From: Chao Yu chao@kernel.org

[ Upstream commit 298b1e4182d657c3e388adcc29477904e9600ed5 ]

chenyuwen reports a f2fs bug as below:

Unable to handle kernel NULL pointer dereference at virtual address 0000000000000011 fscrypt_set_bio_crypt_ctx+0x78/0x1e8 f2fs_grab_read_bio+0x78/0x208 f2fs_submit_page_read+0x44/0x154 f2fs_get_read_data_page+0x288/0x5f4 f2fs_get_lock_data_page+0x60/0x190 truncate_partial_data_page+0x108/0x4fc f2fs_do_truncate_blocks+0x344/0x5f0 f2fs_truncate_blocks+0x6c/0x134 f2fs_truncate+0xd8/0x200 f2fs_iget+0x20c/0x5ac do_garbage_collect+0x5d0/0xf6c f2fs_gc+0x22c/0x6a4 f2fs_disable_checkpoint+0xc8/0x310 f2fs_fill_super+0x14bc/0x1764 mount_bdev+0x1b4/0x21c f2fs_mount+0x20/0x30 legacy_get_tree+0x50/0xbc vfs_get_tree+0x5c/0x1b0 do_new_mount+0x298/0x4cc path_mount+0x33c/0x5fc __arm64_sys_mount+0xcc/0x15c invoke_syscall+0x60/0x150 el0_svc_common+0xb8/0xf8 do_el0_svc+0x28/0xa0 el0_svc+0x24/0x84 el0t_64_sync_handler+0x88/0xec

It is because inode.i_crypt_info is not initialized during below path: - mount - f2fs_fill_super - f2fs_disable_checkpoint - f2fs_gc - f2fs_iget - f2fs_truncate

So, let's relocate truncation of preallocated blocks to f2fs_file_open(), after fscrypt_file_open().

Fixes: d4dd19ec1ea0 ("f2fs: do not expose unwritten blocks to user by DIO") Reported-by: chenyuwen yuwen.chen@xjmz.com Closes: https://lore.kernel.org/linux-kernel/20240517085327.1188515-1-yuwen.chen@xjm... Signed-off-by: Chao Yu chao@kernel.org Signed-off-by: Jaegeuk Kim jaegeuk@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Shivani Agarwal shivani.agarwal@broadcom.com --- fs/f2fs/f2fs.h | 1 + fs/f2fs/file.c | 42 +++++++++++++++++++++++++++++++++++++++++- fs/f2fs/inode.c | 8 -------- 3 files changed, 42 insertions(+), 9 deletions(-)

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h index a02c74875..2b540d878 100644 --- a/fs/f2fs/f2fs.h +++ b/fs/f2fs/f2fs.h @@ -788,6 +788,7 @@ enum { FI_ALIGNED_WRITE, /* enable aligned write */ FI_COW_FILE, /* indicate COW file */ FI_ATOMIC_COMMITTED, /* indicate atomic commit completed except disk sync */ + FI_OPENED_FILE, /* indicate file has been opened */ FI_MAX, /* max flag, never be used */ };

diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c index c6fb179f9..62f2521cd 100644 --- a/fs/f2fs/file.c +++ b/fs/f2fs/file.c @@ -538,6 +538,42 @@ static int f2fs_file_mmap(struct file *file, struct vm_area_struct *vma) return 0; }

+static int finish_preallocate_blocks(struct inode *inode) +{ + int ret; + + inode_lock(inode); + if (is_inode_flag_set(inode, FI_OPENED_FILE)) { + inode_unlock(inode); + return 0; + } + + if (!file_should_truncate(inode)) { + set_inode_flag(inode, FI_OPENED_FILE); + inode_unlock(inode); + return 0; + } + + f2fs_down_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]); + filemap_invalidate_lock(inode->i_mapping); + + truncate_setsize(inode, i_size_read(inode)); + ret = f2fs_truncate(inode); + + filemap_invalidate_unlock(inode->i_mapping); + f2fs_up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]); + + if (!ret) + set_inode_flag(inode, FI_OPENED_FILE); + + inode_unlock(inode); + if (ret) + return ret; + + file_dont_truncate(inode); + return 0; +} + static int f2fs_file_open(struct inode *inode, struct file *filp) { int err = fscrypt_file_open(inode, filp); @@ -554,7 +590,11 @@ static int f2fs_file_open(struct inode *inode, struct file *filp)

filp->f_mode |= FMODE_NOWAIT;

- return dquot_file_open(inode, filp); + err = dquot_file_open(inode, filp); + if (err) + return err; + + return finish_preallocate_blocks(inode); }

void f2fs_truncate_data_blocks_range(struct dnode_of_data *dn, int count) diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c index ff4a4e92a..5b672df19 100644 --- a/fs/f2fs/inode.c +++ b/fs/f2fs/inode.c @@ -549,14 +549,6 @@ struct inode *f2fs_iget(struct super_block *sb, unsigned long ino) } f2fs_set_inode_flags(inode);

- if (file_should_truncate(inode) && - !is_sbi_flag_set(sbi, SBI_POR_DOING)) { - ret = f2fs_truncate(inode); - if (ret) - goto bad_inode; - file_dont_truncate(inode); - } - unlock_new_inode(inode); trace_f2fs_iget(inode); return inode;