[PATCH 1/8] btrfs: scrub: distinguish scrub_page from regular page

[Qu Wenruo <wqu@suse.com>]

There are several call sites where we declare something like
"struct scrub_page *page".

This is just asking for troubles when read the code, as we also have
scrub_page::page member.

To avoid confusion, use "spage" for scrub_page strcture pointers.

Signed-off-by: Qu Wenruo <wqu@suse.com>
---
 fs/btrfs/scrub.c | 102 +++++++++++++++++++++++------------------------
 1 file changed, 51 insertions(+), 51 deletions(-)

diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index 806523515d2f..0e25f9391b93 100644
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -256,10 +256,10 @@ static void __scrub_blocked_if_needed(struct btrfs_fs_info *fs_info);
 static void scrub_blocked_if_needed(struct btrfs_fs_info *fs_info);
 static void scrub_put_ctx(struct scrub_ctx *sctx);
 
-static inline int scrub_is_page_on_raid56(struct scrub_page *page)
+static inline int scrub_is_page_on_raid56(struct scrub_page *spage)
 {
-	return page->recover &&
-	       (page->recover->bbio->map_type & BTRFS_BLOCK_GROUP_RAID56_MASK);
+	return spage->recover &&
+	       (spage->recover->bbio->map_type & BTRFS_BLOCK_GROUP_RAID56_MASK);
 }
 
 static void scrub_pending_bio_inc(struct scrub_ctx *sctx)
@@ -1092,11 +1092,11 @@ static int scrub_handle_errored_block(struct scrub_block *sblock_to_check)
 	success = 1;
 	for (page_num = 0; page_num < sblock_bad->page_count;
 	     page_num++) {
-		struct scrub_page *page_bad = sblock_bad->pagev[page_num];
+		struct scrub_page *spage_bad = sblock_bad->pagev[page_num];
 		struct scrub_block *sblock_other = NULL;
 
 		/* skip no-io-error page in scrub */
-		if (!page_bad->io_error && !sctx->is_dev_replace)
+		if (!spage_bad->io_error && !sctx->is_dev_replace)
 			continue;
 
 		if (scrub_is_page_on_raid56(sblock_bad->pagev[0])) {
@@ -1108,7 +1108,7 @@ static int scrub_handle_errored_block(struct scrub_block *sblock_to_check)
 			 * sblock_for_recheck array to target device.
 			 */
 			sblock_other = NULL;
-		} else if (page_bad->io_error) {
+		} else if (spage_bad->io_error) {
 			/* try to find no-io-error page in mirrors */
 			for (mirror_index = 0;
 			     mirror_index < BTRFS_MAX_MIRRORS &&
@@ -1147,7 +1147,7 @@ static int scrub_handle_errored_block(struct scrub_block *sblock_to_check)
 							       sblock_other,
 							       page_num, 0);
 			if (0 == ret)
-				page_bad->io_error = 0;
+				spage_bad->io_error = 0;
 			else
 				success = 0;
 		}
@@ -1325,13 +1325,13 @@ static int scrub_setup_recheck_block(struct scrub_block *original_sblock,
 		for (mirror_index = 0; mirror_index < nmirrors;
 		     mirror_index++) {
 			struct scrub_block *sblock;
-			struct scrub_page *page;
+			struct scrub_page *spage;
 
 			sblock = sblocks_for_recheck + mirror_index;
 			sblock->sctx = sctx;
 
-			page = kzalloc(sizeof(*page), GFP_NOFS);
-			if (!page) {
+			spage = kzalloc(sizeof(*spage), GFP_NOFS);
+			if (!spage) {
 leave_nomem:
 				spin_lock(&sctx->stat_lock);
 				sctx->stat.malloc_errors++;
@@ -1339,15 +1339,15 @@ static int scrub_setup_recheck_block(struct scrub_block *original_sblock,
 				scrub_put_recover(fs_info, recover);
 				return -ENOMEM;
 			}
-			scrub_page_get(page);
-			sblock->pagev[page_index] = page;
-			page->sblock = sblock;
-			page->flags = flags;
-			page->generation = generation;
-			page->logical = logical;
-			page->have_csum = have_csum;
+			scrub_page_get(spage);
+			sblock->pagev[page_index] = spage;
+			spage->sblock = sblock;
+			spage->flags = flags;
+			spage->generation = generation;
+			spage->logical = logical;
+			spage->have_csum = have_csum;
 			if (have_csum)
-				memcpy(page->csum,
+				memcpy(spage->csum,
 				       original_sblock->pagev[0]->csum,
 				       sctx->csum_size);
 
@@ -1360,23 +1360,23 @@ static int scrub_setup_recheck_block(struct scrub_block *original_sblock,
 						      mirror_index,
 						      &stripe_index,
 						      &stripe_offset);
-			page->physical = bbio->stripes[stripe_index].physical +
+			spage->physical = bbio->stripes[stripe_index].physical +
 					 stripe_offset;
-			page->dev = bbio->stripes[stripe_index].dev;
+			spage->dev = bbio->stripes[stripe_index].dev;
 
 			BUG_ON(page_index >= original_sblock->page_count);
-			page->physical_for_dev_replace =
+			spage->physical_for_dev_replace =
 				original_sblock->pagev[page_index]->
 				physical_for_dev_replace;
 			/* for missing devices, dev->bdev is NULL */
-			page->mirror_num = mirror_index + 1;
+			spage->mirror_num = mirror_index + 1;
 			sblock->page_count++;
-			page->page = alloc_page(GFP_NOFS);
-			if (!page->page)
+			spage->page = alloc_page(GFP_NOFS);
+			if (!spage->page)
 				goto leave_nomem;
 
 			scrub_get_recover(recover);
-			page->recover = recover;
+			spage->recover = recover;
 		}
 		scrub_put_recover(fs_info, recover);
 		length -= sublen;
@@ -1394,19 +1394,19 @@ static void scrub_bio_wait_endio(struct bio *bio)
 
 static int scrub_submit_raid56_bio_wait(struct btrfs_fs_info *fs_info,
 					struct bio *bio,
-					struct scrub_page *page)
+					struct scrub_page *spage)
 {
 	DECLARE_COMPLETION_ONSTACK(done);
 	int ret;
 	int mirror_num;
 
