ext4: remove unreachable code after ext4_can_extents_be_merged()

Commit ec22ba8e ("ext4: disable merging of uninitialized extents")
ensured that if either extent under consideration is uninit, we
decline to merge, and ext4_can_extents_be_merged() returns false.

So there is no need for the caller to then test whether the
extent under consideration is unitialized; if it were, we
wouldn't have gotten that far.

The comments were also inaccurate; ext4_can_extents_be_merged()
no longer XORs the states, it fails if *either* is uninit.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Reviewed-by: Zheng Liu <wenqing.lz@taobao.com>

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index de6d4674ba6ead8846903e752fa1ea6855204c42..35f65cf4f318d72bce4e79995ddbc85d0e4bbfa3 100644 (file)
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -1715,7 +1715,6 @@ static int ext4_ext_try_to_merge_right(struct inode *inode,
        struct ext4_extent_header *eh;
        unsigned int depth, len;
        int merge_done = 0;
-       int uninitialized = 0;
 
        depth = ext_depth(inode);
        BUG_ON(path[depth].p_hdr == NULL);
@@ -1725,12 +1724,8 @@ static int ext4_ext_try_to_merge_right(struct inode *inode,
                if (!ext4_can_extents_be_merged(inode, ex, ex + 1))
                        break;
                /* merge with next extent! */
-               if (ext4_ext_is_uninitialized(ex))
-                       uninitialized = 1;
                ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
                                + ext4_ext_get_actual_len(ex + 1));
-               if (uninitialized)
-                       ext4_ext_mark_uninitialized(ex);
 
                if (ex + 1 < EXT_LAST_EXTENT(eh)) {
                        len = (EXT_LAST_EXTENT(eh) - ex - 1)
@@ -1885,7 +1880,6 @@ int ext4_ext_insert_extent(handle_t *handle, struct inode *inode,
        struct ext4_ext_path *npath = NULL;
        int depth, len, err;
        ext4_lblk_t next;
-       unsigned uninitialized = 0;
        int mb_flags = 0;
 
        if (unlikely(ext4_ext_get_actual_len(newext) == 0)) {
@@ -1937,18 +1931,8 @@ int ext4_ext_insert_extent(handle_t *handle, struct inode *inode,
                        if (err)
                                return err;
 
-                       /*
-                        * ext4_can_extents_be_merged should have checked
-                        * that either both extents are uninitialized, or
-                        * both aren't. Thus we need to check only one of
-                        * them here.
-                        */
-                       if (ext4_ext_is_uninitialized(ex))
-                               uninitialized = 1;
                        ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
                                        + ext4_ext_get_actual_len(newext));
-                       if (uninitialized)
-                               ext4_ext_mark_uninitialized(ex);
                        eh = path[depth].p_hdr;
                        nearex = ex;
                        goto merge;
@@ -1971,20 +1955,10 @@ prepend:
                        if (err)
                                return err;
 
-                       /*
-                        * ext4_can_extents_be_merged should have checked
-                        * that either both extents are uninitialized, or
-                        * both aren't. Thus we need to check only one of
-                        * them here.
-                        */
-                       if (ext4_ext_is_uninitialized(ex))
-                               uninitialized = 1;
                        ex->ee_block = newext->ee_block;
                        ext4_ext_store_pblock(ex, ext4_ext_pblock(newext));
                        ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
                                        + ext4_ext_get_actual_len(newext));
-                       if (uninitialized)
-                               ext4_ext_mark_uninitialized(ex);
                        eh = path[depth].p_hdr;
                        nearex = ex;
                        goto merge;