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netfs: Add a procfile to list in-progress requests

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Add a procfile, /proc/fs/netfs/requests, to list in-progress netfslib I/O
requests.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
cc: linux-fsdevel@vger.kernel.org
cc: linux-mm@kvack.org
This commit is contained in:
David Howells 2022-03-04 10:34:27 +00:00
parent c9c4ff12df
commit 87b57a0489
4 changed files with 98 additions and 3 deletions
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22
fs/netfs/internal.h
View file

@ -33,6 +33,28 @@ int netfs_begin_read(struct netfs_io_request *rreq, bool sync);
* main.c
*/
extern unsigned int netfs_debug;
extern struct list_head netfs_io_requests;
extern spinlock_t netfs_proc_lock;
#ifdef CONFIG_PROC_FS
static inline void netfs_proc_add_rreq(struct netfs_io_request *rreq)
{
spin_lock(&netfs_proc_lock);
list_add_tail_rcu(&rreq->proc_link, &netfs_io_requests);
spin_unlock(&netfs_proc_lock);
}
static inline void netfs_proc_del_rreq(struct netfs_io_request *rreq)
{
if (!list_empty(&rreq->proc_link)) {
spin_lock(&netfs_proc_lock);
list_del_rcu(&rreq->proc_link);
spin_unlock(&netfs_proc_lock);
}
}
#else
static inline void netfs_proc_add_rreq(struct netfs_io_request *rreq) {}
static inline void netfs_proc_del_rreq(struct netfs_io_request *rreq) {}
#endif
/*
* objects.c

69
fs/netfs/main.c
View file

@ -21,13 +21,80 @@ unsigned netfs_debug;
module_param_named(debug, netfs_debug, uint, S_IWUSR | S_IRUGO);
MODULE_PARM_DESC(netfs_debug, "Netfs support debugging mask");
#ifdef CONFIG_PROC_FS
LIST_HEAD(netfs_io_requests);
DEFINE_SPINLOCK(netfs_proc_lock);
static const char *netfs_origins[] = {
[NETFS_READAHEAD] = "RA",
[NETFS_READPAGE] = "RP",
[NETFS_READ_FOR_WRITE] = "RW",
};
/*
* Generate a list of I/O requests in /proc/fs/netfs/requests
*/
static int netfs_requests_seq_show(struct seq_file *m, void *v)
{
struct netfs_io_request *rreq;
if (v == &netfs_io_requests) {
seq_puts(m,
"REQUEST OR REF FL ERR OPS COVERAGE\n"
"======== == === == ==== === =========\n"
);
return 0;
}
rreq = list_entry(v, struct netfs_io_request, proc_link);
seq_printf(m,
"%08x %s %3d %2lx %4d %3d @%04llx %zx/%zx",
rreq->debug_id,
netfs_origins[rreq->origin],
refcount_read(&rreq->ref),
rreq->flags,
rreq->error,
atomic_read(&rreq->nr_outstanding),
rreq->start, rreq->submitted, rreq->len);
seq_putc(m, '\n');
return 0;
}
static void *netfs_requests_seq_start(struct seq_file *m, loff_t *_pos)
__acquires(rcu)
{
rcu_read_lock();
return seq_list_start_head(&netfs_io_requests, *_pos);
}
static void *netfs_requests_seq_next(struct seq_file *m, void *v, loff_t *_pos)
{
return seq_list_next(v, &netfs_io_requests, _pos);
}
static void netfs_requests_seq_stop(struct seq_file *m, void *v)
__releases(rcu)
{
rcu_read_unlock();
}
static const struct seq_operations netfs_requests_seq_ops = {
.start = netfs_requests_seq_start,
.next = netfs_requests_seq_next,
.stop = netfs_requests_seq_stop,
.show = netfs_requests_seq_show,
};
#endif /* CONFIG_PROC_FS */
static int __init netfs_init(void)
{
int ret = -ENOMEM;
if (!proc_mkdir("fs/netfs", NULL))
goto error;
if (!proc_create_seq("fs/netfs/requests", S_IFREG | 0444, NULL,
&netfs_requests_seq_ops))
goto error_proc;
#ifdef CONFIG_FSCACHE_STATS
if (!proc_create_single("fs/netfs/stats", S_IFREG | 0444, NULL,
netfs_stats_show))

4
fs/netfs/objects.c
View file

@ -45,6 +45,7 @@ struct netfs_io_request *netfs_alloc_request(struct address_space *mapping,
}
}
netfs_proc_add_rreq(rreq);
netfs_stat(&netfs_n_rh_rreq);
return rreq;
}
@ -76,12 +77,13 @@ static void netfs_free_request(struct work_struct *work)
container_of(work, struct netfs_io_request, work);
trace_netfs_rreq(rreq, netfs_rreq_trace_free);
netfs_proc_del_rreq(rreq);
netfs_clear_subrequests(rreq, false);
if (rreq->netfs_ops->free_request)
rreq->netfs_ops->free_request(rreq);
if (rreq->cache_resources.ops)
rreq->cache_resources.ops->end_operation(&rreq->cache_resources);
kfree(rreq);
kfree_rcu(rreq, rcu);
netfs_stat_d(&netfs_n_rh_rreq);
}

6
include/linux/netfs.h
View file

@ -175,10 +175,14 @@ enum netfs_io_origin {
* operations to a variety of data stores and then stitch the result together.
*/
struct netfs_io_request {
struct work_struct work;
union {
struct work_struct work;
struct rcu_head rcu;
};
struct inode *inode; /* The file being accessed */
struct address_space *mapping; /* The mapping being accessed */
struct netfs_cache_resources cache_resources;
struct list_head proc_link; /* Link in netfs_iorequests */
struct list_head subrequests; /* Contributory I/O operations */
void *netfs_priv; /* Private data for the netfs */
unsigned int debug_id;