5.10-stable review patch. If anyone has any objections, please let me know.
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From: Amir Goldstein amir73il@gmail.com
[ Upstream commit b8962a9d8cc2d8c93362e2f684091c79f702f6f3 ]
Before commit 9542e6a643fc6 ("nfsd: Containerise filecache laundrette") nfsd would close open files in direct reclaim context and that could cause a deadlock when fsnotify mark allocation went into direct reclaim and nfsd shrinker tried to free existing fsnotify marks.
To avoid issues like this in future code, set the FSNOTIFY_GROUP_NOFS flag on nfsd fsnotify group to prevent going into direct reclaim from fsnotify_add_inode_mark().
Link: https://lore.kernel.org/r/20220422120327.3459282-10-amir73il@gmail.com Suggested-by: Jan Kara jack@suse.cz Link: https://lore.kernel.org/r/20220321112310.vpr7oxro2xkz5llh@quack3.lan/ Signed-off-by: Amir Goldstein amir73il@gmail.com Signed-off-by: Jan Kara jack@suse.cz Signed-off-by: Chuck Lever chuck.lever@oracle.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/nfsd/filecache.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-)
diff --git a/fs/nfsd/filecache.c b/fs/nfsd/filecache.c index 7ae2b6611fb29..7e99e75b75d73 100644 --- a/fs/nfsd/filecache.c +++ b/fs/nfsd/filecache.c @@ -118,14 +118,14 @@ nfsd_file_mark_find_or_create(struct nfsd_file *nf) struct inode *inode = nf->nf_inode;
do { - mutex_lock(&nfsd_file_fsnotify_group->mark_mutex); + fsnotify_group_lock(nfsd_file_fsnotify_group); mark = fsnotify_find_mark(&inode->i_fsnotify_marks, - nfsd_file_fsnotify_group); + nfsd_file_fsnotify_group); if (mark) { nfm = nfsd_file_mark_get(container_of(mark, struct nfsd_file_mark, nfm_mark)); - mutex_unlock(&nfsd_file_fsnotify_group->mark_mutex); + fsnotify_group_unlock(nfsd_file_fsnotify_group); if (nfm) { fsnotify_put_mark(mark); break; @@ -133,8 +133,9 @@ nfsd_file_mark_find_or_create(struct nfsd_file *nf) /* Avoid soft lockup race with nfsd_file_mark_put() */ fsnotify_destroy_mark(mark, nfsd_file_fsnotify_group); fsnotify_put_mark(mark); - } else - mutex_unlock(&nfsd_file_fsnotify_group->mark_mutex); + } else { + fsnotify_group_unlock(nfsd_file_fsnotify_group); + }
/* allocate a new nfm */ new = kmem_cache_alloc(nfsd_file_mark_slab, GFP_KERNEL); @@ -678,7 +679,7 @@ nfsd_file_cache_init(void) }
nfsd_file_fsnotify_group = fsnotify_alloc_group(&nfsd_file_fsnotify_ops, - 0); + FSNOTIFY_GROUP_NOFS); if (IS_ERR(nfsd_file_fsnotify_group)) { pr_err("nfsd: unable to create fsnotify group: %ld\n", PTR_ERR(nfsd_file_fsnotify_group));