On 8/14/23 13:02, Miklos Szeredi wrote:
On Mon, 14 Aug 2023 at 08:03, Jürg Billeter <j@xxxxxxxxx> wrote:
Since v6.3-rc1 commit 5a8bee63b1 ("fuse: in fuse_flush only wait if
someone wants the return code") `fput()` is called asynchronously if a
file is closed as part of a process exiting, i.e., if there was no
explicit `close()` before exit.
If the file was open for writing, also `put_write_access()` is called
asynchronously as part of the async `fput()`.
If that newly written file is an executable, attempting to `execve()`
the new file can fail with `ETXTBSY` if it's called after the writer
process exited but before the async `fput()` has run.
Thanks for the report.
At this point, I think it would be best to revert the original patch,
since only v6.4 has it.
The original fix was already a workaround, and I don't see a clear
path forward in this direction. We need to see if there's better
direction.
Ideas?
Is there a good reason to flush O_RDONLY?
fuse: Avoid flush for O_RDONLY
From: Bernd Schubert <bschubert@xxxxxxx>
A file opened in read-only moded does not have data to be
flushed, so no need to send flush at all.
This also mitigates -EBUSY for executables, which is due to
async flush with commit 5a8bee63b1.
Fixes: 5a8bee63b1 (unless executable opened in rw)
Signed-off-by: Bernd Schubert <bschubert@xxxxxxx>
index 89d97f6188e0..e058a6af6751 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -545,7 +545,8 @@ static int fuse_flush(struct file *file, fl_owner_t id)
if (fuse_is_bad(inode))
return -EIO;
- if (ff->open_flags & FOPEN_NOFLUSH && !fm->fc->writeback_cache)
+ if ((ff->open_flags & FOPEN_NOFLUSH && !fm->fc->writeback_cache) ||
+ ((file->f_flags & O_ACCMODE) == O_RDONLY))
return 0;
fa = kzalloc(sizeof(*fa), GFP_KERNEL);
