From 8dd3775889345850ecddd689b5c200cdd91bd8c9 Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Thu, 15 Mar 2012 17:16:40 -0400 Subject: NFSv4.1: Clean ups and bugfixes for the pNFS read/writeback/commit code Move more pnfs-isms out of the generic commit code. Bugfixes: - filelayout_scan_commit_lists doesn't need to get/put the lseg. In fact since it is run under the inode->i_lock, the lseg_put() can deadlock. - Ensure that we distinguish between what needs to be done for commit-to-data server and what needs to be done for commit-to-MDS using the new flag PG_COMMIT_TO_DS. Otherwise we may end up calling put_lseg() on a bucket for a struct nfs_page that got written through the MDS. - Fix a case where we were using list_del() on an nfs_page->wb_list instead of list_del_init(). - filelayout_initiate_commit needs to call filelayout_commit_release on error instead of the mds_ops->rpc_release(). Otherwise it won't clear the commit lock. Cleanups: - Let the files layout manage the commit lists for the pNFS case. Don't expose stuff like pnfs_choose_commit_list, and the fact that the commit buckets hold references to the layout segment in common code. - Cast out the put_lseg() calls for the struct nfs_read/write_data->lseg into the pNFS layer from whence they came. - Let the pNFS layer manage the NFS_INO_PNFS_COMMIT bit. Signed-off-by: Trond Myklebust Cc: Fred Isaman --- fs/nfs/write.c | 124 +++++++++++++++++++++++++++++++++++---------------------- 1 file changed, 77 insertions(+), 47 deletions(-) (limited to 'fs/nfs/write.c') diff --git a/fs/nfs/write.c b/fs/nfs/write.c index a630ad65d64c..0de19f413f92 100644 --- a/fs/nfs/write.c +++ b/fs/nfs/write.c @@ -100,7 +100,6 @@ void nfs_writedata_free(struct nfs_write_data *p) void nfs_writedata_release(struct nfs_write_data *wdata) { - put_lseg(wdata->lseg); put_nfs_open_context(wdata->args.context); nfs_writedata_free(wdata); } @@ -393,8 +392,6 @@ static void nfs_inode_add_request(struct inode *inode, struct nfs_page *req) spin_unlock(&inode->i_lock); } -static struct pnfs_layout_segment *nfs_clear_request_commit(struct nfs_page *req); - /* * Remove a write request from an inode */ @@ -402,18 +399,15 @@ static void nfs_inode_remove_request(struct nfs_page *req) { struct inode *inode = req->wb_context->dentry->d_inode; struct nfs_inode *nfsi = NFS_I(inode); - struct pnfs_layout_segment *lseg; BUG_ON (!NFS_WBACK_BUSY(req)); spin_lock(&inode->i_lock); - lseg = nfs_clear_request_commit(req); set_page_private(req->wb_page, 0); ClearPagePrivate(req->wb_page); clear_bit(PG_MAPPED, &req->wb_flags); nfsi->npages--; spin_unlock(&inode->i_lock); - put_lseg(lseg); nfs_release_request(req); } @@ -424,26 +418,69 @@ nfs_mark_request_dirty(struct nfs_page *req) } #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4) -/* - * Add a request to the inode's commit list. +/** + * nfs_request_add_commit_list - add request to a commit list + * @req: pointer to a struct nfs_page + * @head: commit list head + * + * This sets the PG_CLEAN bit, updates the inode global count of + * number of outstanding requests requiring a commit as well as + * the MM page stats. + * + * The caller must _not_ hold the inode->i_lock, but must be + * holding the nfs_page lock. */ -static void -nfs_mark_request_commit(struct nfs_page *req, struct pnfs_layout_segment *lseg) +void +nfs_request_add_commit_list(struct nfs_page *req, struct list_head *head) { struct inode *inode = req->wb_context->dentry->d_inode; - struct nfs_inode *nfsi = NFS_I(inode); - struct list_head *clist; - clist = pnfs_choose_commit_list(req, lseg); - spin_lock(&inode->i_lock); set_bit(PG_CLEAN, &(req)->wb_flags); - nfs_list_add_request(req, clist); - nfsi->ncommit++; + spin_lock(&inode->i_lock); + nfs_list_add_request(req, head); + NFS_I(inode)->ncommit++; spin_unlock(&inode->i_lock); inc_zone_page_state(req->wb_page, NR_UNSTABLE_NFS); inc_bdi_stat(req->wb_page->mapping->backing_dev_info, BDI_RECLAIMABLE); __mark_inode_dirty(inode, I_DIRTY_DATASYNC); } +EXPORT_SYMBOL_GPL(nfs_request_add_commit_list); + +/** + * nfs_request_remove_commit_list - Remove request from a commit list + * @req: pointer to a nfs_page + * + * This clears the PG_CLEAN bit, and updates the inode global count of + * number of outstanding requests requiring a commit + * It does not update the MM page stats. + * + * The caller _must_ hold the inode->i_lock