2023-02-13 07:41:38

by zhanchengbin

[permalink] [raw]
Subject: [PATCH v5 1/2] ext4: fix inode tree inconsistency caused by ENOMEM in ext4_split_extent_at

If ENOMEM fails when the extent is splitting, we need to restore the length
of the split extent.
In the call stack of the ext4_split_extent_at function, only in
ext4_ext_create_new_leaf will it alloc memory and change the shape of the
extent tree,even if an ENOMEM is returned at this time, the extent tree is
still self-consistent, Just restore the split extent lens in the function
ext4_split_extent_at.

ext4_split_extent_at
ext4_ext_insert_extent
ext4_ext_create_new_leaf
1)ext4_ext_split
ext4_find_extent
2)ext4_ext_grow_indepth
ext4_find_extent

Signed-off-by: zhanchengbin <[email protected]>
---
fs/ext4/extents.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 9de1c9d1a13d..0f95e857089e 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -935,6 +935,7 @@ ext4_find_extent(struct inode *inode, ext4_lblk_t block,

bh = read_extent_tree_block(inode, path[ppos].p_idx, --i, flags);
if (IS_ERR(bh)) {
+ EXT4_ERROR_INODE(inode, "IO error reading extent block");
ret = PTR_ERR(bh);
goto err;
}
@@ -3251,7 +3252,7 @@ static int ext4_split_extent_at(handle_t *handle,
ext4_ext_mark_unwritten(ex2);

err = ext4_ext_insert_extent(handle, inode, ppath, &newex, flags);
- if (err != -ENOSPC && err != -EDQUOT)
+ if (err != -ENOSPC && err != -EDQUOT && err != -ENOMEM)
goto out;

if (EXT4_EXT_MAY_ZEROOUT & split_flag) {
--
2.31.1