[PATCH 5/6] f2fs: fix to restrict condition of compress inode conversion

[Chao Yu]

This patch adds i_size check during compress inode conversion in order
to avoid .page_mkwrite races w/ conversion.

Fixes: 4c8ff7095bef ("f2fs: support data compression")
Signed-off-by: Chao Yu <chao@xxxxxxxxxx>
---
 fs/f2fs/f2fs.h | 8 +++++++-
 fs/f2fs/file.c | 5 ++---
 2 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 65294e3b0bef..c9b8a1953913 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -4397,13 +4397,19 @@ static inline int set_compress_context(struct inode *inode)
 #endif
 }
 
+static inline bool inode_has_data(struct inode *inode)
+{
+	return (S_ISREG(inode->i_mode) &&
+		(F2FS_HAS_BLOCKS(inode) || i_size_read(inode)));
+}
+
 static inline bool f2fs_disable_compressed_file(struct inode *inode)
 {
 	struct f2fs_inode_info *fi = F2FS_I(inode);
 
 	if (!f2fs_compressed_file(inode))
 		return true;
-	if (S_ISREG(inode->i_mode) && F2FS_HAS_BLOCKS(inode))
+	if (inode_has_data(inode))
 		return false;
 
 	fi->i_flags &= ~F2FS_COMPR_FL;
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 1a3c29a9a6a0..8af4b29c3e1a 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -1922,8 +1922,7 @@ static int f2fs_setflags_common(struct inode *inode, u32 iflags, u32 mask)
 
 			f2fs_down_write(&F2FS_I(inode)->i_sem);
 			if (!f2fs_may_compress(inode) ||
-					(S_ISREG(inode->i_mode) &&
-					F2FS_HAS_BLOCKS(inode))) {
+					inode_has_data(inode)) {
 				f2fs_up_write(&F2FS_I(inode)->i_sem);
 				return -EINVAL;
 			}
@@ -3996,7 +3995,7 @@ static int f2fs_ioc_set_compress_option(struct file *filp, unsigned long arg)
 		goto out;
 	}
 
-	if (F2FS_HAS_BLOCKS(inode)) {
+	if (inode_has_data(inode)) {
 		ret = -EFBIG;
 		goto out;
 	}
-- 
2.40.1