Optimize e2fsck pass 1 by marking entire extents as being in use at a
time, instead of block by block. This optimization only works for
non-bigalloc file systems for now (it's tricky to handle bigalloc file
systems since this code is also responsible for dealing with blocks
that are not correctly aligned within a cluster). When the
optimization works, the CPU savings can be significant: up to two or
three CPU minutes for a full 4T disk.
Addresses-Google-Bug: #7534813
Signed-off-by: "Theodore Ts'o" <tytso@xxxxxxx>
---
e2fsck/pass1.c | 18 ++++++++++++++++--
1 file changed, 16 insertions(+), 2 deletions(-)
diff --git a/e2fsck/pass1.c b/e2fsck/pass1.c
index 78fbe8d..cc00e0f 100644
--- a/e2fsck/pass1.c
+++ b/e2fsck/pass1.c
@@ -1432,6 +1432,16 @@ static _INLINE_ void mark_block_used(e2fsck_t ctx, blk64_t block)
}
}
+static _INLINE_ void mark_blocks_used(e2fsck_t ctx, blk64_t block,
+ unsigned int num)
+{
+ if (ext2fs_test_block_bitmap_range2(ctx->block_found_map, block, num))
+ ext2fs_mark_block_bitmap_range2(ctx->block_found_map, block, num);
+ else
+ while (num--)
+ mark_block_used(ctx, block++);
+}
+
/*
* Adjust the extended attribute block's reference counts at the end
* of pass 1, either by subtracting out references for EA blocks that
@@ -1867,11 +1877,15 @@ static void scan_extent_node(e2fsck_t ctx, struct problem_context *pctx,
goto failed_add_dir_block;
}
}
+ if (!ctx->fs->cluster_ratio_bits) {
+ mark_blocks_used(ctx, extent.e_pblk, extent.e_len);
+ pb->num_blocks += extent.e_len;
+ }
for (blk = extent.e_pblk, blockcnt = extent.e_lblk, i = 0;
i < extent.e_len;
blk++, blockcnt++, i++) {
- if (!(ctx->fs->cluster_ratio_bits &&
- pb->previous_block &&
+ if (ctx->fs->cluster_ratio_bits &&
+ !(pb->previous_block &&
(EXT2FS_B2C(ctx->fs, blk) ==
EXT2FS_B2C(ctx->fs, pb->previous_block)) &&
(blk & EXT2FS_CLUSTER_MASK(ctx->fs)) ==
--
1.7.12.rc0.22.gcdd159b
--
To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
