[PATCH v2 6/6] ext4: fix insufficient credits calculation in ext4_meta_trans_blocks()

From: Zhang Yi
Date: Wed Jun 11 2025 - 07:32:07 EST


From: Zhang Yi <yi.zhang@xxxxxxxxxx>

The calculation of journal credits in ext4_meta_trans_blocks() should
include pextents, as each extent separately may be allocated from a
different group and thus need to update different bitmap and group
descriptor block.

Fixes: 0e32d8617012 ("ext4: correct the journal credits calculations of allocating blocks")
Reported-by: Jan Kara <jack@xxxxxxx>
Closes: https://lore.kernel.org/linux-ext4/nhxfuu53wyacsrq7xqgxvgzcggyscu2tbabginahcygvmc45hy@t4fvmyeky33e/
Signed-off-by: Zhang Yi <yi.zhang@xxxxxxxxxx>
Reviewed-by: Jan Kara <jack@xxxxxxx>
---
fs/ext4/inode.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 9835145b1b27..9b6ebf823740 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -6218,7 +6218,7 @@ int ext4_meta_trans_blocks(struct inode *inode, int lblocks, int pextents)
int ret;

/*
- * How many index and lead blocks need to touch to map @lblocks
+ * How many index and leaf blocks need to touch to map @lblocks
* logical blocks to @pextents physical extents?
*/
idxblocks = ext4_index_trans_blocks(inode, lblocks, pextents);
@@ -6227,7 +6227,7 @@ int ext4_meta_trans_blocks(struct inode *inode, int lblocks, int pextents)
* Now let's see how many group bitmaps and group descriptors need
* to account
*/
- groups = idxblocks;
+ groups = idxblocks + pextents;
gdpblocks = groups;
if (groups > ngroups)
groups = ngroups;
--
2.46.1