ext4: Split uninitialized extents for direct I/O

When writing into an unitialized extent via direct I/O, and the direct
I/O doesn't exactly cover the unitialized extent, split the extent
into uninitialized and initialized extents before submitting the I/O.
This avoids needing to deal with an ENOSPC error in the end_io
callback that gets used for direct I/O.

When the IO is complete, the written extent will be marked as initialized.

Singed-Off-By: Mingming Cao <cmm@us.ibm.com> 
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

1 files changed, 6 insertions, 1 deletions

diff --git a/fs/ext4/ext4_extents.h b/fs/ext4/ext4_extents.h
index 61652f1d15e6..2ca686454e87 100644
--- a/fs/ext4/ext4_extents.h
+++ b/fs/ext4/ext4_extents.h
@@ -220,6 +220,11 @@ static inline int ext4_ext_get_actual_len(struct ext4_extent *ext)
                 (le16_to_cpu(ext->ee_len) - EXT_INIT_MAX_LEN));
 }
 
+static inline void ext4_ext_mark_initialized(struct ext4_extent *ext)
+{
+        ext->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ext));
+}
+
 extern int ext4_ext_calc_metadata_amount(struct inode *inode, int blocks);
 extern ext4_fsblk_t ext_pblock(struct ext4_extent *ex);
 extern ext4_fsblk_t idx_pblock(struct ext4_extent_idx *);
@@ -235,7 +240,7 @@ extern int ext4_ext_try_to_merge(struct inode *inode,
                                  struct ext4_ext_path *path,
                                  struct ext4_extent *);
 extern unsigned int ext4_ext_check_overlap(struct inode *, struct ext4_extent *, struct ext4_ext_path *);
-extern int ext4_ext_insert_extent(handle_t *, struct inode *, struct ext4_ext_path *, struct ext4_extent *);
+extern int ext4_ext_insert_extent(handle_t *, struct inode *, struct ext4_ext_path *, struct ext4_extent *, int);
 extern int ext4_ext_walk_space(struct inode *, ext4_lblk_t, ext4_lblk_t,
                                                         ext_prepare_callback, void *);
 extern struct ext4_ext_path *ext4_ext_find_extent(struct inode *, ext4_lblk_t,