[PATCH v2] ocfs2: fix hung task in orphan recovery

[Jiaming Zhang]

A crafted OCFS2 image with corrupted orphan-directory extent metadata can make
umount hang.

During unmount, ocfs2_recovery_disable() waits for the ocfs2_complete_recovery
work item to finish. The worker scans the orphan directory through
ocfs2_queue_orphans() and ocfs2_dir_foreach(). If ocfs2_read_dir_block() fails
on a corrupted directory block, ocfs2_dir_foreach_blk_el() skips the block and
continues walking. On a badly corrupted directory this can keep orphan recovery
busy for a long time, leaving umount blocked while flushing osb->ocfs2_wq.

Return the read error immediately for full directory scans and propagate the
error from ocfs2_dir_foreach(). When ocfs2_empty_dir() receives such an error,
report the directory as non-empty so unlink/rmdir does not proceed on an
unreadable directory.

Closes: https://lore.kernel.org/lkml/CANypQFbWH76Y6LWHEwAvTP7aQL04uMJ=dDyL6YDmxa3fv3Tyjg@xxxxxxxxxxxxxx/
Assisted-by: Codex:gpt-5.5-xhigh
Signed-off-by: Jiaming Zhang <r772577952@xxxxxxxxx>
---
Changes in v2:
- Propagate the actual error from ocfs2_empty_dir() to caller.
- Update ocfs2_unlink() and ocfs2_rename() to distinguish errors from a
  non-empty directory result.

 fs/ocfs2/dir.c   | 20 ++++++++++++++------
 fs/ocfs2/namei.c | 11 ++++++++---
 2 files changed, 22 insertions(+), 9 deletions(-)

diff --git a/fs/ocfs2/dir.c b/fs/ocfs2/dir.c
index 8e6b03238327..baf3eca7b4e4 100644
--- a/fs/ocfs2/dir.c
+++ b/fs/ocfs2/dir.c
@@ -1866,6 +1866,7 @@ static int ocfs2_dir_foreach_blk_el(struct inode *inode,
 	struct super_block * sb = inode->i_sb;
 	unsigned int ra_sectors = 16;
 	int stored = 0;
+	int ret;
 
 	bh = NULL;
 
@@ -1873,9 +1874,13 @@ static int ocfs2_dir_foreach_blk_el(struct inode *inode,
 
 	while (ctx->pos < i_size_read(inode)) {
 		blk = ctx->pos >> sb->s_blocksize_bits;
-		if (ocfs2_read_dir_block(inode, blk, &bh, 0)) {
+		ret = ocfs2_read_dir_block(inode, blk, &bh, 0);
+		if (ret) {
+			if (persist)
+				return ret;
 			/* Skip the corrupt dirblock and keep trying */
 			ctx->pos += sb->s_blocksize - offset;
+			offset = 0;
 			continue;
 		}
 
@@ -1969,8 +1974,7 @@ static int ocfs2_dir_foreach_blk(struct inode *inode, u64 *f_version,
 int ocfs2_dir_foreach(struct inode *inode, struct dir_context *ctx)
 {
 	u64 version = inode_query_iversion(inode);
-	ocfs2_dir_foreach_blk(inode, &version, ctx, true);
-	return 0;
+	return ocfs2_dir_foreach_blk(inode, &version, ctx, true);
 }
 
 /*
@@ -2167,7 +2171,7 @@ static int ocfs2_empty_dir_dx(struct inode *inode,
 /*
  * routine to check that the specified directory is empty (for rmdir)
  *
- * Returns 1 if dir is empty, zero otherwise.
+ * Returns 1 if dir is empty, zero if not, and a negative errno on error.
  *
  * XXX: This is a performance problem for unindexed directories.
  */
@@ -2180,8 +2184,10 @@ int ocfs2_empty_dir(struct inode *inode)
 
 	if (ocfs2_dir_indexed(inode)) {
 		ret = ocfs2_empty_dir_dx(inode, &priv);
-		if (ret)
+		if (ret) {
 			mlog_errno(ret);
+			return ret;
+		}
 		/*
 		 * We still run ocfs2_dir_foreach to get the checks
 		 * for "." and "..".
@@ -2189,8 +2195,10 @@ int ocfs2_empty_dir(struct inode *inode)
 	}
 
 	ret = ocfs2_dir_foreach(inode, &priv.ctx);
-	if (ret)
+	if (ret) {
 		mlog_errno(ret);
+		return ret;
+	}
 
 	if (!priv.seen_dot || !priv.seen_dot_dot) {
 		mlog(ML_ERROR, "bad directory (dir #%llu) - no `.' or `..'\n",
diff --git a/fs/ocfs2/namei.c b/fs/ocfs2/namei.c
index 1277666c77cd..abce59e1f180 100644
--- a/fs/ocfs2/namei.c
+++ b/fs/ocfs2/namei.c
@@ -945,7 +945,10 @@ static int ocfs2_unlink(struct inode *dir,
 	child_locked = 1;
 
 	if (S_ISDIR(inode->i_mode)) {
-		if (inode->i_nlink != 2 || !ocfs2_empty_dir(inode)) {
+		status = ocfs2_empty_dir(inode);
+		if (status < 0)
+			goto leave;
+		if (inode->i_nlink != 2 || !status) {
 			status = -ENOTEMPTY;
 			goto leave;
 		}
@@ -1499,8 +1502,10 @@ static int ocfs2_rename(struct mnt_idmap *idmap,
 
 	if (target_exists) {
 		if (S_ISDIR(new_inode->i_mode)) {
-			if (new_inode->i_nlink != 2 ||
-			    !ocfs2_empty_dir(new_inode)) {
+			status = ocfs2_empty_dir(new_inode);
+			if (status < 0)
+				goto bail;
+			if (new_inode->i_nlink != 2 || !status) {
 				status = -ENOTEMPTY;
 				goto bail;
 			}
-- 
2.43.0