lib/label/label.c | 61 +++++++++++++++++++++++++++++++++++++++++++++++++++++++

 1 file changed, 61 insertions(+)

diff --git a/lib/label/label.c b/lib/label/label.c

index 72be5ec..09bbb92 100644

--- a/lib/label/label.c

+++ b/lib/label/label.c

@@ -29,6 +29,7 @@

 #include <fcntl.h>

 #include <unistd.h>

 #include <sys/types.h>

+#include <sys/resource.h>

 /* FIXME Allow for larger labels?  Restricted to single sector currently */

@@ -867,6 +868,57 @@ static void _free_hints(struct dm_list *hints)

 }

 /*

+ * We don't know how many of num_devs will be PVs that we need to

+ * keep open, but if it's greater than the soft limit, then we'll

+ * need the soft limit raised, so do that before starting.

+ *

+ * If opens approach the raised soft/hard limit while scanning, then

+ * we could also attempt to raise the soft/hard limits during the scan.

+ */

+

+#define BASE_FD_COUNT 32 /* Number of open files we want apart from devs */

+

+static void _prepare_open_file_limit(struct cmd_context *cmd, unsigned int num_devs)

+{

+	struct rlimit old, new;

+	unsigned int want = num_devs + BASE_FD_COUNT;

+	int rv;

+

+	rv = prlimit(0, RLIMIT_NOFILE, NULL, &old;;

+	if (rv < 0) {

+		log_debug("Checking fd limit for num_devs %u failed %d", num_devs, errno);

+		return;

+	}

+

+	log_debug("Checking fd limit for num_devs %u want %u soft %lld hard %lld",

+		  num_devs, want, (long long)old.rlim_cur, (long long)old.rlim_max);

+

+	/* Current soft limit is enough */

+	if (old.rlim_cur > want)

+		return;

+

+	/* Soft limit already raised to max */

+	if (old.rlim_cur == old.rlim_max)

+		return;

+

+	/* Raise soft limit up to hard/max limit */

+	new.rlim_cur = old.rlim_max;

+	new.rlim_max = old.rlim_max;

+

+	log_debug("Setting fd limit for num_devs %u soft %lld hard %lld",

+		  num_devs, (long long)new.rlim_cur, (long long)new.rlim_max);

+

+	rv = prlimit(0, RLIMIT_NOFILE, &new, &old;;

+	if (rv < 0) {

+		if (errno == EPERM)

+			log_warn("WARNING: permission error setting open file limit for scanning %u devices.", num_devs);

+		else

+			log_warn("WARNING: cannot set open file limit for scanning %u devices.", num_devs);

+		return;

+	}

+}

+

+/*

  * Scan devices on the system to discover which are LVM devices.

  * Info about the LVM devices (PVs) is saved in lvmcache in a

  * basic/summary form (info/vginfo structs).  The vg_read phase

@@ -984,6 +1036,15 @@ int label_scan(struct cmd_context *cmd)

 	log_debug("Will scan %d devices skip %d", dm_list_size(&scan_devs), dm_list_size(&all_devs));

 	/*

+	 * If the total number of devices exceeds the soft open file

+	 * limit, then increase the soft limit to the hard/max limit

+	 * in case the number of PVs in scan_devs (it's only the PVs

+	 * which we want to keep open) is higher than the current

+	 * soft limit.

+	 */

+	_prepare_open_file_limit(cmd, dm_list_size(&scan_devs));

+

+	/*

 	 * Do the main scan.

 	 */

 	_scan_list(cmd, cmd->filter, &scan_devs, NULL);