Hello, Okajima-san, and folks,
A recent Docker issue reports that AUFS does not work with `fcntl(fd,
F_SETFL, O_APPEND)`.
How to reproduce the situation is also attached in the issue ticket.
https://github.com/docker/docker/issues/20199
I found a workaround which disables `aufs_write()` and uses
`aufs_write_iter()` instead, even for non-vectorized `write()` calls.
I tested with Ubuntu kernel 4.2.0-27.32 (AUFS 20150629).
diff --git a/fs/aufs/f_op.c b/fs/aufs/f_op.c
index 2c34864..efc46bc 100644
--- a/fs/aufs/f_op.c
+++ b/fs/aufs/f_op.c
@@ -708,8 +708,8 @@ const struct file_operations aufs_file_fop = {
.llseek = default_llseek,
- .read = aufs_read,
- .write = aufs_write,
+ // .read = aufs_read,
+ // .write = aufs_write,
.read_iter = aufs_read_iter,
.write_iter = aufs_write_iter,
In this workaround, underlying `h_file->f_op->write_iter` calls
`generic_write_checks()`, and `generic_write_checks()` handles
`fcntl(fd, F_SETFL, O_APPEND)`.
Although it should be possible to add `O_APPEND` check for
`aufs_write`, removing `aufs_write` seems the simplest solution.
I know that the `write_iter` operation does not exist in Linux < 3.16,
but I believe it does not matter because AUFS is no longer maintained
for Linux < 3.18.
Do you think it is possible to adopt my workaround?
Regards,
Akihiro Suda
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