ext4: fix loop in do_split()
PATCH 1/1 ext4: fix loop in do_split()
unsigned i >= 0 is always true
Signed-off-by Roel Kluin <[email protected]>
---
fs/ext4/namei.c +1 -1
@@ -1198,7 +1198,7 @@ static struct ext4_dir_entry_2 *do_split(handle_t *handle, struct inode *dir,/* Split the existing block in the middle, size-wise */ size =0 ; move =0 ; -for (i = count-1 ; i >=0 ; i--) { +for (i = count-1 ; i < count; i--) {/* is more than half of this entry in 2nd half of the block? */ if (size + map[i].size/2 > blocksize/2 )break ;
Quoted 10 lines · roel kluin
unsigned i >= 0 is always true
Signed-off-by Roel Kluin <[email protected]>---
fs/ext4/namei.c +0
-0
fs/ext4/namei.c static struct ext4_dir_entry_2 *do_split(handle_t *handle, struct inode *dir, · line 1204
Quoted 8 lines
fs/ext4/namei.c +1
-1@@ -1198,7 +1198,7 @@ static struct ext4_dir_entry_2 *do_split(handle_t *handle, struct inode *dir,/* Split the existing block in the middle, size-wise */ size =0 ; move =0 ; -for (i = count-1 ; i >=0 ; i--) { +for (i = count-1 ; i < count; i--) {/* is more than half of this entry in 2nd half of the block? */ if (size + map[i].size/2 > blocksize/2 )break ;
While this unsigned wrap method is technically valid, it certainly isn't obvious, and making code readable should be a goal as well as making it correct.
After all, code which is hard to read is hard to understand, making it hard to
maintain. I therefore suggest the simpler form:
for (i = count; i--; ) {which gives the same i values inside the loop, but does assume that the reader remembers that i is unsigned, and intuitively understand wraparound while passing zero.
Signature · 3 lines
Bill Davidsen <[email protected]> "We have more to fear from the bungling of the incompetent than from the machinations of the wicked." - from Slashdot