* Re: [PATCH v2] ext4: Make block validity check resistent to sb bh corruption
2025-03-27 17:48 [PATCH v2] ext4: Make block validity check resistent to sb bh corruption Ojaswin Mujoo
@ 2025-03-27 18:25 ` Jan Kara
2025-03-28 6:12 ` Ojaswin Mujoo
2025-03-28 1:52 ` Zhang Yi
2025-03-28 2:49 ` Baokun Li
2 siblings, 1 reply; 5+ messages in thread
From: Jan Kara @ 2025-03-27 18:25 UTC (permalink / raw)
To: Ojaswin Mujoo
Cc: linux-ext4, Theodore Ts'o, Jan Kara, Baokun Li,
Ritesh Harjani, Zhang Yi, linux-kernel
On Thu 27-03-25 23:18:09, Ojaswin Mujoo wrote:
> Block validity checks need to be skipped in case they are called
> for journal blocks since they are part of system's protected
> zone.
>
> Currently, this is done by checking inode->ino against
> sbi->s_es->s_journal_inum, which is a direct read from the ext4 sb
> buffer head. If someone modifies this underneath us then the
> s_journal_inum field might get corrupted. To prevent against this,
> change the check to directly compare the inode with journal->j_inode.
>
> **Slight change in behavior**: During journal init path,
> check_block_validity etc might be called for journal inode when
> sbi->s_journal is not set yet. In this case we now proceed with
> ext4_inode_block_valid() instead of returning early. Since systems zones
> have not been set yet, it is okay to proceed so we can perform basic
> checks on the blocks.
>
> Suggested-by: Baokun Li <libaokun1@huawei.com>
> Signed-off-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Looks good. Feel free to add:
Reviewed-by: Jan Kara <jack@suse.cz>
One style nit below:
> diff --git a/fs/ext4/block_validity.c b/fs/ext4/block_validity.c
> index 87ee3a17bd29..e8c5525afc67 100644
> --- a/fs/ext4/block_validity.c
> +++ b/fs/ext4/block_validity.c
> @@ -351,10 +351,9 @@ int ext4_check_blockref(const char *function, unsigned int line,
> {
> __le32 *bref = p;
> unsigned int blk;
> + journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
>
> - if (ext4_has_feature_journal(inode->i_sb) &&
> - (inode->i_ino ==
> - le32_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_journal_inum)))
> + if (journal && inode == journal->j_inode)
> return 0;
>
> while (bref < p+max) {
> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> index 365d31004bd0..8b048be14008 100644
> --- a/fs/ext4/inode.c
> +++ b/fs/ext4/inode.c
> @@ -384,10 +384,11 @@ static int __check_block_validity(struct inode *inode, const char *func,
> unsigned int line,
> struct ext4_map_blocks *map)
> {
> - if (ext4_has_feature_journal(inode->i_sb) &&
> - (inode->i_ino ==
> - le32_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_journal_inum)))
> - return 0;
> + journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
> +
> + if (journal && inode == journal->j_inode)
> + return 0;
Bogus indentation here.
Honza
--
Jan Kara <jack@suse.com>
SUSE Labs, CR
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH v2] ext4: Make block validity check resistent to sb bh corruption
2025-03-27 18:25 ` Jan Kara
@ 2025-03-28 6:12 ` Ojaswin Mujoo
0 siblings, 0 replies; 5+ messages in thread
From: Ojaswin Mujoo @ 2025-03-28 6:12 UTC (permalink / raw)
To: Jan Kara
Cc: linux-ext4, Theodore Ts'o, Baokun Li, Ritesh Harjani,
Zhang Yi, linux-kernel
On Thu, Mar 27, 2025 at 07:25:30PM +0100, Jan Kara wrote:
> On Thu 27-03-25 23:18:09, Ojaswin Mujoo wrote:
> > Block validity checks need to be skipped in case they are called
> > for journal blocks since they are part of system's protected
> > zone.
> >
> > Currently, this is done by checking inode->ino against
> > sbi->s_es->s_journal_inum, which is a direct read from the ext4 sb
> > buffer head. If someone modifies this underneath us then the
> > s_journal_inum field might get corrupted. To prevent against this,
> > change the check to directly compare the inode with journal->j_inode.
> >
> > **Slight change in behavior**: During journal init path,
> > check_block_validity etc might be called for journal inode when
> > sbi->s_journal is not set yet. In this case we now proceed with
> > ext4_inode_block_valid() instead of returning early. Since systems zones
> > have not been set yet, it is okay to proceed so we can perform basic
> > checks on the blocks.
