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); > .