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Mon, 20 Dec 2010 18:20:59 -0800 (PST) From: Fred Isaman To: linux-nfs@vger.kernel.org Cc: Trond Myklebust Subject: [PATCH 10/14] pnfs: wave 2: change lo refcounting to atomic_t Date: Mon, 20 Dec 2010 21:20:42 -0500 Message-Id: <1292898046-7336-11-git-send-email-iisaman@netapp.com> X-Mailer: git-send-email 1.7.2.1 In-Reply-To: <1292898046-7336-1-git-send-email-iisaman@netapp.com> References: <1292898046-7336-1-git-send-email-iisaman@netapp.com> Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org X-Greylist: IP, sender and recipient auto-whitelisted, not delayed by milter-greylist-4.2.3 (demeter1.kernel.org [140.211.167.41]); Tue, 21 Dec 2010 02:21:08 +0000 (UTC) diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c index 8dbe90c..f49d288 100644 --- a/fs/nfs/pnfs.c +++ b/fs/nfs/pnfs.c @@ -177,34 +177,40 @@ EXPORT_SYMBOL_GPL(pnfs_unregister_layoutdriver); * pNFS client layout cache */ +/* Need to hold i_lock if caller does not already hold reference */ static void -get_layout_hdr_locked(struct pnfs_layout_hdr *lo) +get_layout_hdr(struct pnfs_layout_hdr *lo) { - assert_spin_locked(&lo->inode->i_lock); - lo->refcount++; + atomic_inc(&lo->plh_refcount); } static void -put_layout_hdr_locked(struct pnfs_layout_hdr *lo) +destroy_layout_hdr(struct pnfs_layout_hdr *lo) { - assert_spin_locked(&lo->inode->i_lock); - BUG_ON(lo->refcount == 0); + dprintk("%s: freeing layout cache %p\n", __func__, lo); + BUG_ON(!list_empty(&lo->layouts)); + NFS_I(lo->inode)->layout = NULL; + kfree(lo); +} - lo->refcount--; - if (!lo->refcount) { - dprintk("%s: freeing layout cache %p\n", __func__, lo); - BUG_ON(!list_empty(&lo->layouts)); - NFS_I(lo->inode)->layout = NULL; - kfree(lo); - } +static void +put_layout_hdr_locked(struct pnfs_layout_hdr *lo) +{ + BUG_ON(atomic_read(&lo->plh_refcount) == 0); + if (atomic_dec_and_test(&lo->plh_refcount)) + destroy_layout_hdr(lo); } void -put_layout_hdr(struct inode *inode) +put_layout_hdr(struct pnfs_layout_hdr *lo) { - spin_lock(&inode->i_lock); - put_layout_hdr_locked(NFS_I(inode)->layout); - spin_unlock(&inode->i_lock); + struct inode *inode = lo->inode; + + BUG_ON(atomic_read(&lo->plh_refcount) == 0); + if (atomic_dec_and_lock(&lo->plh_refcount, &inode->i_lock)) { + destroy_layout_hdr(lo); + spin_unlock(&inode->i_lock); + } } static void @@ -224,7 +230,7 @@ static void free_lseg(struct pnfs_layout_segment *lseg) BUG_ON(atomic_read(&lseg->pls_refcount) != 0); NFS_SERVER(ino)->pnfs_curr_ld->free_lseg(lseg); /* Matched by get_layout_hdr in pnfs_insert_layout */ - put_layout_hdr(ino); + put_layout_hdr(NFS_I(ino)->layout); } /* The use of tmp_list is necessary because pnfs_curr_ld->free_lseg @@ -484,7 +490,7 @@ pnfs_insert_layout(struct pnfs_layout_hdr *lo, __func__, lseg, lseg->range.iomode, lseg->range.offset, lseg->range.length); } - get_layout_hdr_locked(lo); + get_layout_hdr(lo); dprintk("%s:Return\n", __func__); } @@ -497,7 +503,7 @@ alloc_init_layout_hdr(struct inode *ino) lo = kzalloc(sizeof(struct pnfs_layout_hdr), GFP_KERNEL); if (!lo) return NULL; - lo->refcount = 1; + atomic_set(&lo->plh_refcount, 1); INIT_LIST_HEAD(&lo->layouts); INIT_LIST_HEAD(&lo->segs); lo->inode = ino; @@ -612,7 +618,7 @@ pnfs_update_layout(struct inode *ino, goto out_unlock; atomic_inc(&lo->plh_outstanding); - get_layout_hdr_locked(lo); + get_layout_hdr(lo); if (list_empty(&lo->segs)) { /* The lo must be on the clp list if there is any * chance of a CB_LAYOUTRECALL(FILE) coming in. @@ -635,7 +641,7 @@ pnfs_update_layout(struct inode *ino, spin_unlock(&ino->i_lock); } atomic_dec(&lo->plh_outstanding); - put_layout_hdr(ino); + put_layout_hdr(lo); out: dprintk("%s end, state 0x%lx lseg %p\n", __func__, nfsi->layout->plh_flags, lseg); diff --git a/fs/nfs/pnfs.h b/fs/nfs/pnfs.h index 0b8070f..3cf6856 100644 --- a/fs/nfs/pnfs.h +++ b/fs/nfs/pnfs.h @@ -65,7 +65,7 @@ struct pnfs_layoutdriver_type { }; struct pnfs_layout_hdr { - unsigned long refcount; + atomic_t plh_refcount; struct list_head layouts; /* other client layouts */ struct list_head segs; /* layout segments list */ nfs4_stateid stateid; @@ -147,7 +147,7 @@ void unset_pnfs_layoutdriver(struct nfs_server *); int pnfs_layout_process(struct nfs4_layoutget *lgp); void pnfs_destroy_layout(struct nfs_inode *); void pnfs_destroy_all_layouts(struct nfs_client *); -void put_layout_hdr(struct inode *inode); +void put_layout_hdr(struct pnfs_layout_hdr *lo); int pnfs_choose_layoutget_stateid(nfs4_stateid *dst, struct pnfs_layout_hdr *lo, struct nfs4_state *open_state);