ext4: merge uninitialized extents

Allow for merging uninitialized extents.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 9875fd0918e79d4aef24c77648b729b21117546e..ef4b535e0a02715f95c38adff015fd36f2cfcdad 100644 (file)
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -1691,7 +1691,7 @@ ext4_can_extents_be_merged(struct inode *inode, struct ext4_extent *ex1,
         * the extent that was written properly split out and conversion to
         * initialized is trivial.
         */
-       if (ext4_ext_is_uninitialized(ex1) || ext4_ext_is_uninitialized(ex2))
+       if (ext4_ext_is_uninitialized(ex1) != ext4_ext_is_uninitialized(ex2))
                return 0;
 
        ext1_ee_len = ext4_ext_get_actual_len(ex1);
@@ -1708,6 +1708,11 @@ ext4_can_extents_be_merged(struct inode *inode, struct ext4_extent *ex1,
         */
        if (ext1_ee_len + ext2_ee_len > EXT_INIT_MAX_LEN)
                return 0;
+       if (ext4_ext_is_uninitialized(ex1) &&
+           (ext4_test_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN) ||
+            atomic_read(&EXT4_I(inode)->i_unwritten) ||
+            (ext1_ee_len + ext2_ee_len > EXT_UNINIT_MAX_LEN)))
+               return 0;
 #ifdef AGGRESSIVE_TEST
        if (ext1_ee_len >= 4)
                return 0;
@@ -1731,7 +1736,7 @@ 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 merge_done = 0, uninit;
 
        depth = ext_depth(inode);
        BUG_ON(path[depth].p_hdr == NULL);
@@ -1741,8 +1746,11 @@ 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! */
+               uninit = ext4_ext_is_uninitialized(ex);
                ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
                                + ext4_ext_get_actual_len(ex + 1));
+               if (uninit)
+                       ext4_ext_mark_uninitialized(ex);
 
                if (ex + 1 < EXT_LAST_EXTENT(eh)) {
                        len = (EXT_LAST_EXTENT(eh) - ex - 1)
@@ -1896,7 +1904,7 @@ 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;
-       int mb_flags = 0;
+       int mb_flags = 0, uninit;
 
        if (unlikely(ext4_ext_get_actual_len(newext) == 0)) {
                EXT4_ERROR_INODE(inode, "ext4_ext_get_actual_len(newext) == 0");
@@ -1946,9 +1954,11 @@ int ext4_ext_insert_extent(handle_t *handle, struct inode *inode,
                                                  path + depth);
                        if (err)
                                return err;
-
+                       uninit = ext4_ext_is_uninitialized(ex);
                        ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
                                        + ext4_ext_get_actual_len(newext));
+                       if (uninit)
+                               ext4_ext_mark_uninitialized(ex);
                        eh = path[depth].p_hdr;
                        nearex = ex;
                        goto merge;
@@ -1971,10 +1981,13 @@ prepend:
                        if (err)
                                return err;
 
+                       uninit = ext4_ext_is_uninitialized(ex);
                        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 (uninit)
+                               ext4_ext_mark_uninitialized(ex);
                        eh = path[depth].p_hdr;
                        nearex = ex;
                        goto merge;