[PATCH v11 03/11] ext4: add ext4_dir_entry_is_tail()

From: Artem Blagodarenko <[email protected]>

Replace open-coded checks for directory tail entries with a call
to ext4_dir_entry_is_tail(). This helper will also be used by
upcoming changes.

Signed-off-by: Artem Blagodarenko <[email protected]>
Reviewed-by: Andreas Dilger <[email protected]>
---
 fs/ext4/ext4.h  | 16 ++++++++++++++++
 fs/ext4/namei.c | 14 ++++++--------
 2 files changed, 22 insertions(+), 8 deletions(-)

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index aa8a37566a38..f8d8d92391bf 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -4002,6 +4002,22 @@ static inline void ext4_clear_io_unwritten_flag(ext4_io_end_t *io_end)
 		io_end->flag &= ~EXT4_IO_END_UNWRITTEN;
 }
 
+/*
+ * ext4_dir_entry_is_tail() - Check if a directory entry is a tail entry.
+ * @de: directory entry to check
+ *
+ * Returns true if @de is a directory block tail entry (checksum record).
+ */
+static inline bool ext4_dir_entry_is_tail(struct ext4_dir_entry_2 *de)
+{
+	struct ext4_dir_entry_tail *t = (struct ext4_dir_entry_tail *)de;
+
+	return !t->det_reserved_zero1 &&
+	       le16_to_cpu(t->det_rec_len) == sizeof(*t) &&
+	       !t->det_reserved_zero2 &&
+	       t->det_reserved_ft == EXT4_FT_DIR_CSUM;
+}
+
 extern const struct iomap_ops ext4_iomap_ops;
 extern const struct iomap_ops ext4_iomap_report_ops;
 
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index c2f330c75c81..da12911bd754 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -331,14 +331,10 @@ static struct ext4_dir_entry_tail *get_dirent_tail(struct inode *inode,
 
 	t = (struct ext4_dir_entry_tail *)d;
 #else
-	t = EXT4_DIRENT_TAIL(bh->b_data, EXT4_BLOCK_SIZE(inode->i_sb));
+	t = EXT4_DIRENT_TAIL(bh->b_data, blocksize);
 #endif
 
-	if (t->det_reserved_zero1 ||
-	    (ext4_rec_len_from_disk(t->det_rec_len, blocksize) !=
-	     sizeof(struct ext4_dir_entry_tail)) ||
-	    t->det_reserved_zero2 ||
-	    t->det_reserved_ft != EXT4_FT_DIR_CSUM)
+	if (!ext4_dir_entry_is_tail((struct ext4_dir_entry_2 *)t))
 		return NULL;
 
 	return t;
@@ -478,7 +474,8 @@ static int ext4_dx_csum_verify(struct inode *inode,
 		return 0;
 	}
 	if (count > limit) {
-		EXT4_ERROR_INODE(inode, "dir seems corrupt?  Run e2fsck -D.");
+		EXT4_ERROR_INODE(inode, "dir seems corrupt (%i > %i)? "
+				 "Run e2fsck -D.", count, limit);
 		return 0;
 	}
 	t = (struct dx_tail *)(((struct dx_entry *)c) + limit);
@@ -511,7 +508,8 @@ static void ext4_dx_csum_set(struct inode *inode, struct ext4_dir_entry_2 *diren
 		return;
 	}
 	if (count > limit) {
-		EXT4_ERROR_INODE(inode, "dir seems corrupt?  Run e2fsck -D.");
+		EXT4_ERROR_INODE(inode, "dir seems corrupt (%i > %i)? "
+				 " Run e2fsck -D.", count, limit);
 		return;
 	}
 	t = (struct dx_tail *)(((struct dx_entry *)c) + limit);
-- 
2.43.7