From: Chen Linxuan <chenlinxuan@xxxxxxxxxxxxx> This commit add fuse connection device id and backing_id, if any, to fdinfo of opened fuse files. Related discussions can be found at links below. Link: https://lore.kernel.org/all/CAOQ4uxgS3OUy9tpphAJKCQFRAn2zTERXXa0QN_KvP6ZOe2KVBw@xxxxxxxxxxxxxx/ Cc: Amir Goldstein <amir73il@xxxxxxxxx> Signed-off-by: Chen Linxuan <chenlinxuan@xxxxxxxxxxxxx> --- 1. I wonder if we should display fuse connection device id here. 2. I don't think using idr_for_each_entry is a good idea. But I failed to find another way to get backing_id of fuse_backing effectively. --- fs/fuse/file.c | 34 ++++++++++++++++++++++++++++++++++ 1 file changed, 34 insertions(+) diff --git a/fs/fuse/file.c b/fs/fuse/file.c index 754378dd9f7159f20fde6376962d45c4c706b868..5cfb806aa5cd22c57814168eb33de77c6f213da0 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 +3394,35 @@ 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 *m, struct file *f) +{ + struct fuse_file *ff = f->private_data; + struct fuse_conn *fc = ff->fm->fc; + struct fuse_inode *fi = get_fuse_inode(file_inode(f)); + + seq_printf(m, "fuse_conn:\t%u\n", fc->dev); + +#ifdef CONFIG_FUSE_PASSTHROUGH + struct fuse_backing *fb; + struct fuse_backing *backing; + int backing_id; + + if (ff->open_flags & FOPEN_PASSTHROUGH) { + fb = fuse_inode_backing(fi); + if (fb) { + rcu_read_lock(); + idr_for_each_entry(&fc->backing_files_map, backing, backing_id) { + if (backing == fb) { + seq_printf(m, "fuse_backing_id:\t%d\n", backing_id); + break; + } + } + rcu_read_unlock(); + } + } +#endif +} + static const struct file_operations fuse_file_operations = { .llseek = fuse_file_llseek, .read_iter = fuse_file_read_iter, @@ -3411,6 +3442,9 @@ 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