-	bio->bi_iter.bi_sector = page->logical >> 9;
+	bio->bi_iter.bi_sector = spage->logical >> 9;
 	bio->bi_private = &done;
 	bio->bi_end_io = scrub_bio_wait_endio;
 
-	mirror_num = page->sblock->pagev[0]->mirror_num;
-	ret = raid56_parity_recover(fs_info, bio, page->recover->bbio,
-				    page->recover->map_length,
+	mirror_num = spage->sblock->pagev[0]->mirror_num;
+	ret = raid56_parity_recover(fs_info, bio, spage->recover->bbio,
+				    spage->recover->map_length,
 				    mirror_num, 0);
 	if (ret)
 		return ret;
@@ -1431,10 +1431,10 @@ static void scrub_recheck_block_on_raid56(struct btrfs_fs_info *fs_info,
 	bio_set_dev(bio, first_page->dev->bdev);
 
 	for (page_num = 0; page_num < sblock->page_count; page_num++) {
-		struct scrub_page *page = sblock->pagev[page_num];
+		struct scrub_page *spage = sblock->pagev[page_num];
 
-		WARN_ON(!page->page);
-		bio_add_page(bio, page->page, PAGE_SIZE, 0);
+		WARN_ON(!spage->page);
+		bio_add_page(bio, spage->page, PAGE_SIZE, 0);
 	}
 
 	if (scrub_submit_raid56_bio_wait(fs_info, bio, first_page)) {
@@ -1475,24 +1475,24 @@ static void scrub_recheck_block(struct btrfs_fs_info *fs_info,
 
 	for (page_num = 0; page_num < sblock->page_count; page_num++) {
 		struct bio *bio;
-		struct scrub_page *page = sblock->pagev[page_num];
+		struct scrub_page *spage = sblock->pagev[page_num];
 
-		if (page->dev->bdev == NULL) {
-			page->io_error = 1;
+		if (spage->dev->bdev == NULL) {
+			spage->io_error = 1;
 			sblock->no_io_error_seen = 0;
 			continue;
 		}
 
-		WARN_ON(!page->page);
+		WARN_ON(!spage->page);
 		bio = btrfs_io_bio_alloc(1);
-		bio_set_dev(bio, page->dev->bdev);
+		bio_set_dev(bio, spage->dev->bdev);
 
-		bio_add_page(bio, page->page, PAGE_SIZE, 0);
-		bio->bi_iter.bi_sector = page->physical >> 9;
+		bio_add_page(bio, spage->page, PAGE_SIZE, 0);
+		bio->bi_iter.bi_sector = spage->physical >> 9;
 		bio->bi_opf = REQ_OP_READ;
 
 		if (btrfsic_submit_bio_wait(bio)) {
-			page->io_error = 1;
+			spage->io_error = 1;
 			sblock->no_io_error_seen = 0;
 		}
 
@@ -1548,36 +1548,36 @@ static int scrub_repair_page_from_good_copy(struct scrub_block *sblock_bad,
 					    struct scrub_block *sblock_good,
 					    int page_num, int force_write)
 {
-	struct scrub_page *page_bad = sblock_bad->pagev[page_num];
-	struct scrub_page *page_good = sblock_good->pagev[page_num];
+	struct scrub_page *spage_bad = sblock_bad->pagev[page_num];
+	struct scrub_page *spage_good = sblock_good->pagev[page_num];
 	struct btrfs_fs_info *fs_info = sblock_bad->sctx->fs_info;
 
-	BUG_ON(page_bad->page == NULL);
-	BUG_ON(page_good->page == NULL);
+	BUG_ON(spage_bad->page == NULL);
+	BUG_ON(spage_good->page == NULL);
 	if (force_write || sblock_bad->header_error ||
-	    sblock_bad->checksum_error || page_bad->io_error) {
+	    sblock_bad->checksum_error || spage_bad->io_error) {
 		struct bio *bio;
 		int ret;
 
-		if (!page_bad->dev->bdev) {
+		if (!spage_bad->dev->bdev) {
 			btrfs_warn_rl(fs_info,
 				"scrub_repair_page_from_good_copy(bdev == NULL) is unexpected");
 			return -EIO;
 		}
 
 		bio = btrfs_io_bio_alloc(1);
-		bio_set_dev(bio, page_bad->dev->bdev);
-		bio->bi_iter.bi_sector = page_bad->physical >> 9;
+		bio_set_dev(bio, spage_bad->dev->bdev);
+		bio->bi_iter.bi_sector = spage_bad->physical >> 9;
 		bio->bi_opf = REQ_OP_WRITE;
 
-		ret = bio_add_page(bio, page_good->page, PAGE_SIZE, 0);
+		ret = bio_add_page(bio, spage_good->page, PAGE_SIZE, 0);
 		if (PAGE_SIZE != ret) {
 			bio_put(bio);
 			return -EIO;
 		}
 
 		if (btrfsic_submit_bio_wait(bio)) {
-			btrfs_dev_stat_inc_and_print(page_bad->dev,
+			btrfs_dev_stat_inc_and_print(spage_bad->dev,
 				BTRFS_DEV_STAT_WRITE_ERRS);
 			atomic64_inc(&fs_info->dev_replace.num_write_errors);
 			bio_put(bio);
-- 
2.29.0