e2fsck: check for an encrypted lost+found directory

The /lost+found directory must not be encrypted, since e2fsck won't
have any keys.  If we find an encrypted lost+found directory, we
should delete the directory and recreate it.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>

e2fsck/pass3.c

@@ -100,7 +100,8 @@ void e2fsck_pass3(e2fsck_t ctx)
 
 	iter = e2fsck_dir_info_iter_begin(ctx);
 	while ((dir = e2fsck_dir_info_iter(ctx, iter)) != 0) {
-		if (ctx->flags & E2F_FLAG_SIGNAL_MASK)
+		if (ctx->flags & E2F_FLAG_SIGNAL_MASK ||
+		    ctx->flags & E2F_FLAG_RESTART)
 			goto abort_exit;
 		if (ctx->progress && (ctx->progress)(ctx, 3, count++, maxdirs))
 			goto abort_exit;
@@ -415,6 +416,12 @@ ext2_ino_t e2fsck_get_lost_and_found(e2fsck_t ctx, int fix)
 			goto unlink;
 		}
 
+		if (fix && (inode.i_flags & EXT4_ENCRYPT_FL)) {
+			if (!fix_problem(ctx, PR_3_LPF_ENCRYPTED, &pctx))
+				return 0;
+			goto unlink;
+		}
+
 		if (ext2fs_check_directory(fs, ino) == 0) {
 			ctx->lost_and_found = ino;
 			return ino;
@@ -437,6 +444,15 @@ unlink:
 		}
 		(void) e2fsck_dir_info_set_parent(ctx, ino, 0);
 		e2fsck_adjust_inode_count(ctx, ino, -1);
+		/*
+		 * If the old lost+found was a directory, we've just
+		 * disconnected it from the directory tree, which
+		 * means we need to restart the directory tree scan.
+		 * The simplest way to do this is restart the whole
+		 * e2fsck operation.
+		 */
+		if (LINUX_S_ISDIR(inode.i_mode))
+			ctx->flags |= E2F_FLAG_RESTART;
 	} else if (retval != EXT2_ET_FILE_NOT_FOUND) {
 		pctx.errcode = retval;
 		fix_problem(ctx, PR_3_ERR_FIND_LPF, &pctx);

e2fsck/problem.c

@@ -1750,6 +1750,11 @@ static struct e2fsck_problem problem_table[] = {
 	  N_("Insufficient space to recover lost files!\nMove data off the @f and re-run e2fsck.\n\n"),
 	  PROMPT_NONE, 0 },
 
+	/* Lost+found is encrypted */
+	{ PR_3_LPF_ENCRYPTED,
+	  N_("/@l is encrypted\n"),
+	  PROMPT_CLEAR, 0 },
+
 	/* Pass 3A Directory Optimization	*/
 
 	/* Pass 3A: Optimizing directories */

e2fsck/problem.h

@@ -1048,6 +1048,9 @@ struct problem_context {
 /* Insufficient space to recover lost files */
 #define PR_3_NO_SPACE_TO_RECOVER	0x03001A
 
+/* Lost+found is encrypted */
+#define PR_3_LPF_ENCRYPTED		0x03001B
+
 /*
  * Pass 3a --- rehashing diretories
  */

tests/f_encrypted_lpf/expect.1

@@ -0,0 +1,27 @@
+Pass 1: Checking inodes, blocks, and sizes
+Pass 2: Checking directory structure
+Pass 3: Checking directory connectivity
+Unconnected directory inode 12 (/???)
+Connect to /lost+found? yes
+
+/lost+found is encrypted
+Clear? yes
+
+/lost+found not found.  Create? yes
+
+Restarting e2fsck from the beginning...
+Pass 1: Checking inodes, blocks, and sizes
+Pass 2: Checking directory structure
+Pass 3: Checking directory connectivity
+Unconnected directory inode 11 (/???)
+Connect to /lost+found? yes
+
+Pass 3A: Optimizing directories
+Pass 4: Checking reference counts
+Inode 12 ref count is 3, should be 2.  Fix? yes
+
+Pass 5: Checking group summary information
+
+test_filesys: ***** FILE SYSTEM WAS MODIFIED *****
+test_filesys: 13/64 files (0.0% non-contiguous), 13/100 blocks
+Exit status is 1

tests/f_encrypted_lpf/expect.2

@@ -0,0 +1,7 @@
+Pass 1: Checking inodes, blocks, and sizes
+Pass 2: Checking directory structure
+Pass 3: Checking directory connectivity
+Pass 4: Checking reference counts
+Pass 5: Checking group summary information
+test_filesys: 13/64 files (0.0% non-contiguous), 13/100 blocks
+Exit status is 0

tests/f_encrypted_lpf/name

@@ -0,0 +1 @@
+encrypted lost+found directory