and the nfs_page lock. + */ +void +nfs_request_remove_commit_list(struct nfs_page *req) +{ + struct inode *inode = req->wb_context->dentry->d_inode; + + if (!test_and_clear_bit(PG_CLEAN, &(req)->wb_flags)) + return; + nfs_list_remove_request(req); + NFS_I(inode)->ncommit--; +} +EXPORT_SYMBOL_GPL(nfs_request_remove_commit_list); + + +/* + * Add a request to the inode's commit list. + */ +static void +nfs_mark_request_commit(struct nfs_page *req, struct pnfs_layout_segment *lseg) +{ + struct inode *inode = req->wb_context->dentry->d_inode; + + if (pnfs_mark_request_commit(req, lseg)) + return; + nfs_request_add_commit_list(req, &NFS_I(inode)->commit_list); +} static void nfs_clear_page_commit(struct page *page) @@ -452,18 +489,19 @@ nfs_clear_page_commit(struct page *page) dec_bdi_stat(page->mapping->backing_dev_info, BDI_RECLAIMABLE); } -static struct pnfs_layout_segment * +static void nfs_clear_request_commit(struct nfs_page *req) { - struct pnfs_layout_segment *lseg = NULL; + if (test_bit(PG_CLEAN, &req->wb_flags)) { + struct inode *inode = req->wb_context->dentry->d_inode; - if (test_and_clear_bit(PG_CLEAN, &(req)->wb_flags)) { + if (!pnfs_clear_request_commit(req)) { + spin_lock(&inode->i_lock); + nfs_request_remove_commit_list(req); + spin_unlock(&inode->i_lock); + } nfs_clear_page_commit(req->wb_page); - lseg = pnfs_clear_request_commit(req); - NFS_I(req->wb_context->dentry->d_inode)->ncommit--; - list_del(&req->wb_list); } - return lseg; } static inline @@ -490,15 +528,14 @@ int nfs_reschedule_unstable_write(struct nfs_page *req, return 0; } #else -static inline void +static void nfs_mark_request_commit(struct nfs_page *req, struct pnfs_layout_segment *lseg) { } -static inline struct pnfs_layout_segment * +static void nfs_clear_request_commit(struct nfs_page *req) { - return NULL; } static inline @@ -523,25 +560,23 @@ nfs_need_commit(struct nfs_inode *nfsi) } /* i_lock held by caller */ -int +static int nfs_scan_commit_list(struct list_head *src, struct list_head *dst, int max) { struct nfs_page *req, *tmp; int ret = 0; list_for_each_entry_safe(req, tmp, src, wb_list) { - if (nfs_lock_request_dontget(req)) { - kref_get(&req->wb_kref); - list_move_tail(&req->wb_list, dst); - clear_bit(PG_CLEAN, &(req)->wb_flags); - ret++; - if (ret == max) - break; - } + if (!nfs_lock_request(req)) + continue; + nfs_request_remove_commit_list(req); + nfs_list_add_request(req, dst); + ret++; + if (ret == max) + break; } return ret; } -EXPORT_SYMBOL_GPL(nfs_scan_commit_list); /* * nfs_scan_commit - Scan an inode for commit requests @@ -559,14 +594,12 @@ nfs_scan_commit(struct inode *inode, struct list_head *dst) spin_lock(&inode->i_lock); if (nfsi->ncommit > 0) { + const int max = INT_MAX; int pnfs_ret; - ret = nfs_scan_commit_list(&nfsi->commit_list, dst, INT_MAX); - pnfs_ret = pnfs_scan_commit_lists(inode, INT_MAX - ret); - if (pnfs_ret) { - ret += pnfs_ret; - set_bit(NFS_INO_PNFS_COMMIT, &nfsi->flags); - } + ret = nfs_scan_commit_list(&nfsi->commit_list, dst, max); + pnfs_ret = pnfs_scan_commit_lists(inode, max - ret); + ret += pnfs_ret; nfsi->ncommit -= ret; } spin_unlock(&inode->i_lock); @@ -601,7 +634,6 @@ static struct nfs_page *nfs_try_to_update_request(struct inode *inode, unsigned int rqend; unsigned int end; int error; - struct pnfs_layout_segment *lseg = NULL; if (!PagePrivate(page)) return NULL; @@ -637,8 +669,6 @@ static struct nfs_page *nfs_try_to_update_request(struct inode *inode, spin_lock(&inode->i_lock); } - lseg = nfs_clear_request_commit(req); - /* Okay, the request matches. Update the region */ if (offset < req->wb_offset) { req->wb_offset = offset; @@ -650,7 +680,7 @@ static struct nfs_page *nfs_try_to_update_request(struct inode *inode, req->wb_bytes = rqend - req->wb_offset; out_unlock: spin_unlock(&inode->i_lock); - put_lseg(lseg); + nfs_clear_request_commit(req); return req; out_flushme: spin_unlock(&inode->i_lock); @@ -1337,7 +1367,6 @@ void nfs_commitdata_release(void *data) { struct nfs_write_data *wdata = data; - put_lseg(wdata->lseg); put_nfs_open_context(wdata->args.context); nfs_commit_free(wdata); } @@ -1647,6 +1676,7 @@ int nfs_wb_page_cancel(struct inode *inode, struct page *page) if (req == NULL) break; if (nfs_lock_request_dontget(req)) { + nfs_clear_request_commit(req); nfs_inode_remove_request(req); /* * In case nfs_inode_remove_request has marked the -- cgit v1.2.3