1 files changed, 52 insertions, 38 deletions

diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index 79bd479317cb..4ba2a69a60ad 100644
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -2126,8 +2126,7 @@ static int scrub_find_csum(struct scrub_ctx *sctx, u64 logical, u64 len,
                            u8 *csum)
 {
         struct btrfs_ordered_sum *sum = NULL;
-        int ret = 0;
-        unsigned long i;
+        unsigned long index;
         unsigned long num_sectors;
 
         while (!list_empty(&sctx->csum_list)) {
@@ -2146,19 +2145,14 @@ static int scrub_find_csum(struct scrub_ctx *sctx, u64 logical, u64 len,
         if (!sum)
                 return 0;
 
+        index = ((u32)(logical - sum->bytenr)) / sctx->sectorsize;
         num_sectors = sum->len / sctx->sectorsize;
-        for (i = 0; i < num_sectors; ++i) {
-                if (sum->sums[i].bytenr == logical) {
-                        memcpy(csum, &sum->sums[i].sum, sctx->csum_size);
-                        ret = 1;
-                        break;
-                }
-        }
-        if (ret && i == num_sectors - 1) {
+        memcpy(csum, sum->sums + index, sctx->csum_size);
+        if (index == num_sectors - 1) {
                 list_del(&sum->list);
                 kfree(sum);
         }
-        return ret;
+        return 1;
 }
 
 /* scrub extent tries to collect up to 64 kB for each bio */
@@ -2505,6 +2499,7 @@ again:
                         if (ret)
                                 goto out;
 
+                        scrub_free_csums(sctx);
                         if (extent_logical + extent_len <
                             key.objectid + bytes) {
                                 logical += increment;
@@ -3204,16 +3199,18 @@ out:
 
 static int copy_nocow_pages_for_inode(u64 inum, u64 offset, u64 root, void *ctx)
 {
-        unsigned long index;
         struct scrub_copy_nocow_ctx *nocow_ctx = ctx;
-        int ret = 0;
+        struct btrfs_fs_info *fs_info = nocow_ctx->sctx->dev_root->fs_info;
         struct btrfs_key key;
-        struct inode *inode = NULL;
+        struct inode *inode;
+        struct page *page;
         struct btrfs_root *local_root;
         u64 physical_for_dev_replace;
         u64 len;
-        struct btrfs_fs_info *fs_info = nocow_ctx->sctx->dev_root->fs_info;
+        unsigned long index;
         int srcu_index;
+        int ret;
+        int err;
 
         key.objectid = root;
         key.type = BTRFS_ROOT_ITEM_KEY;
@@ -3227,6 +3224,11 @@ static int copy_nocow_pages_for_inode(u64 inum, u64 offset, u64 root, void *ctx)
                 return PTR_ERR(local_root);
         }
 
+        if (btrfs_root_refs(&local_root->root_item) == 0) {
+                srcu_read_unlock(&fs_info->subvol_srcu, srcu_index);
+                return -ENOENT;
+        }
+
         key.type = BTRFS_INODE_ITEM_KEY;
         key.objectid = inum;
         key.offset = 0;
@@ -3235,19 +3237,21 @@ static int copy_nocow_pages_for_inode(u64 inum, u64 offset, u64 root, void *ctx)
         if (IS_ERR(inode))
                 return PTR_ERR(inode);
 
+        /* Avoid truncate/dio/punch hole.. */
+        mutex_lock(&inode->i_mutex);
+        inode_dio_wait(inode);
+
+        ret = 0;
         physical_for_dev_replace = nocow_ctx->physical_for_dev_replace;
         len = nocow_ctx->len;
         while (len >= PAGE_CACHE_SIZE) {
-                struct page *page = NULL;
-                int ret_sub;
-
                 index = offset >> PAGE_CACHE_SHIFT;
-
+again:
                 page = find_or_create_page(inode->i_mapping, index, GFP_NOFS);
                 if (!page) {
                         pr_err("find_or_create_page() failed\n");
                         ret = -ENOMEM;
-                        goto next_page;
+                        goto out;
                 }
 
                 if (PageUptodate(page)) {
@@ -3255,39 +3259,49 @@ static int copy_nocow_pages_for_inode(u64 inum, u64 offset, u64 root, void *ctx)
                                 goto next_page;
                 } else {
                         ClearPageError(page);
-                        ret_sub = extent_read_full_page(&BTRFS_I(inode)->
+                        err = extent_read_full_page(&BTRFS_I(inode)->
                                                          io_tree,
                                                         page, btrfs_get_extent,
                                                         nocow_ctx->mirror_num);
-                        if (ret_sub) {
-                                ret = ret_sub;
+                        if (err) {
+                                ret = err;
                                 goto next_page;
                         }
-                        wait_on_page_locked(page);
+
+                        lock_page(page);
+                        /*
+                         * If the page has been remove from the page cache,
+                         * the data on it is meaningless, because it may be
+                         * old one, the new data may be written into the new
+                         * page in the page cache.
+                         */
+                        if (page->mapping != inode->i_mapping) {
+                                page_cache_release(page);
+                                goto again;
+                        }
                         if (!PageUptodate(page)) {
                                 ret = -EIO;
                                 goto next_page;
                         }
                 }
-                ret_sub = write_page_nocow(nocow_ctx->sctx,
-                                           physical_for_dev_replace, page);
-                if (ret_sub) {
-                        ret = ret_sub;
-                        goto next_page;
-                }
-
+                err = write_page_nocow(nocow_ctx->sctx,
+                                       physical_for_dev_replace, page);
+                if (err)
+                        ret = err;
 next_page:
-                if (page) {
-                        unlock_page(page);
-                        put_page(page);
-                }
+                unlock_page(page);
+                page_cache_release(page);
+
+                if (ret)
+                        break;
+
                 offset += PAGE_CACHE_SIZE;
                 physical_for_dev_replace += PAGE_CACHE_SIZE;
                 len -= PAGE_CACHE_SIZE;
         }
-
-        if (inode)
-                iput(inode);
+out:
+        mutex_unlock(&inode->i_mutex);
+        iput(inode);
         return ret;
 }