On 2010-11-04 17:22, Fred Isaman wrote:
> This prepares for future changes, where the layout state needs
> to change atomically with several other variables. In particular,
> it will need to know if lo->segs is empty. Moreover, the
> layoutstateid is not really a read-mostly structure, as it is
> written on each LAYOUTGET.
>
> Signed-off-by: Fred Isaman <iisaman@xxxxxxxxxx>
> ---
> fs/nfs/callback_proc.c | 8 +++---
> fs/nfs/nfs4xdr.c | 2 +
> fs/nfs/pnfs.c | 55 ++++++++++++++---------------------------------
> fs/nfs/pnfs.h | 4 +--
> 4 files changed, 24 insertions(+), 45 deletions(-)
>
> diff --git a/fs/nfs/callback_proc.c b/fs/nfs/callback_proc.c
> index 84c5a1b..3e022a8 100644
> --- a/fs/nfs/callback_proc.c
> +++ b/fs/nfs/callback_proc.c
> @@ -135,12 +135,11 @@ static bool
> pnfs_is_next_layout_stateid(const struct pnfs_layout_hdr *lo,
> const nfs4_stateid stateid)
> {
> - int seqlock;
> bool res;
> u32 oldseqid, newseqid;
>
> - do {
> - seqlock = read_seqbegin(&lo->seqlock);
> + spin_lock(&lo->inode->i_lock);
> + {
> oldseqid = be32_to_cpu(lo->stateid.stateid.seqid);
> newseqid = be32_to_cpu(stateid.stateid.seqid);
> res = !memcmp(lo->stateid.stateid.other,
> @@ -158,7 +157,8 @@ pnfs_is_next_layout_stateid(const struct pnfs_layout_hdr *lo,
> if (res)
> res = (newseqid == 1);
> }
> - } while (read_seqretry(&lo->seqlock, seqlock));
> + }
> + spin_unlock(&lo->inode->i_lock);
>
> return res;
> }
> diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c
> index 6d9ef2b..b71a482 100644
> --- a/fs/nfs/nfs4xdr.c
> +++ b/fs/nfs/nfs4xdr.c
> @@ -1915,7 +1915,9 @@ encode_layoutreturn(struct xdr_stream *xdr,
> p = reserve_space(xdr, 16 + NFS4_STATEID_SIZE);
> p = xdr_encode_hyper(p, args->range.offset);
> p = xdr_encode_hyper(p, args->range.length);
> + spin_lock(&args->inode->i_lock);
> pnfs_copy_layout_stateid(&stateid, NFS_I(args->inode)->layout);
> + spin_unlock(&args->inode->i_lock);
> p = xdr_encode_opaque_fixed(p, &stateid.data,
> NFS4_STATEID_SIZE);
> p = reserve_space(xdr, 4);
> diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
> index 4e5c68b..01ecb95 100644
> --- a/fs/nfs/pnfs.c
> +++ b/fs/nfs/pnfs.c
> @@ -456,7 +456,7 @@ pnfs_set_layout_stateid(struct pnfs_layout_hdr *lo,
> nfs4_stateid *old = &lo->stateid;
> bool overwrite = false;
>
> - write_seqlock(&lo->seqlock);
> + assert_spin_locked(&lo->inode->i_lock);
> if (!test_bit(NFS_LAYOUT_STATEID_SET, &lo->state) ||
> memcmp(old->stateid.other, new->stateid.other, sizeof(new->stateid.other)))
> overwrite = true;
> @@ -470,54 +470,34 @@ pnfs_set_layout_stateid(struct pnfs_layout_hdr *lo,
> }
> if (overwrite)
> memcpy(&old->stateid, &new->stateid, sizeof(new->stateid));
> - write_sequnlock(&lo->seqlock);
> -}
> -
> -static void
> -pnfs_layout_from_open_stateid(struct pnfs_layout_hdr *lo,
> - struct nfs4_state *state)
> -{
> - int seq;
> -
> - dprintk("--> %s\n", __func__);
> - write_seqlock(&lo->seqlock);
> - do {
> - seq = read_seqbegin(&state->seqlock);
> - memcpy(lo->stateid.data, state->stateid.data,
> - sizeof(state->stateid.data));
> - } while (read_seqretry(&state->seqlock, seq));
> - set_bit(NFS_LAYOUT_STATEID_SET, &lo->state);
> - write_sequnlock(&lo->seqlock);
> - dprintk("<-- %s\n", __func__);
> }
>
> /* Layoutreturn may use an invalid stateid, just copy what is there */
> void pnfs_copy_layout_stateid(nfs4_stateid *dst, struct pnfs_layout_hdr *lo)
> {
> - int seq;
> -
> - do {
> - seq = read_seqbegin(&lo->seqlock);
> - memcpy(dst->data, lo->stateid.data, sizeof(lo->stateid.data));
> - } while (read_seqretry(&lo->seqlock, seq));
> + assert_spin_locked(&lo->inode->i_lock);
> + memcpy(dst->data, lo->stateid.data, sizeof(lo->stateid.data));
This function is just redundant now.
