[PATCH 5.17 078/219] cachefiles: unmark inode in use in error path

Greg Kroah-Hartman
2022-04-18T12:22:58Z

From: Jeffle Xu <jefflexu@linux.alibaba.com>

[ Upstream commit ea5dc046127e857a7873ae55fd57c866e9e86fb2 ]

Unmark inode in use if error encountered. If the in-use flag leakage
occurs in cachefiles_open_file(), Cachefiles will complain "Inode
already in use" when later another cookie with the same index key is
looked up.

If the in-use flag leakage occurs in cachefiles_create_tmpfile(), though
the "Inode already in use" warning won't be triggered, fix the leakage
anyway.

Reported-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Fixes: 1f08c925e7a3 ("cachefiles: Implement backing file wrangling")
Signed-off-by: Jeffle Xu <jefflexu@linux.alibaba.com>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: linux-cachefs@redhat.com
Link: https://listman.redhat.com/archives/linux-cachefs/2022-March/006615.html # v1
Link: https://listman.redhat.com/archives/linux-cachefs/2022-March/006618.html # v2
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/cachefiles/namei.c | 33 ++++++++++++++++++++++++---------
1 file changed, 24 insertions(+), 9 deletions(-)

diff --git a/fs/cachefiles/namei.c b/fs/cachefiles/namei.c
index f256c8aff7bb..ca9f3e4ec4b3 100644
--- a/fs/cachefiles/namei.c
+++ b/fs/cachefiles/namei.c
@@ -57,6 +57,16 @@ static void __cachefiles_unmark_inode_in_use(struct cachefiles_object *object,
trace_cachefiles_mark_inactive(object, inode);
}

+static void cachefiles_do_unmark_inode_in_use(struct cachefiles_object *object,
+ struct dentry *dentry)
+{
+ struct inode *inode = d_backing_inode(dentry);
+
+ inode_lock(inode);
+ __cachefiles_unmark_inode_in_use(object, dentry);
+ inode_unlock(inode);
+}
+
/*
* Unmark a backing inode and tell cachefilesd that there's something that can
* be culled.
@@ -68,9 +78,7 @@ void cachefiles_unmark_inode_in_use(struct cachefiles_object *object,
struct inode *inode = file_inode(file);

if (inode) {
- inode_lock(inode);
- __cachefiles_unmark_inode_in_use(object, file->f_path.dentry);
- inode_unlock(inode);
+ cachefiles_do_unmark_inode_in_use(object, file->f_path.dentry);

if (!test_bit(CACHEFILES_OBJECT_USING_TMPFILE, &object->flags)) {
atomic_long_add(inode->i_blocks, &cache->b_released);
@@ -484,7 +492,7 @@ struct file *cachefiles_create_tmpfile(struct cachefiles_object *object)
object, d_backing_inode(path.dentry), ret,
cachefiles_trace_trunc_error);
file = ERR_PTR(ret);
- goto out_dput;
+ goto out_unuse;
}
}

@@ -494,15 +502,20 @@ struct file *cachefiles_create_tmpfile(struct cachefiles_object *object)
trace_cachefiles_vfs_error(object, d_backing_inode(path.dentry),
PTR_ERR(file),
cachefiles_trace_open_error);
- goto out_dput;
+ goto out_unuse;
}
if (unlikely(!file->f_op->read_iter) ||
unlikely(!file->f_op->write_iter)) {
fput(file);
pr_notice("Cache does not support read_iter and write_iter\n");
file = ERR_PTR(-EINVAL);
+ goto out_unuse;
}

+ goto out_dput;
+
+out_unuse:
+ cachefiles_do_unmark_inode_in_use(object, path.dentry);
out_dput:
dput(path.dentry);
out:
@@ -590,14 +603,16 @@ static bool cachefiles_open_file(struct cachefiles_object *object,
check_failed:
fscache_cookie_lookup_negative(object->cookie);
cachefiles_unmark_inode_in_use(object, file);
- if (ret == -ESTALE) {
- fput(file);
- dput(dentry);
+ fput(file);
+ dput(dentry);
+ if (ret == -ESTALE)
return cachefiles_create_file(object);
- }
+ return false;
+
error_fput:
fput(file);
error:
+ cachefiles_do_unmark_inode_in_use(object, dentry);
dput(dentry);
return false;
}
--
2.35.1