On Fri, May 9, 2025 at 2:34 PM Chen Linxuan via B4 Relay <devnull+chenlinxuan.uniontech.com@xxxxxxxxxx> wrote: > > From: Chen Linxuan <chenlinxuan@xxxxxxxxxxxxx> > > This commit add fuse connection device id, open_flags and backing > files, to fdinfo of opened fuse files. > > Related discussions can be found at links below. > > Link: https://lore.kernel.org/all/CAOQ4uxgS3OUy9tpphAJKCQFRAn2zTERXXa0QN_KvP6ZOe2KVBw@xxxxxxxxxxxxxx/ > Link: https://lore.kernel.org/all/CAOQ4uxgkg0uOuAWO2wOPNkMmD9wqd5wMX+gTfCT-zVHBC8CkZg@xxxxxxxxxxxxxx/ > Cc: Amir Goldstein <amir73il@xxxxxxxxx> > Signed-off-by: Chen Linxuan <chenlinxuan@xxxxxxxxxxxxx> > --- > fs/fuse/file.c | 20 ++++++++++++++++++++ > 1 file changed, 20 insertions(+) > > diff --git a/fs/fuse/file.c b/fs/fuse/file.c > index 754378dd9f7159f20fde6376962d45c4c706b868..1e54965780e9d625918c22a3dea48ba5a9a5ed1b 100644 > --- a/fs/fuse/file.c > +++ b/fs/fuse/file.c > @@ -8,6 +8,8 @@ > > #include "fuse_i.h" > > +#include "linux/idr.h" > +#include "linux/rcupdate.h" > #include <linux/pagemap.h> > #include <linux/slab.h> > #include <linux/kernel.h> > @@ -3392,6 +3394,21 @@ static ssize_t fuse_copy_file_range(struct file *src_file, loff_t src_off, > return ret; > } > > +static void fuse_file_show_fdinfo(struct seq_file *seq, struct file *f) > +{ > + struct fuse_file *ff = f->private_data; > + struct fuse_conn *fc = ff->fm->fc; > + struct file *backing_file = fuse_file_passthrough(ff); > + > + seq_printf(seq, "fuse conn:%u open_flags:%u\n", fc->dev, ff->open_flags); Note: The fc->dev is already accessible to userspace. The mnt_id field in /proc/PID/fdinfo/FD references a mount, which can be found in /proc/PID/mountinfo. And this file includes the device ID. > + > + if (backing_file) { > + seq_puts(seq, "fuse backing_file: "); > + seq_file_path(seq, backing_file, " \t\n\\"); > + seq_puts(seq, "\n"); > + } > +} > + > static const struct file_operations fuse_file_operations = { > .llseek = fuse_file_llseek, > .read_iter = fuse_file_read_iter, > @@ -3411,6 +3428,9 @@ static const struct file_operations fuse_file_operations = { > .poll = fuse_file_poll, > .fallocate = fuse_file_fallocate, > .copy_file_range = fuse_copy_file_range, > +#ifdef CONFIG_PROC_FS > + .show_fdinfo = fuse_file_show_fdinfo, > +#endif > }; > > static const struct address_space_operations fuse_file_aops = { > > -- > 2.43.0 > > > >
