From 5ce86eaccfa8859c369514d85387585241c81ca5 Mon Sep 17 00:00:00 2001 From: wang di Date: Thu, 10 Nov 2016 12:30:43 -0500 Subject: [PATCH] staging: lustre: llite: lookup master inode by ilookup5_nowait Do not lookup master inode by ilookup5, instead it should use ilookup5_nowait, otherwise it will cause dead lock, 1. Client1 send chmod req to the MDT0, then on MDT0, it enqueues master and all of its slaves lock, (mdt_attr_set() ->mdt_lock_slaves()), after gets master and stripe0 lock, it will send the enqueue request(for stripe1) to MDT1, then MDT1 finds the lock has been granted to client2. Then MDT1 sends blocking ast to client2. 2. At the same time, client2 tries to unlink the striped dir (rm -rf striped_dir), and during lookup, it will hold the master inode of the striped directory, whose inode state is NEW, then tries to revalidate all of its slaves, (ll_prep_inode()->ll_iget()->ll_read_inode2()-> ll_update_inode().). And it will be blocked on the server side because of 1. 3. Then the client get the blocking_ast request, cancel the lock, but being blocked by ilookup5 in ll_md_blocking_ast(), because the inode state is still NEW. Signed-off-by: wang di Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-5344 Reviewed-on: http://review.whamcloud.com/16066 Reviewed-by: John L. Hammond Reviewed-by: Lai Siyao Reviewed-by: James Simmons Reviewed-by: Oleg Drokin Signed-off-by: James Simmons Signed-off-by: Greg Kroah-Hartman --- drivers/staging/lustre/lustre/llite/namei.c | 36 ++++++++++++++++++--- 1 file changed, 32 insertions(+), 4 deletions(-) diff --git a/drivers/staging/lustre/lustre/llite/namei.c b/drivers/staging/lustre/lustre/llite/namei.c index 318cd5f3226e..b07079c4dda0 100644 --- a/drivers/staging/lustre/lustre/llite/namei.c +++ b/drivers/staging/lustre/lustre/llite/namei.c @@ -296,10 +296,38 @@ int ll_md_blocking_ast(struct ldlm_lock *lock, struct ldlm_lock_desc *desc, hash = cl_fid_build_ino(&lli->lli_pfid, ll_need_32bit_api(ll_i2sbi(inode))); - - master_inode = ilookup5(inode->i_sb, hash, - ll_test_inode_by_fid, - (void *)&lli->lli_pfid); + /* + * Do not lookup the inode with ilookup5, + * otherwise it will cause dead lock, + * + * 1. Client1 send chmod req to the MDT0, then + * on MDT0, it enqueues master and all of its + * slaves lock, (mdt_attr_set() -> + * mdt_lock_slaves()), after gets master and + * stripe0 lock, it will send the enqueue req + * (for stripe1) to MDT1, then MDT1 finds the + * lock has been granted to client2. Then MDT1 + * sends blocking ast to client2. + * + * 2. At the same time, client2 tries to unlink + * the striped dir (rm -rf striped_dir), and + * during lookup, it will hold the master inode + * of the striped directory, whose inode state + * is NEW, then tries to revalidate all of its + * slaves, (ll_prep_inode()->ll_iget()-> + * ll_read_inode2()-> ll_update_inode().). And + * it will be blocked on the server side because + * of 1. + * + * 3. Then the client get the blocking_ast req, + * cancel the lock, but being blocked if using + * ->ilookup5()), because master inode state is + * NEW. + */ + master_inode = ilookup5_nowait(inode->i_sb, + hash, + ll_test_inode_by_fid, + (void *)&lli->lli_pfid); if (master_inode) { ll_invalidate_negative_children(master_inode); iput(master_inode); -- 2.39.5