| From bb6fbc4548b9ae7ebbd06ef72f00229df259d217 Mon Sep 17 00:00:00 2001 |
| From: Trond Myklebust <Trond.Myklebust@netapp.com> |
| Date: Thu, 11 Mar 2010 09:19:35 -0500 |
| Subject: NFS: Avoid a deadlock in nfs_release_page |
| |
| From: Trond Myklebust <Trond.Myklebust@netapp.com> |
| |
| commit bb6fbc4548b9ae7ebbd06ef72f00229df259d217 upstream. |
| |
| 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: |
| [<ffffffff8146155d>] io_schedule+0x4d/0x70 |
| [<ffffffff810d2be5>] sync_page+0x65/0xa0 |
| [<ffffffff81461b12>] __wait_on_bit_lock+0x52/0xb0 |
| [<ffffffff810d2b80>] ? sync_page+0x0/0xa0 |
| [<ffffffff810d2b64>] __lock_page+0x64/0x70 |
| [<ffffffff81070ce0>] ? wake_bit_function+0x0/0x40 |
| [<ffffffff810df1d4>] truncate_inode_pages_range+0x344/0x4a0 |
| [<ffffffff810df340>] truncate_inode_pages+0x10/0x20 |
| [<ffffffff8112cbfe>] generic_delete_inode+0x15e/0x190 |
| [<ffffffff8112cc8d>] generic_drop_inode+0x5d/0x80 |
| [<ffffffff8112bb88>] iput+0x78/0x80 |
| [<ffffffff811bc908>] nfs_dentry_iput+0x38/0x50 |
| [<ffffffff811285f4>] dentry_iput+0x84/0x110 |
| [<ffffffff811286ae>] d_kill+0x2e/0x60 |
| [<ffffffff8112912a>] dput+0x7a/0x170 |
| [<ffffffff8111e925>] path_put+0x15/0x40 |
| [<ffffffff811c3a44>] __put_nfs_open_context+0xa4/0xb0 |
| [<ffffffff811cb5d0>] ? nfs_free_request+0x0/0x50 |
| [<ffffffff811c3b0b>] put_nfs_open_context+0xb/0x10 |
| [<ffffffff811cb5f9>] nfs_free_request+0x29/0x50 |
| [<ffffffff81234b7e>] kref_put+0x8e/0xe0 |
| [<ffffffff811cb594>] nfs_release_request+0x14/0x20 |
| [<ffffffff811cf769>] nfs_find_and_lock_request+0x89/0xa0 |
| [<ffffffff811d1180>] nfs_wb_page+0x80/0x110 |
| [<ffffffff811c0770>] nfs_release_page+0x70/0x90 |
| [<ffffffff810d18ee>] try_to_release_page+0x5e/0x80 |
| [<ffffffff810e1178>] shrink_page_list+0x638/0x860 |
| [<ffffffff810e19de>] 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 <Trond.Myklebust@netapp.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> |
| |
| --- |
| fs/nfs/pagelist.c | 23 +++++++++++++---------- |
| 1 file changed, 13 insertions(+), 10 deletions(-) |
| |
| --- a/fs/nfs/pagelist.c |
| +++ b/fs/nfs/pagelist.c |
| @@ -112,12 +112,10 @@ void nfs_unlock_request(struct nfs_page |
| */ |
| 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_p |
| */ |
| 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 nf |
| * 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 |
| { |
| 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); |
| } |
| |