[PATCH] fs: fix automount when last filename component is a automountpoint

[PATCH] fs: fix automount when last filename component is a automountpoint

[Sascha Hauer]

When opening a directory in openat() as indicated with the O_DIRECTORY
flag, pass the LOOKUP_DIRECTOY flag to filename_lookup() to make sure
the target is actually a directory. By doing this we can skip the check
afterwards.

filename_lookup() only triggers the automount on the last component when
the LOOKUP_DIRECTORY flag is set, so with this change when /mnt/mmc2.3/
is a automountpoint a

stat /mnt/mmc2.3/

now triggers automounting. This also fixes tab completion with
"ls /mnt/mmc2.3/<tab>" which previously didn't trigger autmounting.

Fixes: a1da0079d1 ("fs: implement opendir in terms of fdopendir")
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
---
 fs/fs.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/fs/fs.c b/fs/fs.c
index 528299e039..d884726187 100644
--- a/fs/fs.c
+++ b/fs/fs.c
@@ -2680,7 +2680,12 @@ int openat(int dirfd, const char *pathname, int flags)
 	}
 
 	if (!(flags & O_CREAT) || error == -EEXIST) {
-		error = filename_lookup(dirfd, getname(pathname), LOOKUP_FOLLOW, &path);
+		unsigned f = LOOKUP_FOLLOW;
+
+		if (flags & O_DIRECTORY)
+			f |= LOOKUP_DIRECTORY;
+
+		error = filename_lookup(dirfd, getname(pathname), f, &path);
 		dentry = path.dentry;
 	}
 
@@ -2710,9 +2715,6 @@ int openat(int dirfd, const char *pathname, int flags)
 		}
 
 		flags |= O_DIRECTORY;
-	} else if (flags & O_DIRECTORY) {
-		error = -ENOTDIR;
-		goto out1;
 	}
 
 	inode = d_inode(dentry);
-- 
2.47.3

Re: [PATCH] fs: fix automount when last filename component is a automountpoint

[Ahmad Fatoum]

Hi,

On 12/2/25 10:22 AM, Sascha Hauer wrote:
> When opening a directory in openat() as indicated with the O_DIRECTORY
> flag, pass the LOOKUP_DIRECTOY flag to filename_lookup() to make sure
> the target is actually a directory. By doing this we can skip the check
> afterwards.
> 
> filename_lookup() only triggers the automount on the last component when
> the LOOKUP_DIRECTORY flag is set, so with this change when /mnt/mmc2.3/
> is a automountpoint a
> 
> stat /mnt/mmc2.3/
> 
> now triggers automounting. This also fixes tab completion with
> "ls /mnt/mmc2.3/<tab>" which previously didn't trigger autmounting.
> 
> Fixes: a1da0079d1 ("fs: implement opendir in terms of fdopendir")
> Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

Reviewed-by: Ahmad Fatoum <a.fatoum@pengutronix.de>

Thanks for debugging!
Ahmad

> ---
>  fs/fs.c | 10 ++++++----
>  1 file changed, 6 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/fs.c b/fs/fs.c
> index 528299e039..d884726187 100644
> --- a/fs/fs.c
> +++ b/fs/fs.c
> @@ -2680,7 +2680,12 @@ int openat(int dirfd, const char *pathname, int flags)
>  	}
>  
>  	if (!(flags & O_CREAT) || error == -EEXIST) {
> -		error = filename_lookup(dirfd, getname(pathname), LOOKUP_FOLLOW, &path);
> +		unsigned f = LOOKUP_FOLLOW;
> +
> +		if (flags & O_DIRECTORY)
> +			f |= LOOKUP_DIRECTORY;
> +
> +		error = filename_lookup(dirfd, getname(pathname), f, &path);
>  		dentry = path.dentry;
>  	}
>  
> @@ -2710,9 +2715,6 @@ int openat(int dirfd, const char *pathname, int flags)
>  		}
>  
>  		flags |= O_DIRECTORY;
> -	} else if (flags & O_DIRECTORY) {
> -		error = -ENOTDIR;
> -		goto out1;
>  	}
>  
>  	inode = d_inode(dentry);

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