On Tue, Jun 15, 2010 at 1:33 PM, Trond Myklebust
<trond.myklebust@xxxxxxxxxx> wrote:
> On Tue, 2010-06-15 at 13:32 -0400, Fred Isaman wrote:
>> On Tue, Jun 15, 2010 at 1:06 PM, Benny Halevy <bhalevy@xxxxxxxxxxx> wrote:
>> > On Jun. 14, 2010, 21:46 -0400, Fred Isaman <iisaman@xxxxxxxxxx> wrote:
>> >> This prepares for the next patch.
>> >>
>> >> NOTE this doesn't really fix any current race, since
>> >> layout going to NULL is OK. But layout changing from NULL to nonNULL
>> >> is a real race that is not fixed
>> >>
>> >> Signed-off-by: Fred Isaman <iisaman@xxxxxxxxxx>
>> >> ---
>> >> fs/nfs/nfs4state.c | 5 +++--
>> >> fs/nfs/pnfs.c | 11 +++++++++++
>> >> include/linux/nfs4_pnfs.h | 2 ++
>> >> 3 files changed, 16 insertions(+), 2 deletions(-)
>> >>
>> >> diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c
>> >> index d5144bd..8a7a64c 100644
>> >> --- a/fs/nfs/nfs4state.c
>> >> +++ b/fs/nfs/nfs4state.c
>> >> @@ -594,11 +594,12 @@ static void __nfs4_close(struct path *path, struct nfs4_state *state,
>> >> } else {
>> >> #ifdef CONFIG_NFS_V4_1
>> >> struct nfs_inode *nfsi = NFS_I(state->inode);
>> >> + int roc = nfs4_roc_iomode(nfsi);
>> >>
>> >> - if (has_layout(nfsi) && nfsi->layout.roc_iomode) {
>> >> + if (roc) {
>> >> struct nfs4_pnfs_layout_segment range;
>> >>
>> >> - range.iomode = nfsi->layout.roc_iomode;
>> >> + range.iomode = roc;
>> >> range.offset = 0;
>> >> range.length = NFS4_MAX_UINT64;
>> >> pnfs_return_layout(state->inode, &range, NULL,
>> >> diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
>> >> index 6def09c..bd11ec7 100644
>> >> --- a/fs/nfs/pnfs.c
>> >> +++ b/fs/nfs/pnfs.c
>> >> @@ -321,6 +321,17 @@ pnfs_unregister_layoutdriver(struct pnfs_layoutdriver_type *ld_type)
>> >> #define BUG_ON_UNLOCKED_LO(lo) do {} while (0)
>> >> #endif /* CONFIG_SMP */
>> >>
>> >> +int nfs4_roc_iomode(struct nfs_inode *nfsi)
>> >> +{
>> >> + int rv = 0;
>> >> +
>> >> + spin_lock(&pnfs_spinlock);
>> >
>> > Why take the global lock rather than nfsi->lo_lock?
>> >
>> > Benny
>>
>> You are right. That would be a copy-paste error.
>
> What's an nfsi->lo_lock, and why do we need one?
>
> Trond
>
>
It protects nfsi->layout and its contents.
Fred
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