From a30eec2a8650a77f754e84b2e15f062fe652baa7 Mon Sep 17 00:00:00 2001
From: Eric Sandeen <sandeen@redhat.com>
Date: Sun, 16 May 2010 03:00:00 -0400
Subject: [PATCH] ext4: stop issuing discards if not supported by device
Turn off issuance of discard requests if the device does
not support it - similar to the action we take for barriers.
This will save a little computation time if a non-discardable
device is mounted with -o discard, and also makes it obvious
that it's not doing what was asked at mount time ...
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
---
fs/ext4/mballoc.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 8639d5a637b2..4f2d3a9d4e21 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -2534,6 +2534,7 @@ static void release_blocks_on_commit(journal_t *journal, transaction_t *txn)
entry->count, entry->group, entry);
if (test_opt(sb, DISCARD)) {
+ int ret;
ext4_fsblk_t discard_block;
discard_block = entry->start_blk +
@@ -2541,7 +2542,12 @@ static void release_blocks_on_commit(journal_t *journal, transaction_t *txn)
trace_ext4_discard_blocks(sb,
(unsigned long long)discard_block,
entry->count);
- sb_issue_discard(sb, 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);
+ }
}
err = ext4_mb_load_buddy(sb, entry->group, &e4b);
--
2.50.1