> >
> > Suggested-by: Baokun Li <libaokun1@huawei.com>
> > Signed-off-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
>
> Looks good. Feel free to add:
>
> Reviewed-by: Jan Kara <jack@suse.cz>
>
> One style nit below:
>
> > diff --git a/fs/ext4/block_validity.c b/fs/ext4/block_validity.c
> > index 87ee3a17bd29..e8c5525afc67 100644
> > --- a/fs/ext4/block_validity.c
> > +++ b/fs/ext4/block_validity.c
> > @@ -351,10 +351,9 @@ int ext4_check_blockref(const char *function, unsigned int line,
> > {
> > __le32 *bref = p;
> > unsigned int blk;
> > + journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
> >
> > - if (ext4_has_feature_journal(inode->i_sb) &&
> > - (inode->i_ino ==
> > - le32_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_journal_inum)))
> > + if (journal && inode == journal->j_inode)
> > return 0;
> >
> > while (bref < p+max) {
> > diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> > index 365d31004bd0..8b048be14008 100644
> > --- a/fs/ext4/inode.c
> > +++ b/fs/ext4/inode.c
> > @@ -384,10 +384,11 @@ static int __check_block_validity(struct inode *inode, const char *func,
> > unsigned int line,
> > struct ext4_map_blocks *map)
> > {
> > - if (ext4_has_feature_journal(inode->i_sb) &&
> > - (inode->i_ino ==
> > - le32_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_journal_inum)))
> > - return 0;
> > + journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
> > +
> > + if (journal && inode == journal->j_inode)
> > + return 0;
>
> Bogus indentation here.
Thanks for the review Jan and for catching this. My bad, i missed
running checkpatch on this and somehow this looked okay in vim.
I'll fix this and quickly send a v3.
Regards,
ojaswin
>
> Honza
> --
> Jan Kara <jack@suse.com>
> SUSE Labs, CR
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v2] ext4: Make block validity check resistent to sb bh corruption
2025-03-27 17:48 [PATCH v2] ext4: Make block validity check resistent to sb bh corruption Ojaswin Mujoo
2025-03-27 18:25 ` Jan Kara
@ 2025-03-28 1:52 ` Zhang Yi
2025-03-28 2:49 ` Baokun Li
2 siblings, 0 replies; 5+ messages in thread
From: Zhang Yi @ 2025-03-28 1:52 UTC (permalink / raw)
To: Ojaswin Mujoo
Cc: Jan Kara, Baokun Li, Ritesh Harjani, linux-kernel, linux-ext4,
Theodore Ts'o
On 2025/3/28 1:48, Ojaswin Mujoo wrote:
> Block validity checks need to be skipped in case they are called
> for journal blocks since they are part of system's protected
> zone.
>
> Currently, this is done by checking inode->ino against
> sbi->s_es->s_journal_inum, which is a direct read from the ext4 sb
> buffer head. If someone modifies this underneath us then the
> s_journal_inum field might get corrupted. To prevent against this,
> change the check to directly compare the inode with journal->j_inode.
>
> **Slight change in behavior**: During journal init path,
> check_block_validity etc might be called for journal inode when
> sbi->s_journal is not set yet. In this case we now proceed with
> ext4_inode_block_valid() instead of returning early. Since systems zones
> have not been set yet, it is okay to proceed so we can perform basic
> checks on the blocks.
>
> Suggested-by: Baokun Li <libaokun1@huawei.com>
> Signed-off-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Thanks for the inprovement! Besides the indentation that Jan pointed
out, it looks good to me.
