While doing recovery, blocks are read from the raid5/6 disk one by
one, so this is adding readahead so that we can read at most 256
contiguous blocks in one read IO.
Signed-off-by: Liu Bo <bo.li....@oracle.com>
---
fs/btrfs/raid56.c | 114 +++++++++++++++++++++++++++++++++++++++++++++++++++---
1 file changed, 109 insertions(+), 5 deletions(-)
diff --git a/fs/btrfs/raid56.c b/fs/btrfs/raid56.c
index dea33c4..24f7cbb 100644
--- a/fs/btrfs/raid56.c
+++ b/fs/btrfs/raid56.c
@@ -1530,15 +1530,81 @@ static int btrfs_r5l_write_empty_meta_block(struct
btrfs_r5l_log *log, u64 pos,
return ret;
}
+#define BTRFS_R5L_RECOVER_IO_POOL_SIZE BIO_MAX_PAGES
struct btrfs_r5l_recover_ctx {
u64 pos;
u64 seq;
u64 total_size;
struct page *meta_page;
struct page *io_page;
+
+ struct page *ra_pages[BTRFS_R5L_RECOVER_IO_POOL_SIZE];
+ struct bio *ra_bio;
+ int total;
+ int valid;
+ u64 start_offset;
+
+ struct btrfs_r5l_log *log;
};
-static int btrfs_r5l_recover_load_meta(struct btrfs_r5l_log *log, struct
btrfs_r5l_recover_ctx *ctx)
+static int btrfs_r5l_recover_read_ra(struct btrfs_r5l_recover_ctx *ctx, u64
offset)
+{
+ bio_reset(ctx->ra_bio);
+ ctx->ra_bio->bi_bdev = ctx->log->dev->bdev;
+ ctx->ra_bio->bi_opf = REQ_OP_READ;
+ ctx->ra_bio->bi_iter.bi_sector = (ctx->log->data_offset + offset) >> 9;
+
+ ctx->valid = 0;
+ ctx->start_offset = offset;
+
+ while (ctx->valid < ctx->total) {
+ bio_add_page(ctx->ra_bio, ctx->ra_pages[ctx->valid++],
PAGE_SIZE, 0);
+
+ offset = btrfs_r5l_ring_add(ctx->log, offset, PAGE_SIZE);
+ if (offset == 0)
+ break;
+ }
+
+#ifdef BTRFS_DEBUG_R5LOG
+ trace_printk("to read %d pages starting from 0x%llx\n", ctx->valid,
ctx->log->data_offset + ctx->start_offset);
+#endif
+ return submit_bio_wait(ctx->ra_bio);
+}
+
+static int btrfs_r5l_recover_read_page(struct btrfs_r5l_recover_ctx *ctx,
struct page *page, u64 offset)
+{
+ struct page *tmp;
+ int index;
+ char *src;
+ char *dst;
+ int ret;
+
+ if (offset < ctx->start_offset || offset >= (ctx->start_offset +
ctx->valid * PAGE_SIZE)) {
+ ret = btrfs_r5l_recover_read_ra(ctx, offset);
+ if (ret)
+ return ret;
+ }
+
+#ifdef BTRFS_DEBUG_R5LOG
+ trace_printk("offset 0x%llx start->offset 0x%llx ctx->valid %d\n",
offset, ctx->start_offset, ctx->valid);
+#endif
+
+ ASSERT(IS_ALIGNED(ctx->start_offset, PAGE_SIZE));
+ ASSERT(IS_ALIGNED(offset, PAGE_SIZE));
+
+ index = (offset - ctx->start_offset) >> PAGE_SHIFT;
+ ASSERT(index < ctx->valid);
+
+ tmp = ctx->ra_pages[index];
+ src = kmap(tmp);
+ dst = kmap(page);
+ memcpy(dst, src, PAGE_SIZE);
+ kunmap(page);
+ kunmap(tmp);
+ return 0;
+}
+
+static int btrfs_r5l_recover_load_meta(struct btrfs_r5l_recover_ctx *ctx)
{
struct btrfs_r5l_meta_block *mb;
@@ -1642,6 +1708,42 @@ static int btrfs_r5l_recover_flush_log(struct
btrfs_r5l_log *log, struct btrfs_r
}
return ret;
+
+static int btrfs_r5l_recover_allocate_ra(struct btrfs_r5l_recover_ctx *ctx)
+{
+ struct page *page;
+ ctx->ra_bio = btrfs_io_bio_alloc(GFP_NOFS, BIO_MAX_PAGES);
+
+ ctx->total = 0;
+ ctx->valid = 0;
+ while (ctx->total < BTRFS_R5L_RECOVER_IO_POOL_SIZE) {
+ page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
+ if (!page)
+ break;
+
+ ctx->ra_pages[ctx->total++] = page;
+ }
+
+ if (ctx->total == 0) {
+ bio_put(ctx->ra_bio);
+ return -ENOMEM;
+ }
+
+#ifdef BTRFS_DEBUG_R5LOG
+ trace_printk("readahead: %d allocated pages\n", ctx->total);
+#endif
+ return 0;
+}
+
+static void btrfs_r5l_recover_free_ra(struct btrfs_r5l_recover_ctx *ctx)
+{
+ int i;
+#ifdef BTRFS_DEBUG_R5LOG
+ trace_printk("readahead: %d to free pages\n", ctx->total);
+#endif
+ for (i = 0; i < ctx->total; i++)
+ __free_page(ctx->ra_pages[i]);
+ bio_put(ctx->ra_bio);
}
static void btrfs_r5l_write_super(struct btrfs_fs_info *fs_info, u64 cp);
@@ -1655,6 +1757,7 @@ static int btrfs_r5l_recover_log(struct btrfs_r5l_log
*log)
ctx = kzalloc(sizeof(*ctx), GFP_NOFS);
ASSERT(ctx);
+ ctx->log = log;
ctx->pos = log->last_checkpoint;
ctx->seq = log->last_cp_seq;
ctx->meta_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
@@ -1662,10 +1765,10 @@ static int btrfs_r5l_recover_log(struct btrfs_r5l_log
*log)
ctx->io_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
ASSERT(ctx->io_page);
- ret = btrfs_r5l_recover_flush_log(log, ctx);
- if (ret) {
- ;
- }
+ ret = btrfs_r5l_recover_allocate_ra(ctx);
+ ASSERT(ret == 0);
+
+ btrfs_r5l_recover_flush_log(ctx);
pos = ctx->pos;
log->next_checkpoint = ctx->pos;
@@ -1684,6 +1787,7 @@ static int btrfs_r5l_recover_log(struct btrfs_r5l_log
*log)
#endif
__free_page(ctx->meta_page);
__free_page(ctx->io_page);
+ btrfs_r5l_recover_free_ra(ctx);
kfree(ctx);
return 0;
}
--
2.9.4
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