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nfsd: use fsnotify group lock helpers

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[ 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>
This commit is contained in:
Amir Goldstein 2022-04-22 15:03:20 +03:00 • committed by Ksawlii
parent e26b208539
commit 924ad2359b
1 changed files with 7 additions and 6 deletions
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13
fs/nfsd/filecache.c
View file

@ -118,14 +118,14 @@ nfsd_file_mark_find_or_create(struct nfsd_file *nf)
struct inode *inode = nf->nf_inode; struct inode *inode = nf->nf_inode;
do { do {
mutex_lock(&nfsd_file_fsnotify_group->mark_mutex); fsnotify_group_lock(nfsd_file_fsnotify_group);
mark = fsnotify_find_mark(&inode->i_fsnotify_marks, mark = fsnotify_find_mark(&inode->i_fsnotify_marks,
nfsd_file_fsnotify_group); nfsd_file_fsnotify_group);
if (mark) { if (mark) {
nfm = nfsd_file_mark_get(container_of(mark, nfm = nfsd_file_mark_get(container_of(mark,
struct nfsd_file_mark, struct nfsd_file_mark,
nfm_mark)); nfm_mark));
mutex_unlock(&nfsd_file_fsnotify_group->mark_mutex); fsnotify_group_unlock(nfsd_file_fsnotify_group);
if (nfm) { if (nfm) {
fsnotify_put_mark(mark); fsnotify_put_mark(mark);
break; break;
@ -133,8 +133,9 @@ nfsd_file_mark_find_or_create(struct nfsd_file *nf)
/* Avoid soft lockup race with nfsd_file_mark_put() */ /* Avoid soft lockup race with nfsd_file_mark_put() */
fsnotify_destroy_mark(mark, nfsd_file_fsnotify_group); fsnotify_destroy_mark(mark, nfsd_file_fsnotify_group);
fsnotify_put_mark(mark); fsnotify_put_mark(mark);
} else } else {
mutex_unlock(&nfsd_file_fsnotify_group->mark_mutex); fsnotify_group_unlock(nfsd_file_fsnotify_group);
}
/* allocate a new nfm */ /* allocate a new nfm */
new = kmem_cache_alloc(nfsd_file_mark_slab, GFP_KERNEL); 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, nfsd_file_fsnotify_group = fsnotify_alloc_group(&nfsd_file_fsnotify_ops,
0); FSNOTIFY_GROUP_NOFS);
if (IS_ERR(nfsd_file_fsnotify_group)) { if (IS_ERR(nfsd_file_fsnotify_group)) {
pr_err("nfsd: unable to create fsnotify group: %ld\n", pr_err("nfsd: unable to create fsnotify group: %ld\n",
PTR_ERR(nfsd_file_fsnotify_group)); PTR_ERR(nfsd_file_fsnotify_group));