Re: [PATCH v3] ext4: Fix bug on in ext4_es_cache_extent as ext4_split_extent_at failed
From: Jan Kara <jack@suse.cz>
Date: 2021-05-06 10:19:20
Also in:
lkml
On Thu 06-05-21 16:26:24, yebin wrote:
quoted hunk ↗ jump to hunk
Thanks for your suggesttion. If you have no objection to following modification, i will send it as V4.diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index 77c84d6f1af6..f9cbd11e1eae 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c@@ -3206,7 +3206,10 @@ 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 && (EXT4_EXT_MAY_ZEROOUT & split_flag)) { + if (err != -ENOSPC && err != -EDQUOT) + goto out; + + if (EXT4_EXT_MAY_ZEROOUT & split_flag) {
You need: if (err && (EXT4_EXT_MAY_ZEROOUT & split_flag)) there, don't you? You don't want to zero-out if there's no error.
quoted hunk ↗ jump to hunk
@@ -3232,22 +3235,23 @@ static int ext4_split_extent_at(handle_t *handle,ext4_ext_pblock(&orig_ex)); } - if (err) - goto fix_extent_len; - /* update the extent length and mark as initialized */ - ex->ee_len = cpu_to_le16(ee_len); - ext4_ext_try_to_merge(handle, inode, path, ex); - err = ext4_ext_dirty(handle, inode, path + path->p_depth); - if (err) - goto fix_extent_len; - - /* update extent status tree */ - err = ext4_zeroout_es(inode, &zero_ex); - - goto out; - } else if (err) - goto fix_extent_len; - + if (!err) { + /* update the extent length and mark as initialized */ + ex->ee_len = cpu_to_le16(ee_len); + ext4_ext_try_to_merge(handle, inode, path, ex); + err = ext4_ext_dirty(handle, inode, path + path->p_depth); + if (!err) + /* update extent status tree */ + err = ext4_zeroout_es(inode, &zero_ex); + /* At here, ext4_ext_try_to_merge maybe already merge + * extent, if fix origin extent length may lead to + * overwritten. + */
I'd rephrase the comment as: /* * If we failed at this point, we don't know in which state the extent tree * exactly is so don't try to fix length of the original extent as it may do * even more damage. */
+ goto out; + } + } + if (err) + goto fix_extent_len;
And you can move this if (err) before if (!err) above to make code easier to read and save one indentation level.
out:
ext4_ext_show_leaf(inode, path);
return err;
Honza -- Jan Kara [off-list ref] SUSE Labs, CR