2024-03-30 12:10:53

by Zhang Yi

[permalink] [raw]
Subject: [PATCH 1/7] ext4: trim delalloc extent

From: Zhang Yi <[email protected]>

The cached delalloc or hole extent should be trimed to the map->map_len
if we map delalloc blocks in ext4_da_map_blocks(). But it doesn't
trigger any issue now because the map->m_len is always set to one and we
always insert one delayed block once a time. Fix this by trim the extent
once we get one from the cached extent tree, prearing for mapping a
extent with multiple delalloc blocks.

Signed-off-by: Zhang Yi <[email protected]>
---
fs/ext4/inode.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 537803250ca9..b98f92622442 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1705,6 +1705,11 @@ static int ext4_da_map_blocks(struct inode *inode, sector_t iblock,

/* Lookup extent status tree firstly */
if (ext4_es_lookup_extent(inode, iblock, NULL, &es)) {
+ retval = es.es_len - (iblock - es.es_lblk);
+ if (retval > map->m_len)
+ retval = map->m_len;
+ map->m_len = retval;
+
if (ext4_es_is_hole(&es))
goto add_delayed;

@@ -1720,10 +1725,6 @@ static int ext4_da_map_blocks(struct inode *inode, sector_t iblock,
}

map->m_pblk = ext4_es_pblock(&es) + iblock - es.es_lblk;
- retval = es.es_len - (iblock - es.es_lblk);
- if (retval > map->m_len)
- retval = map->m_len;
- map->m_len = retval;
if (ext4_es_is_written(&es))
map->m_flags |= EXT4_MAP_MAPPED;
else if (ext4_es_is_unwritten(&es))
--
2.39.2