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Message-id: <174112490070.33508.15852253149143067890@noble.neil.brown.name>
Date: Wed, 05 Mar 2025 08:48:20 +1100
From: "NeilBrown" <neilb@...e.de>
To: "Miklos Szeredi" <miklos@...redi.hu>
Cc: "Alexander Viro" <viro@...iv.linux.org.uk>,
"Christian Brauner" <brauner@...nel.org>, "Jan Kara" <jack@...e.cz>,
"Chuck Lever" <chuck.lever@...cle.com>, "Jeff Layton" <jlayton@...nel.org>,
"Trond Myklebust" <trondmy@...nel.org>, "Anna Schumaker" <anna@...nel.org>,
linux-nfs@...r.kernel.org, "Ilya Dryomov" <idryomov@...il.com>,
"Xiubo Li" <xiubli@...hat.com>, ceph-devel@...r.kernel.org,
linux-fsdevel@...r.kernel.org, "Richard Weinberger" <richard@....at>,
"Anton Ivanov" <anton.ivanov@...bridgegreys.com>,
"Johannes Berg" <johannes@...solutions.net>, linux-um@...ts.infradead.org,
linux-kernel@...r.kernel.org
Subject: [PATCH 4/6 - REVISED] fuse: return correct dentry for ->mkdir
Subject: [PATCH] fuse: return correct dentry for ->mkdir
fuse already uses d_splice_alias() to ensure an appropriate dentry is
found for a newly created dentry. Now that ->mkdir can return that
dentry we do so.
This requires changing create_new_entry() to return a dentry and
handling that change in all callers.
Note that when create_new_entry() is asked to create anything other than
a directory we can be sure it will NOT return an alternate dentry as
d_splice_alias() only returns an alternate dentry for directories.
So we don't need to check for that case when passing one the result.
Reviewed-by: Jeff Layton <jlayton@...nel.org>
Signed-off-by: NeilBrown <neilb@...e.de>
---
fs/fuse/dir.c | 48 +++++++++++++++++++++++++++++++-----------------
1 file changed, 31 insertions(+), 17 deletions(-)
Thanks for the suggestion Miklos - this looks much better.
Christian: could you please replace the fuse patch in your tree
with this version? Thanks.
NeilBrown
diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index d0289ce068ba..fa8f1141ea74 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -781,9 +781,9 @@ static int fuse_atomic_open(struct inode *dir, struct dentry *entry,
/*
* Code shared between mknod, mkdir, symlink and link
*/
-static int create_new_entry(struct mnt_idmap *idmap, struct fuse_mount *fm,
- struct fuse_args *args, struct inode *dir,
- struct dentry *entry, umode_t mode)
+static struct dentry *create_new_entry(struct mnt_idmap *idmap, struct fuse_mount *fm,
+ struct fuse_args *args, struct inode *dir,
+ struct dentry *entry, umode_t mode)
{
struct fuse_entry_out outarg;
struct inode *inode;
@@ -792,11 +792,11 @@ static int create_new_entry(struct mnt_idmap *idmap, struct fuse_mount *fm,
struct fuse_forget_link *forget;
if (fuse_is_bad(dir))
- return -EIO;
+ return ERR_PTR(-EIO);
forget = fuse_alloc_forget();
if (!forget)
- return -ENOMEM;
+ return ERR_PTR(-ENOMEM);
memset(&outarg, 0, sizeof(outarg));
args->nodeid = get_node_id(dir);
@@ -826,29 +826,43 @@ static int create_new_entry(struct mnt_idmap *idmap, struct fuse_mount *fm,
&outarg.attr, ATTR_TIMEOUT(&outarg), 0, 0);
if (!inode) {
fuse_queue_forget(fm->fc, forget, outarg.nodeid, 1);
- return -ENOMEM;
+ return ERR_PTR(-ENOMEM);
}
kfree(forget);
d_drop(entry);
d = d_splice_alias(inode, entry);
if (IS_ERR(d))
- return PTR_ERR(d);
+ return d;
- if (d) {
+ if (d)
fuse_change_entry_timeout(d, &outarg);
- dput(d);
- } else {
+ else
fuse_change_entry_timeout(entry, &outarg);
- }
fuse_dir_changed(dir);
- return 0;
+ return d;
out_put_forget_req:
if (err == -EEXIST)
fuse_invalidate_entry(entry);
kfree(forget);
- return err;
+ return ERR_PTR(err);
+}
+
+static int create_new_nondir(struct mnt_idmap *idmap, struct fuse_mount *fm,
+ struct fuse_args *args, struct inode *dir,
+ struct dentry *entry, umode_t mode)
+{
+ /*
+ * Note that when creating anything other than a directory we
+ * can be sure create_new_entry() will NOT return an alternate
+ * dentry as d_splice_alias() only returns an alternate dentry
+ * for directories. So we don't need to check for that case
+ * when passing back the result.
+ */
+ WARN_ON_ONCE(S_ISDIR(mode));
+
+ return PTR_ERR(create_new_entry(idmap, fm, args, dir, entry, mode));
}
static int fuse_mknod(struct mnt_idmap *idmap, struct inode *dir,
@@ -871,7 +885,7 @@ static int fuse_mknod(struct mnt_idmap *idmap, struct inode *dir,
args.in_args[0].value = &inarg;
args.in_args[1].size = entry->d_name.len + 1;
args.in_args[1].value = entry->d_name.name;
- return create_new_entry(idmap, fm, &args, dir, entry, mode);
+ return create_new_nondir(idmap, fm, &args, dir, entry, mode);
}
static int fuse_create(struct mnt_idmap *idmap, struct inode *dir,
@@ -917,7 +931,7 @@ static struct dentry *fuse_mkdir(struct mnt_idmap *idmap, struct inode *dir,
args.in_args[0].value = &inarg;
args.in_args[1].size = entry->d_name.len + 1;
args.in_args[1].value = entry->d_name.name;
- return ERR_PTR(create_new_entry(idmap, fm, &args, dir, entry, S_IFDIR));
+ return create_new_entry(idmap, fm, &args, dir, entry, S_IFDIR);
}
static int fuse_symlink(struct mnt_idmap *idmap, struct inode *dir,
@@ -934,7 +948,7 @@ static int fuse_symlink(struct mnt_idmap *idmap, struct inode *dir,
args.in_args[1].value = entry->d_name.name;
args.in_args[2].size = len;
args.in_args[2].value = link;
- return create_new_entry(idmap, fm, &args, dir, entry, S_IFLNK);
+ return create_new_nondir(idmap, fm, &args, dir, entry, S_IFLNK);
}
void fuse_flush_time_update(struct inode *inode)
@@ -1131,7 +1145,7 @@ static int fuse_link(struct dentry *entry, struct inode *newdir,
args.in_args[0].value = &inarg;
args.in_args[1].size = newent->d_name.len + 1;
args.in_args[1].value = newent->d_name.name;
- err = create_new_entry(&invalid_mnt_idmap, fm, &args, newdir, newent, inode->i_mode);
+ err = create_new_nondir(&invalid_mnt_idmap, fm, &args, newdir, newent, inode->i_mode);
if (!err)
fuse_update_ctime_in_cache(inode);
else if (err == -EINTR)
--
2.48.1
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