Gitweb:
http://git.fedorahosted.org/git/?p=lvm2.git;a=commitdiff;h=6c0e44d5a2e82a...
Commit: 6c0e44d5a2e82aa160d48e83992e7ca342bc4bdf
Parent: 7c5feaed3be5c26f5782e4e891ba99862f1e968f
Author: Zdenek Kabelac <zkabelac(a)redhat.com>
AuthorDate: Fri Nov 25 10:01:37 2011 +0100
Committer: Zdenek Kabelac <zkabelac(a)redhat.com>
CommitterDate: Thu Dec 12 13:42:28 2013 +0100
dev-cache: skip double stat() call on each _insert
When the device is inserted in dev_name_confirmed() stat() is
called twice as _insert() has it's own stat() call.
Extend _insert() parameter with struct stat* - which could be used
if it has been just obtained. When NULL is passed code is
doing its own stat() call as before.
---
WHATS_NEW | 1 +
lib/device/dev-cache.c | 49 ++++++++++++++++++++++++++++++-----------------
2 files changed, 32 insertions(+), 18 deletions(-)
diff --git a/WHATS_NEW b/WHATS_NEW
index 704d0be..78657dd 100644
--- a/WHATS_NEW
+++ b/WHATS_NEW
@@ -1,5 +1,6 @@
Version 2.02.105 -
=====================================
+ Optimize double call of stat() for cached devices.
Enable support for thin provisioning for default configuration.
Improve process_each_lv_in_vg() tag processing.
Reodered and simplified logging code.
diff --git a/lib/device/dev-cache.c b/lib/device/dev-cache.c
index bbdde92..fabdcbb 100644
--- a/lib/device/dev-cache.c
+++ b/lib/device/dev-cache.c
@@ -50,7 +50,8 @@ static struct {
#define _free(x) dm_pool_free(_cache.mem, (x))
#define _strdup(x) dm_pool_strdup(_cache.mem, (x))
-static int _insert(const char *path, int rec, int check_with_udev_db);
+static int _insert(const char *path, const struct stat *info,
+ int rec, int check_with_udev_db);
/* Setup non-zero members of passed zeroed 'struct device' */
static void _dev_init(struct device *dev, int max_error_count)
@@ -442,7 +443,7 @@ static int _insert_dir(const char *dir)
return_0;
_collapse_slashes(path);
- r &= _insert(path, 1, 0);
+ r &= _insert(path, NULL, 1, 0);
dm_free(path);
free(dirent[n]);
@@ -528,14 +529,14 @@ static int _insert_udev_dir(struct udev *udev, const char *dir)
log_very_verbose("udev failed to return a device node for entry %s.",
entry_name);
else
- r &= _insert(node_name, 0, 0);
+ r &= _insert(node_name, NULL, 0, 0);
udev_list_entry_foreach(symlink_entry, udev_device_get_devlinks_list_entry(device)) {
if (!(symlink_name = udev_list_entry_get_name(symlink_entry)))
log_very_verbose("udev failed to return a symlink name for entry %s.",
entry_name);
else
- r &= _insert(symlink_name, 0, 0);
+ r &= _insert(symlink_name, NULL, 0, 0);
}
udev_device_unref(device);
@@ -589,28 +590,33 @@ static void _insert_dirs(struct dm_list *dirs)
#endif /* UDEV_SYNC_SUPPORT */
-static int _insert(const char *path, int rec, int check_with_udev_db)
+static int _insert(const char *path, const struct stat *info,
+ int rec, int check_with_udev_db)
{
- struct stat info;
+ struct stat tinfo;
+ int r = 0;
- if (stat(path, &info) < 0) {
- log_sys_very_verbose("stat", path);
- return 0;
+ if (!info) {
+ if (stat(path, &tinfo) < 0) {
+ log_sys_very_verbose("stat", path);
+ return 0;
+ }
+ info = &tinfo;
}
- if (check_with_udev_db && !_device_in_udev_db(info.st_rdev)) {
+ if (check_with_udev_db && !_device_in_udev_db(info->st_rdev)) {
log_very_verbose("%s: Not in udev db", path);
return 0;
}
- if (S_ISDIR(info.st_mode)) { /* add a directory */
+ if (S_ISDIR(info->st_mode)) { /* add a directory */
/* check it's not a symbolic link */
- if (lstat(path, &info) < 0) {
+ if (lstat(path, &tinfo) < 0) {
log_sys_very_verbose("lstat", path);
return 0;
}
- if (S_ISLNK(info.st_mode)) {
+ if (S_ISLNK(tinfo.st_mode)) {
log_debug_devs("%s: Symbolic link to directory", path);
return 1;
}
@@ -618,12 +624,12 @@ static int _insert(const char *path, int rec, int
check_with_udev_db)
if (rec && !_insert_dir(path))
return_0;
} else { /* add a device */
- if (!S_ISBLK(info.st_mode)) {
+ if (!S_ISBLK(info->st_mode)) {
log_debug_devs("%s: Not a block device", path);
return 1;
}
- if (!_insert_dev(path, info.st_rdev))
+ if (!_insert_dev(path, info->st_rdev))
return_0;
}
@@ -881,7 +887,7 @@ const char *dev_name_confirmed(struct device *dev, int quiet)
if (dm_list_size(&dev->aliases) > 1) {
dm_list_del(dev->aliases.n);
if (!r)
- _insert(name, 0, obtain_device_list_from_udev());
+ _insert(name, &buf, 0, obtain_device_list_from_udev());
continue;
}
@@ -903,13 +909,20 @@ struct device *dev_cache_get(const char *name, struct dev_filter
*f)
return d;
/* If the entry's wrong, remove it */
- if (d && (stat(name, &buf) || (buf.st_rdev != d->dev))) {
+ if (stat(name, &buf) < 0) {
+ if (d)
+ dm_hash_remove(_cache.names, name);
+ log_sys_very_verbose("stat", name);
+ return NULL;
+ }
+
+ if (d && (buf.st_rdev != d->dev)) {
dm_hash_remove(_cache.names, name);
d = NULL;
}
if (!d) {
- _insert(name, 0, obtain_device_list_from_udev());
+ _insert(name, &buf, 0, obtain_device_list_from_udev());
d = (struct device *) dm_hash_lookup(_cache.names, name);
if (!d) {
_full_scan(0);