6.4-stable review patch. If anyone has any objections, please let me know.
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From: Chao Yu chao@kernel.org
[ Upstream commit b5ab3276eb69cacf44ecfb11b2bfab73096ff4e4 ]
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/ i_sem 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 Signed-off-by: Jaegeuk Kim jaegeuk@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- fs/f2fs/f2fs.h | 3 ++- fs/f2fs/file.c | 23 ++++++++++++++++++----- 2 files changed, 20 insertions(+), 6 deletions(-)
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h index 271d4e7b22c91..395d23ab149da 100644 --- a/fs/f2fs/f2fs.h +++ b/fs/f2fs/f2fs.h @@ -4469,7 +4469,8 @@ 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 ead75c4e833d2..f1be41014180a 100644 --- a/fs/f2fs/file.c +++ b/fs/f2fs/file.c @@ -528,7 +528,11 @@ static int f2fs_file_mmap(struct file *file, struct vm_area_struct *vma)
file_accessed(file); vma->vm_ops = &f2fs_file_vm_ops; + + f2fs_down_read(&F2FS_I(inode)->i_sem); set_inode_flag(inode, FI_MMAP_FILE); + f2fs_up_read(&F2FS_I(inode)->i_sem); + return 0; }
@@ -1920,12 +1924,19 @@ static int f2fs_setflags_common(struct inode *inode, u32 iflags, u32 mask) int err = f2fs_convert_inline_inode(inode); if (err) return err; - if (!f2fs_may_compress(inode)) - return -EINVAL; - if (S_ISREG(inode->i_mode) && F2FS_HAS_BLOCKS(inode)) + + f2fs_down_write(&F2FS_I(inode)->i_sem); + if (!f2fs_may_compress(inode) || + (S_ISREG(inode->i_mode) && + F2FS_HAS_BLOCKS(inode))) { + f2fs_up_write(&F2FS_I(inode)->i_sem); return -EINVAL; - if (set_compress_context(inode)) - return -EOPNOTSUPP; + } + err = set_compress_context(inode); + f2fs_up_write(&F2FS_I(inode)->i_sem); + + if (err) + return err; } }
@@ -3953,6 +3964,7 @@ static int f2fs_ioc_set_compress_option(struct file *filp, unsigned long arg) file_start_write(filp); inode_lock(inode);
+ f2fs_down_write(&F2FS_I(inode)->i_sem); if (f2fs_is_mmap_file(inode) || get_dirty_pages(inode)) { ret = -EBUSY; goto out; @@ -3972,6 +3984,7 @@ static int f2fs_ioc_set_compress_option(struct file *filp, unsigned long arg) f2fs_warn(sbi, "compression algorithm is successfully set, " "but current kernel doesn't support this algorithm."); out: + f2fs_up_write(&F2FS_I(inode)->i_sem); inode_unlock(inode); file_end_write(filp);