From ee389fca75e4a4807b37f9619e008542b685729f Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Mon, 4 Oct 2021 15:37:42 -0400 Subject: [PATCH] NFS: Fix up commit deadlocks commit 133a48abf6ecc535d7eddc6da1c3e4c972445882 upstream. If O_DIRECT bumps the commit_info rpcs_out field, then that could lead to fsync() hangs. The fix is to ensure that O_DIRECT calls nfs_commit_end(). Fixes: 723c921e7dfc ("sched/wait, fs/nfs: Convert wait_on_atomic_t() usage to the new wait_var_event() API") Signed-off-by: Trond Myklebust Signed-off-by: Chanho Min Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- fs/nfs/direct.c | 2 +- fs/nfs/write.c | 9 ++++++--- include/linux/nfs_fs.h | 1 + 3 files changed, 8 insertions(+), 4 deletions(-) diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c index 0682037f972b..32dc176ea1ab 100644 --- a/fs/nfs/direct.c +++ b/fs/nfs/direct.c @@ -700,7 +700,7 @@ static void nfs_direct_commit_complete(struct nfs_commit_data *data) nfs_unlock_and_release_request(req); } - if (atomic_dec_and_test(&cinfo.mds->rpcs_out)) + if (nfs_commit_end(cinfo.mds)) nfs_direct_write_complete(dreq); } diff --git a/fs/nfs/write.c b/fs/nfs/write.c index 10ce264a6456..c9895316fc07 100644 --- a/fs/nfs/write.c +++ b/fs/nfs/write.c @@ -1658,10 +1658,13 @@ static void nfs_commit_begin(struct nfs_mds_commit_info *cinfo) atomic_inc(&cinfo->rpcs_out); } -static void nfs_commit_end(struct nfs_mds_commit_info *cinfo) +bool nfs_commit_end(struct nfs_mds_commit_info *cinfo) { - if (atomic_dec_and_test(&cinfo->rpcs_out)) + if (atomic_dec_and_test(&cinfo->rpcs_out)) { wake_up_var(&cinfo->rpcs_out); + return true; + } + return false; } void nfs_commitdata_release(struct nfs_commit_data *data) @@ -1756,6 +1759,7 @@ void nfs_init_commit(struct nfs_commit_data *data, data->res.fattr = &data->fattr; data->res.verf = &data->verf; nfs_fattr_init(&data->fattr); + nfs_commit_begin(cinfo->mds); } EXPORT_SYMBOL_GPL(nfs_init_commit); @@ -1801,7 +1805,6 @@ nfs_commit_list(struct inode *inode, struct list_head *head, int how, /* Set up the argument struct */ nfs_init_commit(data, head, NULL, cinfo); - atomic_inc(&cinfo->mds->rpcs_out); return nfs_initiate_commit(NFS_CLIENT(inode), data, NFS_PROTO(inode), data->mds_ops, how, 0); } diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h index 49cf5c855cbe..a96b116cc922 100644 --- a/include/linux/nfs_fs.h +++ b/include/linux/nfs_fs.h @@ -549,6 +549,7 @@ extern int nfs_wb_page_cancel(struct inode *inode, struct page* page); extern int nfs_commit_inode(struct inode *, int); extern struct nfs_commit_data *nfs_commitdata_alloc(bool never_fail); extern void nfs_commit_free(struct nfs_commit_data *data); +bool nfs_commit_end(struct nfs_mds_commit_info *cinfo); static inline int nfs_have_writebacks(struct inode *inode)