From 9b101a73203faecdc6d466fe446d787bc341ee14 Mon Sep 17 00:00:00 2001 From: Brian Behlendorf Date: Fri, 22 Nov 2013 16:00:39 -0800 Subject: [PATCH] Clarify zpool_events_next() comment Due to the very poorly chosen argument name 'cleanup_fd' it was completely unclear that this file descriptor is used to track the current cursor location. When the file descriptor is created by opening ZFS_DEV a private cursor is created in the kernel for the returned file descriptor. Subsequent calls to zpool_events_next() and zpool_events_seek() then require the file descriptor as an argument to reposition the cursor. When the file descriptor is closed the kernel state tracking the cursor is destroyed. This patch contains no functional change, it just changes a few variable names and clarifies the documentation. Signed-off-by: Brian Behlendorf Signed-off-by: Chris Dunlap Issue #2 --- cmd/zpool/zpool_main.c | 10 +++++----- lib/libzfs/libzfs_pool.c | 20 ++++++++++---------- module/zfs/zfs_ioctl.c | 2 +- 3 files changed, 16 insertions(+), 16 deletions(-) diff --git a/cmd/zpool/zpool_main.c b/cmd/zpool/zpool_main.c index d095b15a5864..4254f9b4d7c5 100644 --- a/cmd/zpool/zpool_main.c +++ b/cmd/zpool/zpool_main.c @@ -5455,17 +5455,17 @@ static int zpool_do_events_next(ev_opts_t *opts) { nvlist_t *nvl; - int cleanup_fd, ret, dropped; + int zevent_fd, ret, dropped; - cleanup_fd = open(ZFS_DEV, O_RDWR); - VERIFY(cleanup_fd >= 0); + zevent_fd = open(ZFS_DEV, O_RDWR); + VERIFY(zevent_fd >= 0); if (!opts->scripted) (void) printf(gettext("%-30s %s\n"), "TIME", "CLASS"); while (1) { ret = zpool_events_next(g_zfs, &nvl, &dropped, - !!opts->follow, cleanup_fd); + !!opts->follow, zevent_fd); if (ret || nvl == NULL) break; @@ -5483,7 +5483,7 @@ zpool_do_events_next(ev_opts_t *opts) nvlist_free(nvl); } - VERIFY(0 == close(cleanup_fd)); + VERIFY(0 == close(zevent_fd)); return (ret); } diff --git a/lib/libzfs/libzfs_pool.c b/lib/libzfs/libzfs_pool.c index 1b8f3b63a82a..2054385b8d35 100644 --- a/lib/libzfs/libzfs_pool.c +++ b/lib/libzfs/libzfs_pool.c @@ -3783,25 +3783,25 @@ zpool_get_history(zpool_handle_t *zhp, nvlist_t **nvhisp) } /* - * Retrieve the next event. If there is a new event available 'nvp' will - * contain a newly allocated nvlist and 'dropped' will be set to the number - * of missed events since the last call to this function. When 'nvp' is - * set to NULL it indicates no new events are available. In either case - * the function returns 0 and it is up to the caller to free 'nvp'. In - * the case of a fatal error the function will return a non-zero value. - * When the function is called in blocking mode it will not return until - * a new event is available. + * Retrieve the next event given the passed 'zevent_fd' file descriptor. + * If there is a new event available 'nvp' will contain a newly allocated + * nvlist and 'dropped' will be set to the number of missed events since + * the last call to this function. When 'nvp' is set to NULL it indicates + * no new events are available. In either case the function returns 0 and + * it is up to the caller to free 'nvp'. In the case of a fatal error the + * function will return a non-zero value. When the function is called in + * blocking mode it will not return until a new event is available. */ int zpool_events_next(libzfs_handle_t *hdl, nvlist_t **nvp, - int *dropped, int block, int cleanup_fd) + int *dropped, int block, int zevent_fd) { zfs_cmd_t zc = {"\0"}; int error = 0; *nvp = NULL; *dropped = 0; - zc.zc_cleanup_fd = cleanup_fd; + zc.zc_cleanup_fd = zevent_fd; if (!block) zc.zc_guid = ZEVENT_NONBLOCK; diff --git a/module/zfs/zfs_ioctl.c b/module/zfs/zfs_ioctl.c index cd47790166f5..0dfda1abf77c 100644 --- a/module/zfs/zfs_ioctl.c +++ b/module/zfs/zfs_ioctl.c @@ -4860,11 +4860,11 @@ zfs_ioc_release(const char *pool, nvlist_t *holds, nvlist_t *errlist) /* * inputs: * zc_guid flags (ZEVENT_NONBLOCK) + * zc_cleanup_fd zevent file descriptor * * outputs: * zc_nvlist_dst next nvlist event * zc_cookie dropped events since last get - * zc_cleanup_fd cleanup-on-exit file descriptor */ static int zfs_ioc_events_next(zfs_cmd_t *zc)