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Commit bb6fbc4548b9ae7ebbd06ef72f00229df259d217

Authored by Trond Myklebust
1 parent b4d2314bb8
Exists in master and in 7 other branches imx_3.0.35_4.1.0, imx_3.10.17_1.0.1_ga, imx_3.10.53_1.1.0_ga, imx_3.14.28_1.0.0_ga, smarc-imx_3.10.53_1.1.0_ga, smarc-imx_3.14.28_1.0.0_ga, smarc-l5.0.0_1.0.0-ga

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:
 [<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>
Cc: stable@kernel.org

Showing 1 changed file with 13 additions and 10 deletions Side-by-side Diff

... ... @@ -112,12 +112,10 @@
112 112 */
113 113 int nfs_set_page_tag_locked(struct nfs_page *req)
114 114 {
115   - struct nfs_inode *nfsi = NFS_I(req->wb_context->path.dentry->d_inode);
116   -
117 115 if (!nfs_lock_request_dontget(req))
118 116 return 0;
119 117 if (req->wb_page != NULL)
120   - radix_tree_tag_set(&nfsi->nfs_page_tree, req->wb_index, NFS_PAGE_TAG_LOCKED);
  118 + radix_tree_tag_set(&NFS_I(req->wb_context->path.dentry->d_inode)->nfs_page_tree, req->wb_index, NFS_PAGE_TAG_LOCKED);
121 119 return 1;
122 120 }
123 121  
124 122  
... ... @@ -126,10 +124,10 @@
126 124 */
127 125 void nfs_clear_page_tag_locked(struct nfs_page *req)
128 126 {
129   - struct inode *inode = req->wb_context->path.dentry->d_inode;
130   - struct nfs_inode *nfsi = NFS_I(inode);
131   -
132 127 if (req->wb_page != NULL) {
  128 + struct inode *inode = req->wb_context->path.dentry->d_inode;
  129 + struct nfs_inode *nfsi = NFS_I(inode);
  130 +
133 131 spin_lock(&inode->i_lock);
134 132 radix_tree_tag_clear(&nfsi->nfs_page_tree, req->wb_index, NFS_PAGE_TAG_LOCKED);
135 133 nfs_unlock_request(req);
136 134  
137 135  
... ... @@ -142,16 +140,22 @@
142 140 * nfs_clear_request - Free up all resources allocated to the request
143 141 * @req:
144 142 *
145   - * Release page resources associated with a write request after it
146   - * has completed.
  143 + * Release page and open context resources associated with a read/write
  144 + * request after it has completed.
147 145 */
148 146 void nfs_clear_request(struct nfs_page *req)
149 147 {
150 148 struct page *page = req->wb_page;
  149 + struct nfs_open_context *ctx = req->wb_context;
  150 +
151 151 if (page != NULL) {
152 152 page_cache_release(page);
153 153 req->wb_page = NULL;
154 154 }
  155 + if (ctx != NULL) {
  156 + put_nfs_open_context(ctx);
  157 + req->wb_context = NULL;
  158 + }
155 159 }
156 160  
157 161  
158 162  
... ... @@ -165,9 +169,8 @@
165 169 {
166 170 struct nfs_page *req = container_of(kref, struct nfs_page, wb_kref);
167 171  
168   - /* Release struct file or cached credential */
  172 + /* Release struct file and open context */
169 173 nfs_clear_request(req);
170   - put_nfs_open_context(req->wb_context);
171 174 nfs_page_free(req);
172 175 }
173 176