This series address an issue of btrfsck to restore infinite number of same file into `lost+found' directory. The issue occur on a file which is linked from two different directory A and B. If links from dir A is corrupted and links from dir B is kept valid, btrfsck won't stop creating a file in lost+found like this:
----- Moving file 'file.del.51' to 'lost+found' dir since it has no valid backref Fixed the nlink of inode 1876 Trying to rebuild inode:1877 Moving file 'del' to 'lost+found' dir since it has no valid backref Fixed the nlink of inode 1877 Can't get file name for inode 1876, using '1876' as fallback Moving file '1876' to 'lost+found' dir since it has no valid backref Fixed the nlink of inode 1876 Can't get file name for inode 1876, using '1876' as fallback Moving file '1876.1876' to 'lost+found' dir since it has no valid backref Fixed the nlink of inode 1876 (snip) Moving file '1876.1876.1876.1876.1876.1876.1876.1876.1876.1876.1876.1876.1876.1876.1876.1876.1876.1876.1876.1876.1876.1876.1876.1876.1876.1876.1876.1876.1876.1876.1876.1876.1876.1876.1876.1876.1876.1876.1876.1876.1876.1876.1876.1876.1876.1876.1876.1876.1876.1876.1876' to 'lost+found' dir since it has no valid backref Fixed the nlink of inode 1876 Can't get file name for inode 1876, using '1876' as fallback Can't get file name for inode 1876, using '1876' as fallback Can't get file name for inode 1876, using '1876' as fallback ----- The problem is early release of inode backrefs. The release prevents `reset_nlink()' to add back valid backrefs to an inode. In the result, the following results occur: 0. btrfsck scan a FS tree 1. It finds valid links and invalid links (some links are lost) 2. All valid links are released 3. btrfsck detects found_links != nlink 4. reset_nlink() reset nlink to 0 5. No valid links are restored (thus still nlink = 0) 6. The file is restored to lost+found since nlink == 0 (now, nlink = 1) 7. btrfsck rescan the FS tree 8. It finds `found_links' = #valid_links+1 (in lost+found) and nlink = 1 9. again all valid links are lost, and restore to lost+found The first patch add clean up code to the test. It umount test directory on failure path. The second patch fix the above problem. And the last patch extend the test to check a case of multiple-linked file corruption. -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
