[PATCH v4 07/12] ext4: using nofail preallocation in ext4_es_insert_delayed_block()

Baokun Li
2023-04-24T03:40:04Z

Similar to in ext4_es_remove_extent(), we use a no-fail preallocation
to avoid inconsistencies, except that here we may have to preallocate
two extent_status.

Suggested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Baokun Li <libaokun1@huawei.com>
---
fs/ext4/extents_status.c | 33 ++++++++++++++++++++++-----------
1 file changed, 22 insertions(+), 11 deletions(-)

diff --git a/fs/ext4/extents_status.c b/fs/ext4/extents_status.c
index f4d50cd501fc..f892277155fa 100644
--- a/fs/ext4/extents_status.c
+++ b/fs/ext4/extents_status.c
@@ -2013,7 +2013,10 @@ int ext4_es_insert_delayed_block(struct inode *inode, ext4_lblk_t lblk,
bool allocated)
{
struct extent_status newes;
- int err = 0;
+ int err1 = 0;
+ int err2 = 0;
+ struct extent_status *es1 = NULL;
+ struct extent_status *es2 = NULL;

if (EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY)
return 0;
@@ -2028,29 +2031,37 @@ int ext4_es_insert_delayed_block(struct inode *inode, ext4_lblk_t lblk,

ext4_es_insert_extent_check(inode, &newes);

+retry:
+ if (err1 && !es1)
+ es1 = __es_alloc_extent(true);
+ if ((err1 || err2) && !es2)
+ es2 = __es_alloc_extent(true);
write_lock(&EXT4_I(inode)->i_es_lock);

- err = __es_remove_extent(inode, lblk, lblk, NULL, NULL);
- if (err != 0)
+ err1 = __es_remove_extent(inode, lblk, lblk, NULL, es1);
+ if (err1 != 0)
goto error;
-retry:
- err = __es_insert_extent(inode, &newes, NULL);
- if (err == -ENOMEM && __es_shrink(EXT4_SB(inode->i_sb),
- 128, EXT4_I(inode)))
- goto retry;
- if (err != 0)
+
+ err2 = __es_insert_extent(inode, &newes, es2);
+ if (err2 != 0)
goto error;

if (allocated)
__insert_pending(inode, lblk);

+ /* es is pre-allocated but not used, free it. */
+ if (es1 && !es1->es_len)
+ __es_free_extent(es1);
+ if (es2 && !es2->es_len)
+ __es_free_extent(es2);
error:
write_unlock(&EXT4_I(inode)->i_es_lock);
+ if (err1 || err2)
+ goto retry;

ext4_es_print_tree(inode);
ext4_print_pending_tree(inode);
-
- return err;
+ return 0;
}

/*
--
2.31.1