ext4: Support discard requests when running in no-journal mode

Issue discard request in ext4_free_blocks() when ext4 has no journal and
is mounted with discard option.
    
Signed-off-by: Jiaying Zhang <jiayingz@google.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

1 files changed, 21 insertions, 16 deletions

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 84185d215004..5338b1ca64bb 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -2558,6 +2558,22 @@ int ext4_mb_release(struct super_block *sb)
         return 0;
 }
 
+static inline void ext4_issue_discard(struct super_block *sb,
+                ext4_group_t block_group, ext4_grpblk_t block, int count)
+{
+        int ret;
+        ext4_fsblk_t discard_block;
+
+        discard_block = block + ext4_group_first_block_no(sb, block_group);
+        trace_ext4_discard_blocks(sb,
+                        (unsigned long long) discard_block, count);
+        ret = sb_issue_discard(sb, discard_block, count);
+        if (ret == EOPNOTSUPP) {
+                ext4_warning(sb, "discard not supported, disabling");
+                clear_opt(EXT4_SB(sb)->s_mount_opt, DISCARD);
+        }
+}
+
 /*
  * This function is called by the jbd2 layer once the commit has finished,
  * so we know we can free the blocks that were released with that commit.
@@ -2577,22 +2593,9 @@ static void release_blocks_on_commit(journal_t *journal, transaction_t *txn)
                 mb_debug(1, "gonna free %u blocks in group %u (0x%p):",
                          entry->count, entry->group, entry);
 
-                if (test_opt(sb, DISCARD)) {
-                        int ret;
-                        ext4_fsblk_t discard_block;
-
-                        discard_block = entry->start_blk +
-                                ext4_group_first_block_no(sb, entry->group);
-                        trace_ext4_discard_blocks(sb,
-                                        (unsigned long long)discard_block,
-                                        entry->count);
-                        ret = sb_issue_discard(sb, discard_block, entry->count);
-                        if (ret == EOPNOTSUPP) {
-                                ext4_warning(sb,
-                                        "discard not supported, disabling");
-                                clear_opt(EXT4_SB(sb)->s_mount_opt, DISCARD);
-                        }
-                }
+                if (test_opt(sb, DISCARD))
+                        ext4_issue_discard(sb, entry->group,
+                                        entry->start_blk, entry->count);
 
                 err = ext4_mb_load_buddy(sb, entry->group, &e4b);
                 /* we expect to find existing buddy because it's pinned */
@@ -4639,6 +4642,8 @@ do_more:
                 mb_clear_bits(bitmap_bh->b_data, bit, count);
                 mb_free_blocks(inode, &e4b, bit, count);
                 ext4_mb_return_to_preallocation(inode, &e4b, block, count);
+                if (test_opt(sb, DISCARD))
+                        ext4_issue_discard(sb, block_group, bit, count);
         }
 
         ret = ext4_free_blks_count(sb, gdp) + count;