- It makes no sense that we deal with a inode in the dead tree.
- fix the race between dio and page copy by waiting the dio completion
- avoid the page copy vs truncate/punch hole
- check if the page is in the page cache or not
Signed-off-by: Miao Xie <mi...@cn.fujitsu.com>
---
fs/btrfs/scrub.c | 23 ++++++++++++++++++++++-
1 file changed, 22 insertions(+), 1 deletion(-)
diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index 186ea82..4ba2a69 100644
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -3224,6 +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;
@@ -3232,12 +3237,16 @@ 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) {
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");
@@ -3258,7 +3267,18 @@ static int copy_nocow_pages_for_inode(u64 inum, u64
offset, u64 root, void *ctx)
ret = err;
goto next_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;
@@ -3280,6 +3300,7 @@ next_page:
len -= PAGE_CACHE_SIZE;
}
out:
+ mutex_unlock(&inode->i_mutex);
iput(inode);
return ret;
}
--
1.8.1.4
--
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