From bb6fbc4548b9ae7ebbd06ef72f00229df259d217 Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Thu, 11 Mar 2010 09:19:35 -0500 Subject: [PATCH] NFS: Avoid a deadlock in nfs_release_page J.R. Okajima reports the following deadlock: INFO: task kswapd0:305 blocked for more than 120 seconds. "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kswapd0 D 0000000000000001 0 305 2 0x00000000 ffff88001f21d4f0 0000000000000046 ffff88001fdea680 ffff88001f21c000 ffff88001f21dfd8 ffff88001f21c000 ffff88001f21dfd8 ffff88001f21dfd8 ffff88001fdea040 0000000000014c00 0000000000000001 ffff88001fdea040 Call Trace: [] io_schedule+0x4d/0x70 [] sync_page+0x65/0xa0 [] __wait_on_bit_lock+0x52/0xb0 [] ? sync_page+0x0/0xa0 [] __lock_page+0x64/0x70 [] ? wake_bit_function+0x0/0x40 [] truncate_inode_pages_range+0x344/0x4a0 [] truncate_inode_pages+0x10/0x20 [] generic_delete_inode+0x15e/0x190 [] generic_drop_inode+0x5d/0x80 [] iput+0x78/0x80 [] nfs_dentry_iput+0x38/0x50 [] dentry_iput+0x84/0x110 [] d_kill+0x2e/0x60 [] dput+0x7a/0x170 [] path_put+0x15/0x40 [] __put_nfs_open_context+0xa4/0xb0 [] ? nfs_free_request+0x0/0x50 [] put_nfs_open_context+0xb/0x10 [] nfs_free_request+0x29/0x50 [] kref_put+0x8e/0xe0 [] nfs_release_request+0x14/0x20 [] nfs_find_and_lock_request+0x89/0xa0 [] nfs_wb_page+0x80/0x110 [] nfs_release_page+0x70/0x90 [] try_to_release_page+0x5e/0x80 [] shrink_page_list+0x638/0x860 [] shrink_zone+0x63e/0xc40 We can fix this by making the call to put_nfs_open_context() happen when we actually remove the write request from the inode (which is done by the nfsiod thread in this case). Signed-off-by: Trond Myklebust Cc: stable@kernel.org --- fs/nfs/pagelist.c | 23 +++++++++++++---------- 1 file changed, 13 insertions(+), 10 deletions(-) diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c index a12c45b65dd4..29d9d36cd5f4 100644 --- a/fs/nfs/pagelist.c +++ b/fs/nfs/pagelist.c @@ -112,12 +112,10 @@ void nfs_unlock_request(struct nfs_page *req) */ int nfs_set_page_tag_locked(struct nfs_page *req) { - struct nfs_inode *nfsi = NFS_I(req->wb_context->path.dentry->d_inode); - if (!nfs_lock_request_dontget(req)) return 0; if (req->wb_page != NULL) - radix_tree_tag_set(&nfsi->nfs_page_tree, req->wb_index, NFS_PAGE_TAG_LOCKED); + radix_tree_tag_set(&NFS_I(req->wb_context->path.dentry->d_inode)->nfs_page_tree, req->wb_index, NFS_PAGE_TAG_LOCKED); return 1; } @@ -126,10 +124,10 @@ int nfs_set_page_tag_locked(struct nfs_page *req) */ void nfs_clear_page_tag_locked(struct nfs_page *req) { - struct inode *inode = req->wb_context->path.dentry->d_inode; - struct nfs_inode *nfsi = NFS_I(inode); - if (req->wb_page != NULL) { + struct inode *inode = req->wb_context->path.dentry->d_inode; + struct nfs_inode *nfsi = NFS_I(inode); + spin_lock(&inode->i_lock); radix_tree_tag_clear(&nfsi->nfs_page_tree, req->wb_index, NFS_PAGE_TAG_LOCKED); nfs_unlock_request(req); @@ -142,16 +140,22 @@ void nfs_clear_page_tag_locked(struct nfs_page *req) * nfs_clear_request - Free up all resources allocated to the request * @req: * - * Release page resources associated with a write request after it - * has completed. + * Release page and open context resources associated with a read/write + * request after it has completed. */ void nfs_clear_request(struct nfs_page *req) { struct page *page = req->wb_page; + struct nfs_open_context *ctx = req->wb_context; + if (page != NULL) { page_cache_release(page); req->wb_page = NULL; } + if (ctx != NULL) { + put_nfs_open_context(ctx); + req->wb_context = NULL; + } } @@ -165,9 +169,8 @@ static void nfs_free_request(struct kref *kref) { struct nfs_page *req = container_of(kref, struct nfs_page, wb_kref); - /* Release struct file or cached credential */ + /* Release struct file and open context */ nfs_clear_request(req); - put_nfs_open_context(req->wb_context); nfs_page_free(req); } -- 2.39.5