| Message ID | 8c2e537199608a446d5f97ea0dda319d2b9c0dad.1719937610.git.boris@bur.io (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | btrfs-progs: receive: retry encoded_write on EPERM | expand |
On Tue, Jul 02, 2024 at 09:27:49AM -0700, Boris Burkov wrote: > encoded_write fails if we run without CAP_SYS_ADMIN, but the decompress > and write fallback could succeed if we are running with write > permissions on the file. Therefore, it is helpful to fall back on EPERM > as well. While this will increase the "silent failure" rate of encoded > writes, we do have the verbose log in place to debug that while setting > up a receive workflow that expects encoded_write. > > Signed-off-by: Boris Burkov <boris@bur.io> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Thanks, Josef
在 2024/7/3 01:57, Boris Burkov 写道: > encoded_write fails if we run without CAP_SYS_ADMIN, but the decompress > and write fallback could succeed if we are running with write > permissions on the file. Therefore, it is helpful to fall back on EPERM > as well. While this will increase the "silent failure" rate of encoded > writes, we do have the verbose log in place to debug that while setting > up a receive workflow that expects encoded_write. > > Signed-off-by: Boris Burkov <boris@bur.io> Reviewed-by: Qu Wenruo <wqu@suse.com> Thanks, Qu > --- > cmds/receive.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/cmds/receive.c b/cmds/receive.c > index 412bc8afe..9101e8ccf 100644 > --- a/cmds/receive.c > +++ b/cmds/receive.c > @@ -1285,7 +1285,8 @@ static int process_encoded_write(const char *path, const void *data, u64 offset, > if (ret >= 0) > return 0; > /* Fall back for these errors, fail hard for anything else. */ > - if (errno != ENOSPC && errno != ENOTTY && errno != EINVAL) { > + if (errno != ENOSPC && errno != ENOTTY && > + errno != EINVAL && errno != EPERM) { > ret = -errno; > error("encoded_write: writing to %s failed: %m", path); > return ret;
On Tue, Jul 02, 2024 at 09:27:49AM -0700, Boris Burkov wrote: > encoded_write fails if we run without CAP_SYS_ADMIN, but the decompress > and write fallback could succeed if we are running with write > permissions on the file. Therefore, it is helpful to fall back on EPERM > as well. While this will increase the "silent failure" rate of encoded > writes, we do have the verbose log in place to debug that while setting > up a receive workflow that expects encoded_write. I'm not sure this is good to have the fallback by default. There's option --force-decompress so it needs to be user's choice to avoid encoded writes. Otherwise if I have a stream with encoded data and receive it I expect to be as close to the original as possible. Once there's encryption implemented the fallback will interfere with availability of the key. The problem with automatic fallback is that it cannot be disabled and it does not fail so user can't know that it's been silenly not encoded written. Whether a steram contains an encoded write cannot be known upfront, I think we should add more options how to handle the encoded write. Modes like 'always', 'fallback'. The code change itself is simple, this is about defining the expected use cases.
diff --git a/cmds/receive.c b/cmds/receive.c index 412bc8afe..9101e8ccf 100644 --- a/cmds/receive.c +++ b/cmds/receive.c @@ -1285,7 +1285,8 @@ static int process_encoded_write(const char *path, const void *data, u64 offset, if (ret >= 0) return 0; /* Fall back for these errors, fail hard for anything else. */ - if (errno != ENOSPC && errno != ENOTTY && errno != EINVAL) { + if (errno != ENOSPC && errno != ENOTTY && + errno != EINVAL && errno != EPERM) { ret = -errno; error("encoded_write: writing to %s failed: %m", path); return ret;
encoded_write fails if we run without CAP_SYS_ADMIN, but the decompress and write fallback could succeed if we are running with write permissions on the file. Therefore, it is helpful to fall back on EPERM as well. While this will increase the "silent failure" rate of encoded writes, we do have the verbose log in place to debug that while setting up a receive workflow that expects encoded_write. Signed-off-by: Boris Burkov <boris@bur.io> --- cmds/receive.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)