Messages in this thread Patch in this message | | | From | Chao Yu <> | Subject | [PATCH v2] f2fs: fix to avoid mmap vs set_compress_option case | Date | Mon, 29 May 2023 18:47:09 +0800 |
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Compression option in inode should not be changed after they have been used, however, it may happen in below race case:
Thread A Thread B - f2fs_ioc_set_compress_option - check f2fs_is_mmap_file() - check get_dirty_pages() - check F2FS_HAS_BLOCKS() - f2fs_file_mmap - set_inode_flag(FI_MMAP_FILE) - fault - do_page_mkwrite - f2fs_vm_page_mkwrite - f2fs_get_block_locked - fault_dirty_shared_page - set_page_dirty - update i_compress_algorithm - update i_log_cluster_size - update i_cluster_size
Avoid such race condition by covering f2fs_file_mmap() w/ inode lock, meanwhile add mmap file check condition in f2fs_may_compress() as well.
Fixes: e1e8debec656 ("f2fs: add F2FS_IOC_SET_COMPRESS_OPTION ioctl") Signed-off-by: Chao Yu <chao@kernel.org> --- v2: - add mmap file check condition in f2fs_may_compress() fs/f2fs/f2fs.h | 3 ++- fs/f2fs/file.c | 14 +++++++++++--- 2 files changed, 13 insertions(+), 4 deletions(-)
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h index 9bd83fb28439..0db8b37c7a4d 100644 --- a/fs/f2fs/f2fs.h +++ b/fs/f2fs/f2fs.h @@ -4487,7 +4487,8 @@ static inline bool f2fs_low_mem_mode(struct f2fs_sb_info *sbi) static inline bool f2fs_may_compress(struct inode *inode) { if (IS_SWAPFILE(inode) || f2fs_is_pinned_file(inode) || - f2fs_is_atomic_file(inode) || f2fs_has_inline_data(inode)) + f2fs_is_atomic_file(inode) || f2fs_has_inline_data(inode) || + f2fs_is_mmap_file(inode)) return false; return S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode); } diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c index 7b097ab2f5e4..685ded62fc28 100644 --- a/fs/f2fs/file.c +++ b/fs/f2fs/file.c @@ -519,17 +519,25 @@ static loff_t f2fs_llseek(struct file *file, loff_t offset, int whence) static int f2fs_file_mmap(struct file *file, struct vm_area_struct *vma) { struct inode *inode = file_inode(file); + int ret = 0; if (unlikely(f2fs_cp_error(F2FS_I_SB(inode)))) return -EIO; - if (!f2fs_is_compress_backend_ready(inode)) - return -EOPNOTSUPP; + inode_lock(inode); + + if (!f2fs_is_compress_backend_ready(inode)) { + ret = -EOPNOTSUPP; + goto out_unlock; + } file_accessed(file); vma->vm_ops = &f2fs_file_vm_ops; set_inode_flag(inode, FI_MMAP_FILE); - return 0; + +out_unlock: + inode_unlock(inode); + return ret; } static int f2fs_file_open(struct inode *inode, struct file *filp) -- 2.40.1
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