2021-06-29 14:49:55

by Desmond Cheong Zhi Xi

[permalink] [raw]
Subject: [PATCH 1/3] hfs: add missing clean-up in hfs_fill_super

On exiting hfs_fill_super, the file descriptor used in hfs_find_init
should be passed to hfs_find_exit to be cleaned up, and to release the
lock held on the btree.

The call to hfs_find_exit is missing from this error path, so we add
it in to release resources.

Signed-off-by: Desmond Cheong Zhi Xi <[email protected]>
---
fs/hfs/super.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/fs/hfs/super.c b/fs/hfs/super.c
index 44d07c9e3a7f..48340b77eb36 100644
--- a/fs/hfs/super.c
+++ b/fs/hfs/super.c
@@ -419,6 +419,7 @@ static int hfs_fill_super(struct super_block *sb, void *data, int silent)
res = hfs_cat_find_brec(sb, HFS_ROOT_CNID, &fd);
if (!res) {
if (fd.entrylength > sizeof(rec) || fd.entrylength < 0) {
+ hfs_find_exit(&fd);
res = -EIO;
goto bail;
}
--
2.25.1


2021-06-29 19:19:48

by Viacheslav Dubeyko

[permalink] [raw]
Subject: Re: [PATCH 1/3] hfs: add missing clean-up in hfs_fill_super



> On Jun 29, 2021, at 7:48 AM, Desmond Cheong Zhi Xi <[email protected]> wrote:
>
> On exiting hfs_fill_super, the file descriptor used in hfs_find_init
> should be passed to hfs_find_exit to be cleaned up, and to release the
> lock held on the btree.
>
> The call to hfs_find_exit is missing from this error path, so we add
> it in to release resources.
>
> Signed-off-by: Desmond Cheong Zhi Xi <[email protected]>
> ---
> fs/hfs/super.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/fs/hfs/super.c b/fs/hfs/super.c
> index 44d07c9e3a7f..48340b77eb36 100644
> --- a/fs/hfs/super.c
> +++ b/fs/hfs/super.c
> @@ -419,6 +419,7 @@ static int hfs_fill_super(struct super_block *sb, void *data, int silent)
> res = hfs_cat_find_brec(sb, HFS_ROOT_CNID, &fd);
> if (!res) {
> if (fd.entrylength > sizeof(rec) || fd.entrylength < 0) {
> + hfs_find_exit(&fd);

I see that there are several places of hfs_find_exit() calls in hfs_fill_super(). Maybe, it makes sense to move the hfs_find_exit() call to the end of the hfs_fill_super()? In this case we could process this activity of resources freeing into one place. I mean line 449 in the source code (failure case).

Thanks,
Slava.

> res = -EIO;
> goto bail;
> }
> --
> 2.25.1
>

2021-06-30 05:10:51

by Desmond Cheong Zhi Xi

[permalink] [raw]
Subject: Re: [PATCH 1/3] hfs: add missing clean-up in hfs_fill_super

On 30/6/21 3:13 am, Viacheslav Dubeyko wrote:
>
>
>> On Jun 29, 2021, at 7:48 AM, Desmond Cheong Zhi Xi <[email protected]> wrote:
>>
>> On exiting hfs_fill_super, the file descriptor used in hfs_find_init
>> should be passed to hfs_find_exit to be cleaned up, and to release the
>> lock held on the btree.
>>
>> The call to hfs_find_exit is missing from this error path, so we add
>> it in to release resources.
>>
>> Signed-off-by: Desmond Cheong Zhi Xi <[email protected]>
>> ---
>> fs/hfs/super.c | 1 +
>> 1 file changed, 1 insertion(+)
>>
>> diff --git a/fs/hfs/super.c b/fs/hfs/super.c
>> index 44d07c9e3a7f..48340b77eb36 100644
>> --- a/fs/hfs/super.c
>> +++ b/fs/hfs/super.c
>> @@ -419,6 +419,7 @@ static int hfs_fill_super(struct super_block *sb, void *data, int silent)
>> res = hfs_cat_find_brec(sb, HFS_ROOT_CNID, &fd);
>> if (!res) {
>> if (fd.entrylength > sizeof(rec) || fd.entrylength < 0) {
>> + hfs_find_exit(&fd);
>
> I see that there are several places of hfs_find_exit() calls in hfs_fill_super(). Maybe, it makes sense to move the hfs_find_exit() call to the end of the hfs_fill_super()? In this case we could process this activity of resources freeing into one place. I mean line 449 in the source code (failure case).
>
> Thanks,
> Slava.
>
>> res = -EIO;
>> goto bail;
>> }
>> --
>> 2.25.1
>>
>

