[RFC PATCH 1/2] fuse: revalidate: move lookup into a separate function

From: Krister Johansen
Date: Mon Jul 10 2023 - 21:45:59 EST


If this refactoring seems cumbersome, it's because the goal is to move
the lookup parts of fuse_dentry_revalidate into a common function. This
function will be used elsewhere in a separate commit. In the meantime,
the new function fuse_dentry_revalidate_lookup is responsible for just
the lookup and validation portions of the revalidate dance. The
fuse_dentry_revalidate function retains the responsibility for
invalidating and mutating any state associated with the origial
fuse_inode and dentry.

Signed-off-by: Krister Johansen <kjlx@xxxxxxxxxxxxxxxxxx>
---
fs/fuse/dir.c | 87 +++++++++++++++++++++++++++++++++++----------------
1 file changed, 60 insertions(+), 27 deletions(-)

diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index f67bef9d83c4..bdf5526a0733 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -193,6 +193,59 @@ static void fuse_lookup_init(struct fuse_conn *fc, struct fuse_args *args,
args->out_args[0].value = outarg;
}

+static int fuse_dentry_revalidate_lookup(struct fuse_mount *fm,
+ struct dentry *entry,
+ struct inode *inode,
+ struct fuse_entry_out *outarg,
+ bool *lookedup)
+{
+ struct dentry *parent;
+ struct fuse_forget_link *forget;
+ struct fuse_inode *fi;
+ FUSE_ARGS(args);
+ int ret;
+
+ forget = fuse_alloc_forget();
+ ret = -ENOMEM;
+ if (!forget)
+ goto out;
+
+ parent = dget_parent(entry);
+ fuse_lookup_init(fm->fc, &args, get_node_id(d_inode(parent)),
+ &entry->d_name, outarg);
+ ret = fuse_simple_request(fm, &args);
+ dput(parent);
+
+ /* Zero nodeid is same as -ENOENT */
+ if (!ret && !outarg->nodeid)
+ ret = -ENOENT;
+ if (!ret) {
+ fi = get_fuse_inode(inode);
+ if (outarg->nodeid != get_node_id(inode) ||
+ (bool) IS_AUTOMOUNT(inode) != (bool) (outarg->attr.flags & FUSE_ATTR_SUBMOUNT)) {
+ fuse_queue_forget(fm->fc, forget,
+ outarg->nodeid, 1);
+ goto invalid;
+ }
+ *lookedup = true;
+ }
+ kfree(forget);
+ if (ret == -ENOMEM || ret == -EINTR)
+ goto out;
+ if (ret || fuse_invalid_attr(&outarg->attr) ||
+ fuse_stale_inode(inode, outarg->generation, &outarg->attr)) {
+ goto invalid;
+ }
+
+ ret = 1;
+out:
+ return ret;
+
+invalid:
+ ret = 0;
+ goto out;
+}
+
/*
* Check whether the dentry is still valid
*
@@ -216,9 +269,8 @@ static int fuse_dentry_revalidate(struct dentry *entry, unsigned int flags)
else if (time_before64(fuse_dentry_time(entry), get_jiffies_64()) ||
(flags & (LOOKUP_EXCL | LOOKUP_REVAL | LOOKUP_RENAME_TARGET))) {
struct fuse_entry_out outarg;
- FUSE_ARGS(args);
- struct fuse_forget_link *forget;
u64 attr_version;
+ bool lookedup = false;

/* For negative dentries, always do a fresh lookup */
if (!inode)
@@ -230,38 +282,19 @@ static int fuse_dentry_revalidate(struct dentry *entry, unsigned int flags)

fm = get_fuse_mount(inode);

- forget = fuse_alloc_forget();
- ret = -ENOMEM;
- if (!forget)
- goto out;
-
attr_version = fuse_get_attr_version(fm->fc);

- parent = dget_parent(entry);
- fuse_lookup_init(fm->fc, &args, get_node_id(d_inode(parent)),
- &entry->d_name, &outarg);
- ret = fuse_simple_request(fm, &args);
- dput(parent);
- /* Zero nodeid is same as -ENOENT */
- if (!ret && !outarg.nodeid)
- ret = -ENOENT;
- if (!ret) {
+ ret = fuse_dentry_revalidate_lookup(fm, entry, inode, &outarg,
+ &lookedup);
+ if (ret == -ENOMEM || ret == -EINTR)
+ goto out;
+ if (lookedup) {
fi = get_fuse_inode(inode);
- if (outarg.nodeid != get_node_id(inode) ||
- (bool) IS_AUTOMOUNT(inode) != (bool) (outarg.attr.flags & FUSE_ATTR_SUBMOUNT)) {
- fuse_queue_forget(fm->fc, forget,
- outarg.nodeid, 1);
- goto invalid;
- }
spin_lock(&fi->lock);
fi->nlookup++;
spin_unlock(&fi->lock);
}
- kfree(forget);
- if (ret == -ENOMEM || ret == -EINTR)
- goto out;
- if (ret || fuse_invalid_attr(&outarg.attr) ||
- fuse_stale_inode(inode, outarg.generation, &outarg.attr))
+ if (ret <= 0)
goto invalid;

forget_all_cached_acls(inode);
--
2.25.1