Sorry Hou for getting back to you late. This looks good to me.
Reviewed-by: Harshad Shirwadkar <harshadshirwadkar@xxxxxxxxx>
On Tue, Sep 7, 2021 at 4:21 AM Hou Tao <houtao1@xxxxxxxxxx> wrote:
>
> ping ?
>
> On 8/30/2021 3:52 PM, Hou Tao wrote:
> > ping ?
> >
> > On 8/20/2021 12:45 PM, Hou Tao wrote:
> >> Now EXT4_FC_TAG_ADD_RANGE uses ext4_extent to track the
> >> newly-added blocks, but the limit on the max value of
> >> ee_len field is ignored, and it can lead to BUG_ON as
> >> shown below when running command "fallocate -l 128M file"
> >> on a fast_commit-enabled fs:
> >>
> >> kernel BUG at fs/ext4/ext4_extents.h:199!
> >> invalid opcode: 0000 [#1] SMP PTI
> >> CPU: 3 PID: 624 Comm: fallocate Not tainted 5.14.0-rc6+ #1
> >> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996)
> >> RIP: 0010:ext4_fc_write_inode_data+0x1f3/0x200
> >> Call Trace:
> >> ? ext4_fc_write_inode+0xf2/0x150
> >> ext4_fc_commit+0x93b/0xa00
> >> ? ext4_fallocate+0x1ad/0x10d0
> >> ext4_sync_file+0x157/0x340
> >> ? ext4_sync_file+0x157/0x340
> >> vfs_fsync_range+0x49/0x80
> >> do_fsync+0x3d/0x70
> >> __x64_sys_fsync+0x14/0x20
> >> do_syscall_64+0x3b/0xc0
> >> entry_SYSCALL_64_after_hwframe+0x44/0xae
> >>
> >> Simply fixing it by limiting the number of blocks
> >> in one EXT4_FC_TAG_ADD_RANGE TLV.
> >>
> >> Fixes: aa75f4d3daae ("ext4: main fast-commit commit path")
> >> Signed-off-by: Hou Tao <houtao1@xxxxxxxxxx>
> >> ---
> >> fs/ext4/fast_commit.c | 6 ++++++
> >> 1 file changed, 6 insertions(+)
> >>
> >> diff --git a/fs/ext4/fast_commit.c b/fs/ext4/fast_commit.c
> >> index e8195229c252..782d05a3f97a 100644
> >> --- a/fs/ext4/fast_commit.c
> >> +++ b/fs/ext4/fast_commit.c
> >> @@ -893,6 +893,12 @@ static int ext4_fc_write_inode_data(struct inode *inode, u32 *crc)
> >> sizeof(lrange), (u8 *)&lrange, crc))
> >> return -ENOSPC;
> >> } else {
> >> + unsigned int max = (map.m_flags & EXT4_MAP_UNWRITTEN) ?
> >> + EXT_UNWRITTEN_MAX_LEN : EXT_INIT_MAX_LEN;
> >> +
> >> + /* Limit the number of blocks in one extent */
> >> + map.m_len = min(max, map.m_len);
> >> +
> >> fc_ext.fc_ino = cpu_to_le32(inode->i_ino);
> >> ex = (struct ext4_extent *)&fc_ext.fc_ex;
> >> ex->ee_block = cpu_to_le32(map.m_lblk);
> > .
