From aa8a45ee974dfe3ffe290daaf5db457afae56fde Mon Sep 17 00:00:00 2001 From: Peng Tao Date: Mon, 1 Dec 2014 08:22:23 +0800 Subject: [PATCH] nfs41: wait for LAYOUTRETURN before retrying LAYOUTGET Also take care to stop waiting if someone clears retry bit. Signed-off-by: Peng Tao --- fs/nfs/nfs4proc.c | 4 +++- fs/nfs/pnfs.c | 39 ++++++++++++++++++++++++++++++++++++++- fs/nfs/pnfs.h | 5 ++++- 3 files changed, 45 insertions(+), 3 deletions(-) diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c index 7e1a97a54f99..44c600aac907 100644 --- a/fs/nfs/nfs4proc.c +++ b/fs/nfs/nfs4proc.c @@ -7796,7 +7796,9 @@ static void nfs4_layoutreturn_release(void *calldata) spin_lock(&lo->plh_inode->i_lock); if (lrp->res.lrs_present) pnfs_set_layout_stateid(lo, &lrp->res.stateid, true); - clear_bit(NFS_LAYOUT_RETURN, &lo->plh_flags); + clear_bit_unlock(NFS_LAYOUT_RETURN, &lo->plh_flags); + smp_mb__after_atomic(); + wake_up_bit(&lo->plh_flags, NFS_LAYOUT_RETURN); clear_bit(NFS_LAYOUT_RETURN_BEFORE_CLOSE, &lo->plh_flags); rpc_wake_up(&NFS_SERVER(lo->plh_inode)->roc_rpcwaitq); lo->plh_block_lgets--; diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c index 893f6b5afe6a..c4c9fe606ae6 100644 --- a/fs/nfs/pnfs.c +++ b/fs/nfs/pnfs.c @@ -1398,6 +1398,26 @@ static bool pnfs_within_mdsthreshold(struct nfs_open_context *ctx, return ret; } +/* stop waiting if someone clears NFS_LAYOUT_RETRY_LAYOUTGET bit. */ +static int pnfs_layoutget_retry_bit_wait(struct wait_bit_key *key) +{ + if (!test_bit(NFS_LAYOUT_RETRY_LAYOUTGET, key->flags)) + return 1; + return nfs_wait_bit_killable(key); +} + +static bool pnfs_prepare_to_retry_layoutget(struct pnfs_layout_hdr *lo) +{ + /* + * send layoutcommit as it can hold up layoutreturn due to lseg + * reference + */ + pnfs_layoutcommit_inode(lo->plh_inode, false); + return !wait_on_bit_action(&lo->plh_flags, NFS_LAYOUT_RETURN, + pnfs_layoutget_retry_bit_wait, + TASK_UNINTERRUPTIBLE); +} + /* * Layout segment is retreived from the server if not cached. * The appropriate layout segment is referenced and returned to the caller. @@ -1444,7 +1464,8 @@ lookup_again: } /* if LAYOUTGET already failed once we don't try again */ - if (pnfs_layout_io_test_failed(lo, iomode)) + if (pnfs_layout_io_test_failed(lo, iomode) && + !pnfs_should_retry_layoutget(lo)) goto out_unlock; first = list_empty(&lo->plh_segs); @@ -1469,6 +1490,22 @@ lookup_again: goto out_unlock; } + /* + * Because we free lsegs before sending LAYOUTRETURN, we need to wait + * for LAYOUTRETURN even if first is true. + */ + if (!lseg && pnfs_should_retry_layoutget(lo) && + test_bit(NFS_LAYOUT_RETURN, &lo->plh_flags)) { + spin_unlock(&ino->i_lock); + dprintk("%s wait for layoutreturn\n", __func__); + if (pnfs_prepare_to_retry_layoutget(lo)) { + pnfs_put_layout_hdr(lo); + dprintk("%s retrying\n", __func__); + goto lookup_again; + } + goto out_put_layout_hdr; + } + if (pnfs_layoutgets_blocked(lo, &arg, 0)) goto out_unlock; atomic_inc(&lo->plh_outstanding); diff --git a/fs/nfs/pnfs.h b/fs/nfs/pnfs.h index fed6ae067acb..49a466708400 100644 --- a/fs/nfs/pnfs.h +++ b/fs/nfs/pnfs.h @@ -359,8 +359,11 @@ static inline void pnfs_set_retry_layoutget(struct pnfs_layout_hdr *lo) static inline void pnfs_clear_retry_layoutget(struct pnfs_layout_hdr *lo) { - if (test_and_clear_bit(NFS_LAYOUT_RETRY_LAYOUTGET, &lo->plh_flags)) + if (test_and_clear_bit(NFS_LAYOUT_RETRY_LAYOUTGET, &lo->plh_flags)) { atomic_dec(&lo->plh_refcount); + /* wake up waiters for LAYOUTRETURN as that is not needed */ + wake_up_bit(&lo->plh_flags, NFS_LAYOUT_RETURN); + } } static inline bool pnfs_should_retry_layoutget(struct pnfs_layout_hdr *lo) -- 2.20.1