On Wed, 2010-03-10 at 14:31 -0500, Trond Myklebust wrote: > >From your trace it looks as if the problem is that the nfs_wb_page() is > triggering a dentry release, which deadlocks with in > truncate_inode_pages() because the _caller_ of nfs_release_page() holds > a page lock. > > As far as I can see, your iput() call above can deadlock in exactly the > same way. > > Note that shrink_page_list() is the only function that does this sort of > thing without holding a reference to the inode. OK. Does the following patch fix the deadlock for you? Cheers Trond ----------------------------------------------------------------------------------------------------------- NFS: Avoid a deadlock in nfs_release_page From: Trond Myklebust <Trond.Myklebust@xxxxxxxxxx> 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@xxxxxxxxxx> --- fs/nfs/pagelist.c | 9 +++++++-- 1 files changed, 7 insertions(+), 2 deletions(-) diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c index a12c45b..81fb4a5 100644 --- a/fs/nfs/pagelist.c +++ b/fs/nfs/pagelist.c @@ -148,10 +148,16 @@ void nfs_clear_page_tag_locked(struct nfs_page *req) 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 +171,8 @@ 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); } -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html