Let's just open code its two users.
Benny
> }
>
> void
> pnfs_get_layout_stateid(nfs4_stateid *dst, struct pnfs_layout_hdr *lo,
> struct nfs4_state *open_state)
> {
> - int seq;
> -
> dprintk("--> %s\n", __func__);
> - do {
> - seq = read_seqbegin(&lo->seqlock);
> - if (!test_bit(NFS_LAYOUT_STATEID_SET, &lo->state)) {
> - /* This will trigger retry of the read */
> - pnfs_layout_from_open_stateid(lo, open_state);
> - } else
> - memcpy(dst->data, lo->stateid.data,
> - sizeof(lo->stateid.data));
> - } while (read_seqretry(&lo->seqlock, seq));
> + spin_lock(&lo->inode->i_lock);
> + if (!test_bit(NFS_LAYOUT_STATEID_SET, &lo->state)) {
> + int seq;
> +
> + do {
> + seq = read_seqbegin(&open_state->seqlock);
> + memcpy(dst->data, open_state->stateid.data,
> + sizeof(open_state->stateid.data));
> + } while (read_seqretry(&open_state->seqlock, seq));
> + set_bit(NFS_LAYOUT_STATEID_SET, &lo->state);
> + } else
> + memcpy(dst->data, lo->stateid.data,
> + sizeof(lo->stateid.data));
> + spin_unlock(&lo->inode->i_lock);
> dprintk("<-- %s\n", __func__);
> }
>
> @@ -791,7 +771,6 @@ alloc_init_layout_hdr(struct inode *ino)
> lo->refcount = 1;
> INIT_LIST_HEAD(&lo->layouts);
> INIT_LIST_HEAD(&lo->segs);
> - seqlock_init(&lo->seqlock);
> lo->inode = ino;
> return lo;
> }
> diff --git a/fs/nfs/pnfs.h b/fs/nfs/pnfs.h
> index 000acf0..de4eaa8 100644
> --- a/fs/nfs/pnfs.h
> +++ b/fs/nfs/pnfs.h
> @@ -96,7 +96,6 @@ struct pnfs_layout_hdr {
> struct list_head layouts; /* other client layouts */
> struct list_head segs; /* layout segments list */
> int roc_iomode;/* return on close iomode, 0=none */
> - seqlock_t seqlock; /* Protects the stateid */
> nfs4_stateid stateid;
> unsigned long state;
> struct rpc_cred *cred; /* layoutcommit credential */
> @@ -224,9 +223,8 @@ static inline int lo_fail_bit(u32 iomode)
>
> static inline void pnfs_invalidate_layout_stateid(struct pnfs_layout_hdr *lo)
> {
> - write_seqlock(&lo->seqlock);
> + assert_spin_locked(&lo->inode->i_lock);
> clear_bit(NFS_LAYOUT_STATEID_SET, &lo->state);
> - write_sequnlock(&lo->seqlock);
> }
>
> static inline void get_lseg(struct pnfs_layout_segment *lseg)
--
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