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>

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 84185d2..5338b1c 100644 (file)
--- 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;