Re: [PATCH] btrfs-progs: Get the highest inode for lost+found

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 





At 12/20/2016 08:08 PM, Goldwyn Rodrigues wrote:
From: Goldwyn Rodrigues <rgoldwyn@xxxxxxxx>

root->highest_inode is not accurate at the time of creating a lost+found
and it fails because the highest_inode+1 is already present. This could be
because of fixes after highest_inode is set. Instead, search
for the highest inode in the tree and use it for lost+found.

This makes root->highest_inode unnecessary and hence deleted.

This is much better than recording it in root.


Signed-off-by: Goldwyn Rodrigues <rgoldwyn@xxxxxxxx>
---
 cmds-check.c | 46 +++++++++++++++++++++++++++-------------------
 ctree.h      |  1 -
 disk-io.c    |  1 -
 3 files changed, 27 insertions(+), 21 deletions(-)

diff --git a/cmds-check.c b/cmds-check.c
index 1dba298..a55d00d 100644
--- a/cmds-check.c
+++ b/cmds-check.c
@@ -2853,6 +2853,31 @@ out:
 	return ret;
 }

+static int get_highest_inode(struct btrfs_trans_handle *trans,
+				struct btrfs_root *root,
+				struct btrfs_path *path,
+				u64 *highest_ino)
+{
+	struct btrfs_key key, found_key;
+	int ret;
+
+	btrfs_init_path(path);
+	key.objectid = BTRFS_LAST_FREE_OBJECTID;
+	key.offset = -1;
+	key.type = BTRFS_INODE_ITEM_KEY;
+	ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
+	if (ret == 1) {
+		btrfs_item_key_to_cpu(path->nodes[0], &found_key,
+				path->slots[0] - 1);
+		*highest_ino = found_key.objectid;
+		ret = 0;
+	}

I think such search may cause problem.

If the fs uses inode_map mount option, each fs tree will have a tailing FREE_INO and FREE_SPACE items.

And FREE_INO/FREE_SPACE are all over LAST_FREE_OBJECTID.

        item 0 key (256 INODE_ITEM 0) itemoff 16123 itemsize 160
                inode generation 3 transid 7 size 0 nbytes 16384
                block group 0 mode 40755 links 1 uid 0 gid 0 rdev 0
                sequence 0 flags 0x1(none)
        item 1 key (256 INODE_REF 256) itemoff 16111 itemsize 12
                inode ref index 0 namelen 2 name: ..
        item 2 key (FREE_INO INODE_ITEM 0) itemoff 15951 itemsize 160
                inode generation 0 transid 7 size 0 nbytes 0
                block group 0 mode 100600 links 1 uid 0 gid 0 rdev 0
                sequence 24 flags 0x0(NOCOMPRESS|PREALLOC)
        item 3 key (FREE_SPACE UNTYPED 0) itemoff 15910 itemsize 41
                location key (FREE_INO INODE_ITEM 0)
                cache generation 0 entries 0 bitmaps 0


In that case, such search will point to the FREE_INO slot, and always return -EOVERFLOW.

What about check the objectid and if it's larger than LAST_FREE_OBJECTID, try to search previous slot?

Other part looks good for me.

Thanks,
Qu
+	if (*highest_ino >= BTRFS_LAST_FREE_OBJECTID)
+		ret = -EOVERFLOW;
+	btrfs_release_path(path);
+	return ret;
+}
+
 static int repair_inode_nlinks(struct btrfs_trans_handle *trans,
 			       struct btrfs_root *root,
 			       struct btrfs_path *path,
@@ -2898,11 +2923,9 @@ static int repair_inode_nlinks(struct btrfs_trans_handle *trans,
 	}

 	if (rec->found_link == 0) {
-		lost_found_ino = root->highest_inode;
-		if (lost_found_ino >= BTRFS_LAST_FREE_OBJECTID) {
-			ret = -EOVERFLOW;
+		ret = get_highest_inode(trans, root, path, &lost_found_ino);
+		if (ret < 0)
 			goto out;
-		}
 		lost_found_ino++;
 		ret = btrfs_mkdir(trans, root, dir_name, strlen(dir_name),
 				  BTRFS_FIRST_FREE_OBJECTID, &lost_found_ino,
@@ -3266,21 +3289,6 @@ static int check_inode_recs(struct btrfs_root *root,
 	}

 	/*
-	 * We need to record the highest inode number for later 'lost+found'
-	 * dir creation.
-	 * We must select an ino not used/referred by any existing inode, or
-	 * 'lost+found' ino may be a missing ino in a corrupted leaf,
-	 * this may cause 'lost+found' dir has wrong nlinks.
-	 */
-	cache = last_cache_extent(inode_cache);
-	if (cache) {
-		node = container_of(cache, struct ptr_node, cache);
-		rec = node->data;
-		if (rec->ino > root->highest_inode)
-			root->highest_inode = rec->ino;
-	}
-
-	/*
 	 * We need to repair backrefs first because we could change some of the
 	 * errors in the inode recs.
 	 *
diff --git a/ctree.h b/ctree.h
index dd02ef8..0c34ae2 100644
--- a/ctree.h
+++ b/ctree.h
@@ -1177,7 +1177,6 @@ struct btrfs_root {


 	u32 type;
-	u64 highest_inode;
 	u64 last_inode_alloc;

 	/*
diff --git a/disk-io.c b/disk-io.c
index 9140a81..2a94d4f 100644
--- a/disk-io.c
+++ b/disk-io.c
@@ -494,7 +494,6 @@ void btrfs_setup_root(u32 nodesize, u32 leafsize, u32 sectorsize,
 	root->fs_info = fs_info;
 	root->objectid = objectid;
 	root->last_trans = 0;
-	root->highest_inode = 0;
 	root->last_inode_alloc = 0;

 	INIT_LIST_HEAD(&root->dirty_list);



--
To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html




[Index of Archives]     [Linux Filesystem Development]     [Linux NFS]     [Linux NILFS]     [Linux USB Devel]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]

  Powered by Linux