Thanks for the suggestion. Since the bail and bail_no_root error paths
are used before hfs_find_init and after hfs_find_exit are called in the
normal execution case, moving hfs_find_exit under the bail label
wouldn't work.

Perhaps this can be done by introducing another goto label. Any thoughts
on the following?

diff --git a/fs/hfs/super.c b/fs/hfs/super.c
index 44d07c9e3a7f..12d9bae39363 100644
--- a/fs/hfs/super.c
+++ b/fs/hfs/super.c
@@ -420,14 +420,12 @@ static int hfs_fill_super(struct super_block *sb,
void *data, int silent)
if (!res) {
if (fd.entrylength > sizeof(rec) || fd.entrylength < 0) {
res = -EIO;
- goto bail;
+ goto bail_hfs_find;
}
hfs_bnode_read(fd.bnode, &rec, fd.entryoffset,
fd.entrylength);
}
- if (res) {
- hfs_find_exit(&fd);
- goto bail_no_root;
- }
+ if (res)
+ goto bail_hfs_find;
res = -EINVAL;
root_inode = hfs_iget(sb, &fd.search_key->cat, &rec);
hfs_find_exit(&fd);
@@ -443,6 +441,8 @@ static int hfs_fill_super(struct super_block *sb,
void *data, int silent)
/* everything's okay */
return 0;

+bail_hfs_find:
+ hfs_find_exit(&fd);
bail_no_root:
pr_err("get root inode failed\n");
bail:

2021-06-30 16:51:54

by Viacheslav Dubeyko

[permalink] [raw]
Subject: Re: [PATCH 1/3] hfs: add missing clean-up in hfs_fill_super



> On Jun 29, 2021, at 9:50 PM, Desmond Cheong Zhi Xi <[email protected]> wrote:

<skipped>

> Thanks for the suggestion. Since the bail and bail_no_root error paths are used before hfs_find_init and after hfs_find_exit are called in the normal execution case, moving hfs_find_exit under the bail label wouldn't work.
>
> Perhaps this can be done by introducing another goto label. Any thoughts on the following?
>
> diff --git a/fs/hfs/super.c b/fs/hfs/super.c
> index 44d07c9e3a7f..12d9bae39363 100644
> --- a/fs/hfs/super.c
> +++ b/fs/hfs/super.c
> @@ -420,14 +420,12 @@ static int hfs_fill_super(struct super_block *sb, void *data, int silent)
> if (!res) {
> if (fd.entrylength > sizeof(rec) || fd.entrylength < 0) {
> res = -EIO;
> - goto bail;
> + goto bail_hfs_find;
> }
> hfs_bnode_read(fd.bnode, &rec, fd.entryoffset, fd.entrylength);
> }
> - if (res) {
> - hfs_find_exit(&fd);
> - goto bail_no_root;
> - }
> + if (res)
> + goto bail_hfs_find;
> res = -EINVAL;
> root_inode = hfs_iget(sb, &fd.search_key->cat, &rec);
> hfs_find_exit(&fd);
> @@ -443,6 +441,8 @@ static int hfs_fill_super(struct super_block *sb, void *data, int silent)
> /* everything's okay */
> return 0;
>
> +bail_hfs_find:
> + hfs_find_exit(&fd);
> bail_no_root:
> pr_err("get root inode failed\n");
> bail:

Makes sense. Looks good.

Thanks,
Slava.