ext4: move set iomap routines into a separate helper ext4_set_iomap()

Separate the iomap field population code that is currently within
ext4_iomap_begin() into a separate helper ext4_set_iomap(). The intent
of this function is self explanatory, however the rationale behind
taking this step is to reeduce the overall clutter that we currently
have within the ext4_iomap_begin() callback.

Signed-off-by: Matthew Bobrowski <mbobrowski@mbobrowski.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Ritesh Harjani <riteshh@linux.ibm.com>
Link: https://lore.kernel.org/r/1ea34da65eecffcddffb2386668ae06134e8deaf.1572949325.git.mbobrowski@mbobrowski.org
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index b422d9b8c0bd7b95e8f81fef874fa0f25635beae..9e1ac9fe816b6133fd67bdbc24d9be3ea96b5081 100644 (file)
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -3448,10 +3448,54 @@ static bool ext4_inode_datasync_dirty(struct inode *inode)
        return inode->i_state & I_DIRTY_DATASYNC;
 }
 
+static void ext4_set_iomap(struct inode *inode, struct iomap *iomap,
+                          struct ext4_map_blocks *map, loff_t offset,
+                          loff_t length)
+{
+       u8 blkbits = inode->i_blkbits;
+
+       /*
+        * Writes that span EOF might trigger an I/O size update on completion,
+        * so consider them to be dirty for the purpose of O_DSYNC, even if
+        * there is no other metadata changes being made or are pending.
+        */
+       iomap->flags = 0;
+       if (ext4_inode_datasync_dirty(inode) ||
+           offset + length > i_size_read(inode))
+               iomap->flags |= IOMAP_F_DIRTY;
+
+       if (map->m_flags & EXT4_MAP_NEW)
+               iomap->flags |= IOMAP_F_NEW;
+
+       iomap->bdev = inode->i_sb->s_bdev;
+       iomap->dax_dev = EXT4_SB(inode->i_sb)->s_daxdev;
+       iomap->offset = (u64) map->m_lblk << blkbits;
+       iomap->length = (u64) map->m_len << blkbits;
+
+       /*
+        * Flags passed to ext4_map_blocks() for direct I/O writes can result
+        * in m_flags having both EXT4_MAP_MAPPED and EXT4_MAP_UNWRITTEN bits
+        * set. In order for any allocated unwritten extents to be converted
+        * into written extents correctly within the ->end_io() handler, we
+        * need to ensure that the iomap->type is set appropriately. Hence, the
+        * reason why we need to check whether the EXT4_MAP_UNWRITTEN bit has
+        * been set first.
+        */
+       if (map->m_flags & EXT4_MAP_UNWRITTEN) {
+               iomap->type = IOMAP_UNWRITTEN;
+               iomap->addr = (u64) map->m_pblk << blkbits;
+       } else if (map->m_flags & EXT4_MAP_MAPPED) {
+               iomap->type = IOMAP_MAPPED;
+               iomap->addr = (u64) map->m_pblk << blkbits;
+       } else {
+               iomap->type = IOMAP_HOLE;
+               iomap->addr = IOMAP_NULL_ADDR;
+       }
+}
+
 static int ext4_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
                unsigned flags, struct iomap *iomap, struct iomap *srcmap)
 {
-       struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
        unsigned int blkbits = inode->i_blkbits;
        unsigned long first_block, last_block;
        struct ext4_map_blocks map;
@@ -3565,47 +3609,9 @@ static int ext4_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
                        return ret;
        }
 
-       /*
-        * Writes that span EOF might trigger an I/O size update on completion,
-        * so consider them to be dirty for the purposes of O_DSYNC, even if
-        * there is no other metadata changes being made or are pending here.
-        */
-       iomap->flags = 0;
-       if (ext4_inode_datasync_dirty(inode) ||
-           offset + length > i_size_read(inode))
-               iomap->flags |= IOMAP_F_DIRTY;
-       iomap->bdev = inode->i_sb->s_bdev;
-       iomap->dax_dev = sbi->s_daxdev;
-       iomap->offset = (u64)first_block << blkbits;
-       iomap->length = (u64)map.m_len << blkbits;
-
-       if (ret == 0) {
-               iomap->type = delalloc ? IOMAP_DELALLOC : IOMAP_HOLE;
-               iomap->addr = IOMAP_NULL_ADDR;
-       } else {
-               /*
-                * Flags passed into ext4_map_blocks() for direct I/O writes
-                * can result in m_flags having both EXT4_MAP_MAPPED and
-                * EXT4_MAP_UNWRITTEN bits set. In order for any allocated
-                * unwritten extents to be converted into written extents
-                * correctly within the ->end_io() handler, we need to ensure
-                * that the iomap->type is set appropriately. Hence the reason
-                * why we need to check whether EXT4_MAP_UNWRITTEN is set
-                * first.
-                */
-               if (map.m_flags & EXT4_MAP_UNWRITTEN) {
-                       iomap->type = IOMAP_UNWRITTEN;
-               } else if (map.m_flags & EXT4_MAP_MAPPED) {
-                       iomap->type = IOMAP_MAPPED;
-               } else {
-                       WARN_ON_ONCE(1);
-                       return -EIO;
-               }
-               iomap->addr = (u64)map.m_pblk << blkbits;
-       }
-
-       if (map.m_flags & EXT4_MAP_NEW)
-               iomap->flags |= IOMAP_F_NEW;
+       ext4_set_iomap(inode, iomap, &map, offset, length);
+       if (delalloc && iomap->type == IOMAP_HOLE)
+               iomap->type = IOMAP_DELALLOC;
 
        return 0;
 }