[PATCH v4 08/12] ext4: using nofail preallocation in ext4_es_insert_extent()

Baokun Li
2023-04-24T03:40:06Z

Similar to in ext4_es_insert_delayed_block(), we use preallocations that
do not fail to avoid inconsistencies, but we do not care about es that are
not must be kept, and we return 0 even if such es memory allocation fails.

Suggested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Baokun Li <libaokun1@huawei.com>
---
fs/ext4/extents_status.c | 38 ++++++++++++++++++++++++++------------
1 file changed, 26 insertions(+), 12 deletions(-)

diff --git a/fs/ext4/extents_status.c b/fs/ext4/extents_status.c
index f892277155fa..91828cf7395b 100644
--- a/fs/ext4/extents_status.c
+++ b/fs/ext4/extents_status.c
@@ -840,8 +840,11 @@ int ext4_es_insert_extent(struct inode *inode, ext4_lblk_t lblk,
{
struct extent_status newes;
ext4_lblk_t end = lblk + len - 1;
- int err = 0;
+ int err1 = 0;
+ int err2 = 0;
struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+ struct extent_status *es1 = NULL;
+ struct extent_status *es2 = NULL;

if (EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY)
return 0;
@@ -869,29 +872,40 @@ int ext4_es_insert_extent(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, end, NULL, NULL);
- if (err != 0)
+
+ err1 = __es_remove_extent(inode, lblk, end, NULL, es1);
+ if (err1 != 0)
+ goto error;
+
+ err2 = __es_insert_extent(inode, &newes, es2);
+ if (err2 == -ENOMEM && !ext4_es_must_keep(&newes))
+ err2 = 0;
+ if (err2 != 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 == -ENOMEM && !ext4_es_must_keep(&newes))
- err = 0;

if (sbi->s_cluster_ratio > 1 && test_opt(inode->i_sb, DELALLOC) &&
(status & EXTENT_STATUS_WRITTEN ||
status & EXTENT_STATUS_UNWRITTEN))
__revise_pending(inode, lblk, len);

+ /* 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);
-
- return err;
+ return 0;
}

/*
--
2.31.1