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ext4: Fix memory leak in ext4_init_new_dir

PATCH In review Mel Gorman 2 participants 3 messages Jan 11, 2013 ext4 file system

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Mel Gorman

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#0 lore raw

PATCH 1/1 ext4: Fix memory leak in ext4_init_new_dir

Commit a774f9c2 "ext4: make ext4_init_dot_dotdot for inline dir usage" is a preparation cleanup for later ext4 patches but there was a snag when moving code to the newly created ext4_init_new_dir() function. ext4_bread() is called twice but brelse() is only called one leading to a memory leak. The user-visible effect is that after a compile-orientated benchmark 0% of memory could be allocated as transparent huge pages. This patch deletes the extra call and after it is applied, 76% of memory could be allocated after the same test.

---
 fs/ext4/namei.c |    1 -
 1 file changed, 1 deletion(-)
fs/ext4/namei.c +0 -1
index 8990165..d068885 100644
@@ -2368,7 +2368,6 @@ static int ext4_init_new_dir(handle_t *handle, struct inode *dir,
 	}
 
 	inode->i_size = EXT4_I(inode)->i_disksize = blocksize;
-	dir_block = ext4_bread(handle, inode, 0, 1, &err);
 	if (!(dir_block = ext4_bread(handle, inode, 0, 1, &err))) {
 		if (!err) {
 			err = -EIO;
#1 lore raw

Hi Mel,

Thanks for the report.

This bug is already spotted by Guo Chao and the patch has been accepted by Ted already.

Thanks,
Tao

Quoted 32 lines · Mel Gorman

Commit a774f9c2 "ext4: make ext4_init_dot_dotdot for inline dir usage" is a preparation cleanup for later ext4 patches but there was a snag when moving code to the newly created ext4_init_new_dir() function. ext4_bread() is called twice but brelse() is only called one leading to a memory leak. The user-visible effect is that after a compile-orientated benchmark 0% of memory could be allocated as transparent huge pages. This patch deletes the extra call and after it is applied, 76% of memory could be allocated after the same test.

---
 fs/ext4/namei.c |    1 -
 1 file changed, 1 deletion(-)
fs/ext4/namei.c +0 -2
index 8990165..d068885 100644
@@ -2368,7 +2368,6 @@ static int ext4_init_new_dir(handle_t *handle, struct inode *dir,
 	}
 
 	inode->i_size = EXT4_I(inode)->i_disksize = blocksize;
-	dir_block = ext4_bread(handle, inode, 0, 1, &err);
 	if (!(dir_block = ext4_bread(handle, inode, 0, 1, &err))) {
 		if (!err) {
 			err = -EIO;
--

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author
#2 lore raw
Quoted 7 lines · Tao Ma

Hi Mel,

Thanks for the report.

This bug is already spotted by Guo Chao and the patch has been accepted by Ted already.

Ah grand, I see now that it was merged for 3.8-rc3. Thanks for the heads up.

Signature · 2 lines
Mel Gorman
SUSE Labs