[PATCH 06/10] ext4: update delalloc data reserve spcae in ext4_es_insert_extent()

[Zhang Yi]

From: Zhang Yi <yi.zhang@xxxxxxxxxx>

Now that we update data reserved space for delalloc after allocating
new blocks in ext4_{ind|ext}_map_blocks(), and if bigalloc feature is
enabled, we also need to query the extents_status tree to calculate the
exact reserved clusters. This is complicated now and it appears that
it's better to do this job in ext4_es_insert_extent(), because
__es_remove_extent() have already count delalloc blocks when removing
delalloc extents and __revise_pending() return new adding pending count,
we could update the reserved blocks easily in ext4_es_insert_extent().

Thers is one special case needs to concern is the quota claiming, when
bigalloc is enabled, if the delayed cluster allocation has been raced
by another no-delayed allocation(e.g. from fallocate) which doesn't
cover the delayed blocks:

  |<       one cluster       >|
  hhhhhhhhhhhhhhhhhhhdddddddddd
  ^            ^
  |<          >| < fallocate this range, don't claim quota again

We can't claim quota as usual because the fallocate has already claimed
it in ext4_mb_new_blocks(), we could notice this case through the
removed delalloc blocks count.

Signed-off-by: Zhang Yi <yi.zhang@xxxxxxxxxx>
---
 fs/ext4/extents.c        | 37 -------------------------------------
 fs/ext4/extents_status.c | 22 +++++++++++++++++++++-
 fs/ext4/indirect.c       |  7 -------
 3 files changed, 21 insertions(+), 45 deletions(-)

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index e57054bdc5fd..8bc8a519f745 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -4355,43 +4355,6 @@ int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
 		goto out;
 	}
 
-	/*
-	 * Reduce the reserved cluster count to reflect successful deferred
-	 * allocation of delayed allocated clusters or direct allocation of
-	 * clusters discovered to be delayed allocated.  Once allocated, a
-	 * cluster is not included in the reserved count.
-	 */
-	if (test_opt(inode->i_sb, DELALLOC) && allocated_clusters) {
-		if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) {
-			/*
-			 * When allocating delayed allocated clusters, simply
-			 * reduce the reserved cluster count and claim quota
-			 */
-			ext4_da_update_reserve_space(inode, allocated_clusters,
-							1);
-		} else {
-			ext4_lblk_t lblk, len;
-			unsigned int n;
-
-			/*
-			 * When allocating non-delayed allocated clusters
-			 * (from fallocate, filemap, DIO, or clusters
-			 * allocated when delalloc has been disabled by
-			 * ext4_nonda_switch), reduce the reserved cluster
-			 * count by the number of allocated clusters that
-			 * have previously been delayed allocated.  Quota
-			 * has been claimed by ext4_mb_new_blocks() above,
-			 * so release the quota reservations made for any
-			 * previously delayed allocated clusters.
-			 */
-			lblk = EXT4_LBLK_CMASK(sbi, map->m_lblk);
-			len = allocated_clusters << sbi->s_cluster_bits;
-			n = ext4_es_delayed_clu(inode, lblk, len);
-			if (n > 0)
-				ext4_da_update_reserve_space(inode, (int) n, 0);
-		}
-	}
-
 	/*
 	 * Cache the extent and update transaction to commit on fdatasync only
 	 * when it is _not_ an unwritten extent.
diff --git a/fs/ext4/extents_status.c b/fs/ext4/extents_status.c
index ced9826682bb..841f2f6d536d 100644
--- a/fs/ext4/extents_status.c
+++ b/fs/ext4/extents_status.c
@@ -856,6 +856,8 @@ void ext4_es_insert_extent(struct inode *inode, ext4_lblk_t lblk,
 	struct extent_status newes;
 	ext4_lblk_t end = lblk + len - 1;
 	int err1 = 0, err2 = 0, err3 = 0;
+	struct rsvd_info rinfo;
+	int resv_used, pending = 0;
 	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
 	struct extent_status *es1 = NULL;
 	struct extent_status *es2 = NULL;
@@ -894,7 +896,7 @@ void ext4_es_insert_extent(struct inode *inode, ext4_lblk_t lblk,
 		pr = __alloc_pending(true);
 	write_lock(&EXT4_I(inode)->i_es_lock);
 
-	err1 = __es_remove_extent(inode, lblk, end, NULL, es1);
+	err1 = __es_remove_extent(inode, lblk, end, &rinfo, es1);
 	if (err1 != 0)
 		goto error;
 	/* Free preallocated extent if it didn't get used. */
@@ -924,9 +926,27 @@ void ext4_es_insert_extent(struct inode *inode, ext4_lblk_t lblk,
 			__free_pending(pr);
 			pr = NULL;
 		}
+		pending = err3;
 	}
 error:
 	write_unlock(&EXT4_I(inode)->i_es_lock);
+	/*
+	 * Reduce the reserved cluster count to reflect successful deferred
+	 * allocation of delayed allocated clusters or direct allocation of
+	 * clusters discovered to be delayed allocated.  Once allocated, a
+	 * cluster is not included in the reserved count.
+	 *
+	 * When bigalloc is enabled, allocating non-delayed allocated blocks
+	 * which belong to delayed allocated clusters (from fallocate, filemap,
+	 * DIO, or clusters allocated when delalloc has been disabled by
+	 * ext4_nonda_switch()). Quota has been claimed by ext4_mb_new_blocks(),
+	 * so release the quota reservations made for any previously delayed
+	 * allocated clusters.
+	 */
+	resv_used = rinfo.delonly_cluster + pending;
+	if (resv_used)
+		ext4_da_update_reserve_space(inode, resv_used,
+					     rinfo.delonly_block);
 	if (err1 || err2 || err3 < 0)
 		goto retry;
 
diff --git a/fs/ext4/indirect.c b/fs/ext4/indirect.c
index d8ca7f64f952..7404f0935c90 100644
--- a/fs/ext4/indirect.c
+++ b/fs/ext4/indirect.c
@@ -652,13 +652,6 @@ int ext4_ind_map_blocks(handle_t *handle, struct inode *inode,
 	ext4_update_inode_fsync_trans(handle, inode, 1);
 	count = ar.len;
 
-	/*
-	 * Update reserved blocks/metadata blocks after successful block
-	 * allocation which had been deferred till now.
-	 */
-	if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
-		ext4_da_update_reserve_space(inode, count, 1);
-
 got_it:
 	map->m_flags |= EXT4_MAP_MAPPED;
 	map->m_pblk = le32_to_cpu(chain[depth-1].key);
-- 
2.31.1