[PATCH V2 4/4] ext4: Notify block device about alloc-assigned blk

[Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>]

From: Kirill Tkhai <ktkhai@virtuozzo.com>

Call sb_issue_allocate() after extent range was allocated on user
request. Hopeful, this helps block device to maintain its internals in
the best way, if this is appliable.

Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
---
 fs/ext4/ext4.h    |  2 ++
 fs/ext4/extents.c | 12 +++++++++++-
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 61b37a052052..0d0fa9904147 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -622,6 +622,8 @@ enum {
 	 * allows jbd2 to avoid submitting data before commit. */
 #define EXT4_GET_BLOCKS_IO_SUBMIT		0x0400
 
+#define EXT4_GET_BLOCKS_SUBMIT_ALLOC		0x0800
+
 /*
  * The bit position of these flags must not overlap with any of the
  * EXT4_GET_BLOCKS_*.  They are used by ext4_find_extent(),
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 954013d6076b..37a60e190349 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -4449,6 +4449,14 @@ int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
 		ar.len = allocated;
 
 got_allocated_blocks:
+	if ((flags & EXT4_GET_BLOCKS_SUBMIT_ALLOC) &&
+			inode->i_fop->fallocate) {
+		err = sb_issue_allocate(inode->i_sb, newblock,
+				EXT4_C2B(sbi, allocated_clusters), GFP_NOFS);
+		if (err)
+			goto free_on_err;
+	}
+
 	/* try to insert new extent into found leaf and return */
 	ext4_ext_store_pblock(&newex, newblock + offset);
 	newex.ee_len = cpu_to_le16(ar.len);
@@ -4466,6 +4474,7 @@ int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
 		err = ext4_ext_insert_extent(handle, inode, &path,
 					     &newex, flags);
 
+free_on_err:
 	if (err && free_on_err) {
 		int fb_flags = flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE ?
 			EXT4_FREE_BLOCKS_NO_QUOT_UPDATE : 0;
@@ -4733,7 +4742,8 @@ static long ext4_zero_range(struct file *file, loff_t offset,
 			goto out_mutex;
 	}
 
-	flags = EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT;
+	flags = EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT |
+		EXT4_GET_BLOCKS_SUBMIT_ALLOC;
 	if (mode & FALLOC_FL_KEEP_SIZE)
 		flags |= EXT4_GET_BLOCKS_KEEP_SIZE;
 
-- 
2.22.0