[f2fs-dev] [PATCH 4/4] f2fs: atomic: fix to forbid dio in atomic_file

[Chao Yu <chao@kernel.org>]

atomic write can only be used via buffered IO, let's fail direct IO on
atomic_file and return -EOPNOTSUPP.

Signed-off-by: Chao Yu <chao@kernel.org>
---
 fs/f2fs/file.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 0355cb054521..a527de1e7a2f 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -2150,6 +2150,7 @@ static int f2fs_ioc_start_atomic_write(struct file *filp, bool truncate)
 		goto out;
 
 	f2fs_down_write(&fi->i_gc_rwsem[WRITE]);
+	f2fs_down_write(&fi->i_gc_rwsem[READ]);
 
 	/*
 	 * Should wait end_io to count F2FS_WB_CP_DATA correctly by
@@ -2209,6 +2210,7 @@ static int f2fs_ioc_start_atomic_write(struct file *filp, bool truncate)
 	}
 	f2fs_i_size_write(fi->cow_inode, isize);
 
+	f2fs_up_write(&fi->i_gc_rwsem[READ]);
 	f2fs_up_write(&fi->i_gc_rwsem[WRITE]);
 
 	f2fs_update_time(sbi, REQ_TIME);
@@ -4537,6 +4539,13 @@ static ssize_t f2fs_dio_read_iter(struct kiocb *iocb, struct iov_iter *to)
 		f2fs_down_read(&fi->i_gc_rwsem[READ]);
 	}
 
+	/* dio is not compatible w/ atomic file */
+	if (f2fs_is_atomic_file(inode)) {
+		f2fs_up_read(&fi->i_gc_rwsem[READ]);
+		ret = -EOPNOTSUPP;
+		goto out;
+	}
+
 	/*
 	 * We have to use __iomap_dio_rw() and iomap_dio_complete() instead of
 	 * the higher-level function iomap_dio_rw() in order to ensure that the
@@ -4948,6 +4957,12 @@ static ssize_t f2fs_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 	/* Determine whether we will do a direct write or a buffered write. */
 	dio = f2fs_should_use_dio(inode, iocb, from);
 
+	/* dio is not compatible w/ atomic write */
+	if (dio && f2fs_is_atomic_file(inode)) {
+		ret = -EOPNOTSUPP;
+		goto out_unlock;
+	}
+
 	/* Possibly preallocate the blocks for the write. */
 	target_size = iocb->ki_pos + iov_iter_count(from);
 	preallocated = f2fs_preallocate_blocks(iocb, from, dio);
-- 
2.40.1



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