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
> ---
>
> ** Changes since v1 [1] **
>
> - instead of using an sbi field direction check against jorunal->j_inode
> - let block validity perform basic checks on journal blocks as well
> during init path
> - kvm-xfstests quick tests are passing
>
> [1] https://lore.kernel.org/linux-ext4/d1a9328a41029f6210a1924b192a59afcd3c5cee.1741952406.git.ojaswin@linux.ibm.com/
>
> fs/ext4/block_validity.c | 5 ++---
> fs/ext4/inode.c | 9 +++++----
> 2 files changed, 7 insertions(+), 7 deletions(-)
>
> diff --git a/fs/ext4/block_validity.c b/fs/ext4/block_validity.c
> index 87ee3a17bd29..e8c5525afc67 100644
> --- a/fs/ext4/block_validity.c
> +++ b/fs/ext4/block_validity.c
> @@ -351,10 +351,9 @@ int ext4_check_blockref(const char *function, unsigned int line,
> {
> __le32 *bref = p;
> unsigned int blk;
> + journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
>
> - if (ext4_has_feature_journal(inode->i_sb) &&
> - (inode->i_ino ==
> - le32_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_journal_inum)))
> + if (journal && inode == journal->j_inode)
> return 0;
>
> while (bref < p+max) {
> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> index 365d31004bd0..8b048be14008 100644
> --- a/fs/ext4/inode.c
> +++ b/fs/ext4/inode.c
> @@ -384,10 +384,11 @@ static int __check_block_validity(struct inode *inode, const char *func,
> unsigned int line,
> struct ext4_map_blocks *map)
> {
> - if (ext4_has_feature_journal(inode->i_sb) &&
> - (inode->i_ino ==
> - le32_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_journal_inum)))
> - return 0;
> + journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
> +
> + if (journal && inode == journal->j_inode)
> + return 0;
> +
> if (!ext4_inode_block_valid(inode, map->m_pblk, map->m_len)) {
> ext4_error_inode(inode, func, line, map->m_pblk,
> "lblock %lu mapped to illegal pblock %llu "
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH v2] ext4: Make block validity check resistent to sb bh corruption
2025-03-27 17:48 [PATCH v2] ext4: Make block validity check resistent to sb bh corruption Ojaswin Mujoo
2025-03-27 18:25 ` Jan Kara
2025-03-28 1:52 ` Zhang Yi
@ 2025-03-28 2:49 ` Baokun Li
2 siblings, 0 replies; 5+ messages in thread
From: Baokun Li @ 2025-03-28 2:49 UTC (permalink / raw)
To: Ojaswin Mujoo
Cc: Theodore Ts'o, Jan Kara, Ritesh Harjani, Zhang Yi,
linux-kernel, linux-ext4, Yang Erkun
On 2025/3/28 1:48, Ojaswin Mujoo wrote:
> Block validity checks need to be skipped in case they are called
> for journal blocks since they are part of system's protected
> zone.
>
> Currently, this is done by checking inode->ino against
> sbi->s_es->s_journal_inum, which is a direct read from the ext4 sb
> buffer head. If someone modifies this underneath us then the
> s_journal_inum field might get corrupted. To prevent against this,
> change the check to directly compare the inode with journal->j_inode.
>
> **Slight change in behavior**: During journal init path,
> check_block_validity etc might be called for journal inode when
> sbi->s_journal is not set yet. In this case we now proceed with
> ext4_inode_block_valid() instead of returning early. Since systems zones
> have not been set yet, it is okay to proceed so we can perform basic
> checks on the blocks.
>
> Suggested-by: Baokun Li <libaokun1@huawei.com>
> Signed-off-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Thanks for the patch！Looks good to me, except for the extra indentation
pointed out by Honza. With that fixed feel free to add:
Reviewed-by: Baokun Li <libaokun1@huawei.com>
Cheers,
Baokun
> ---
>
> ** Changes since v1 [1] **
>
> - instead of using an sbi field direction check against jorunal->j_inode
> - let block validity perform basic checks on journal blocks as well
> during init path
> - kvm-xfstests quick tests are passing
>
> [1] https://lore.kernel.org/linux-ext4/d1a9328a41029f6210a1924b192a59afcd3c5cee.1741952406.git.ojaswin@linux.ibm.com/
>
> fs/ext4/block_validity.c | 5 ++---
> fs/ext4/inode.c | 9 +++++----
> 2 files changed, 7 insertions(+), 7 deletions(-)
>
> diff --git a/fs/ext4/block_validity.c b/fs/ext4/block_validity.c
> index 87ee3a17bd29..e8c5525afc67 100644
> --- a/fs/ext4/block_validity.c
> +++ b/fs/ext4/block_validity.c
> @@ -351,10 +351,9 @@ int ext4_check_blockref(const char *function, unsigned int line,
> {
> __le32 *bref = p;
> unsigned int blk;
> + journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
>
> - if (ext4_has_feature_journal(inode->i_sb) &&
> - (inode->i_ino ==
> - le32_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_journal_inum)))
> + if (journal && inode == journal->j_inode)
> return 0;
>
> while (bref < p+max) {
> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> index 365d31004bd0..8b048be14008 100644
> --- a/fs/ext4/inode.c
> +++ b/fs/ext4/inode.c
> @@ -384,10 +384,11 @@ static int __check_block_validity(struct inode *inode, const char *func,
> unsigned int line,
> struct ext4_map_blocks *map)
> {
> - if (ext4_has_feature_journal(inode->i_sb) &&
> - (inode->i_ino ==
> - le32_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_journal_inum)))
> - return 0;
> + journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
> +
> + if (journal && inode == journal->j_inode)
> + return 0;
> +
> if (!ext4_inode_block_valid(inode, map->m_pblk, map->m_len)) {
> ext4_error_inode(inode, func, line, map->m_pblk,
> "lblock %lu mapped to illegal pblock %llu "
^ permalink raw reply [flat|nested] 5+ messages in thread