NeilBrown wrote:
OCFS2 can return -ERESTARTSYS from write requests (and possibly
elsewhere) if there is a signal pending.
If nfsd is shutdown (by sending a signal to each thread) while there
is still an IO load from the client, each thread could handle one last
request with a signal pending. This can result in -ERESTARTSYS
which is not understood by nfserrno() and so is reflected back to
the client as nfserr_io aka -EIO. This is wrong.
Instead, interpret ERESTARTSYS to mean "don't send a reply".
The client will resend and - if the server is restarted - the write will
(hopefully) be successful and everyone will be happy.
Why not handle -ERESTARTSYS in the same fashion as -ETIMEDOUT, ie.
leading to a EJUKEBOX sort of error being returned if possible?
Simply not returning is a bad thing to do for anything other than
NFSv2. It is especially bad for NFSv4.
ps
Signed-off-by: Neil Brown <neilb@xxxxxxx>
### Diffstat output
./fs/nfsd/nfsproc.c | 1 +
1 file changed, 1 insertion(+)
----
Funny how the shortest patches sometimes have the longest
descriptions.
The symptom that I narrowed down to this was:
copy a large file via NFS to an OCFS2 filesystem, and restart
the nfs server during the copy.
The 'cp' might get an -EIO, and the file will be corrupted -
presumably holes in the middle were writes appeared to fail.
diff .prev/fs/nfsd/nfsproc.c ./fs/nfsd/nfsproc.c
--- .prev/fs/nfsd/nfsproc.c 2008-06-13 21:31:53.000000000 +1000
+++ ./fs/nfsd/nfsproc.c 2008-06-13 21:31:57.000000000 +1000
@@ -614,6 +614,7 @@ nfserrno (int errno)
#endif
{ nfserr_stale, -ESTALE },
{ nfserr_jukebox, -ETIMEDOUT },
+ { nfserr_dropit, -ERESTARTSYS },
{ nfserr_dropit, -EAGAIN },
{ nfserr_dropit, -ENOMEM },
{ nfserr_badname, -ESRCH },
### Diffstat output
./fs/nfsd/nfsproc.c | 1 +
1 file changed, 1 insertion(+)
diff .prev/fs/nfsd/nfsproc.c ./fs/nfsd/nfsproc.c
--- .prev/fs/nfsd/nfsproc.c 2008-06-13 21:31:53.000000000 +1000
+++ ./fs/nfsd/nfsproc.c 2008-06-13 21:31:57.000000000 +1000
@@ -614,6 +614,7 @@ nfserrno (int errno)
#endif
{ nfserr_stale, -ESTALE },
{ nfserr_jukebox, -ETIMEDOUT },
+ { nfserr_dropit, -ERESTARTSYS },
{ nfserr_dropit, -EAGAIN },
{ nfserr_dropit, -ENOMEM },
{ nfserr_badname, -ESRCH },
--
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