfs_btree_staging.c
@@ -489,7 +489,12 @@ xfs_btree_bload_node(
 
                ASSERT(!xfs_btree_ptr_is_null(cur, child_ptr));
 
-               ret = xfs_btree_get_buf_block(cur, child_ptr, &child_block,
+               /*
+                * Read the lower-level block in case the buffer for it has
+                * been reclaimed.  LRU refs will be set on the block, which is
+                * desirable if the new btree commits.
+                */
+               ret = xfs_btree_read_buf_block(cur, child_ptr, 0, &child_block,
                                &child_bp);
                if (ret)
                        return ret;