c/mirror_zfs
1
0
Fork 0
mirror of https://git.proxmox.com/git/mirror_zfs.git synced 2026-05-22 02:27:36 +03:00
Code Issues Packages Projects Releases Wiki Activity

Fixes for procfs files backed by linked lists

Browse Source 
There are some issues with the way the seq_file interface is implemented
for kstats backed by linked lists (zfs_dbgmsgs and certain per-pool
debugging info):

* We don't account for the fact that seq_file sometimes visits a node
  multiple times, which results in missing messages when read through
  procfs.
* We don't keep separate state for each reader of a file, so concurrent
  readers will receive incorrect results.
* We don't account for the fact that entries may have been removed from
  the list between read syscalls, so reading from these files in procfs
  can cause the system to crash.

This change fixes these issues and adds procfs_list, a wrapper around a
linked list which abstracts away the details of implementing the
seq_file interface for a list and exposing the contents of the list
through procfs.

Reviewed by: Don Brady <don.brady@delphix.com>
Reviewed-by: Serapheim Dimitropoulos <serapheim@delphix.com>
Reviewed by: Brad Lewis <brad.lewis@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: John Gallagher <john.gallagher@delphix.com>
External-issue: LX-1211
Closes #7819
This commit is contained in:
John Gallagher
2018-09-26 11:08:12 -07:00
committed by Brian Behlendorf
parent 3ed2fbcc1c
commit d12614521a
24 changed files with 1094 additions and 566 deletions
Download Patch File Download Diff File Expand all files Collapse all files
lib/libzpool/kernel.c
+51
View File
@@ -424,6 +424,57 @@ cv_broadcast(kcondvar_t *cv)
VERIFY0(pthread_cond_broadcast(cv));
}
/*
* =========================================================================
* procfs list
* =========================================================================
*/
void
seq_printf(struct seq_file *m, const char *fmt, ...)
{}
void
procfs_list_install(const char *module,
const char *name,
procfs_list_t *procfs_list,
int (*show)(struct seq_file *f, void *p),
int (*show_header)(struct seq_file *f),
int (*clear)(procfs_list_t *procfs_list),
size_t procfs_list_node_off)
{
mutex_init(&procfs_list->pl_lock, NULL, MUTEX_DEFAULT, NULL);
list_create(&procfs_list->pl_list,
procfs_list_node_off + sizeof (procfs_list_node_t),
procfs_list_node_off + offsetof(procfs_list_node_t, pln_link));
procfs_list->pl_next_id = 1;
procfs_list->pl_node_offset = procfs_list_node_off;
}
void
procfs_list_uninstall(procfs_list_t *procfs_list)
{}
void
procfs_list_destroy(procfs_list_t *procfs_list)
{
ASSERT(list_is_empty(&procfs_list->pl_list));
list_destroy(&procfs_list->pl_list);
mutex_destroy(&procfs_list->pl_lock);
}
#define NODE_ID(procfs_list, obj) \
(((procfs_list_node_t *)(((char *)obj) + \
(procfs_list)->pl_node_offset))->pln_id)
void
procfs_list_add(procfs_list_t *procfs_list, void *p)
{
ASSERT(MUTEX_HELD(&procfs_list->pl_lock));
NODE_ID(procfs_list, p) = procfs_list->pl_next_id++;
list_insert_tail(&procfs_list->pl_list, p);
}
/*
* =========================================================================
* vnode operations