[libvirt] [PATCH 3/3] storage: reduce number of stat calls
Eric Blake
eblake at redhat.com
Tue Nov 5 19:11:31 UTC 2013
We are calling fstat() at least twice per storage volume in
a directory storage pool; this is rather wasteful. Refactoring
this is also a step towards making code reusable for gluster,
where gluster can provide struct stat but cannot use fstat().
* src/storage/storage_backend.h
(virStorageBackendVolOpenCheckMode)
(virStorageBackendUpdateVolTargetInfoFD): Update signature.
* src/storage/storage_backend.c
(virStorageBackendVolOpenCheckMode): Pass stat results back.
(virStorageBackendUpdateVolTargetInfoFD): Use existing stats.
(virStorageBackendVolOpen, virStorageBackendUpdateVolTargetInfo):
Update callers.
* src/storage/storage_backend_fs.c (virStorageBackendProbeTarget):
Likewise.
* src/storage/storage_backend_scsi.c
(virStorageBackendSCSIUpdateVolTargetInfo): Likewise.
* src/storage/storage_backend_mpath.c
(virStorageBackendMpathUpdateVolTargetInfo): Likewise.
Signed-off-by: Eric Blake <eblake at redhat.com>
---
src/storage/storage_backend.c | 62 +++++++++++++++++--------------------
src/storage/storage_backend.h | 10 ++++--
src/storage/storage_backend_fs.c | 5 +--
src/storage/storage_backend_mpath.c | 7 +++--
src/storage/storage_backend_scsi.c | 7 +++--
5 files changed, 49 insertions(+), 42 deletions(-)
diff --git a/src/storage/storage_backend.c b/src/storage/storage_backend.c
index aa2ed28..4b1b00d 100644
--- a/src/storage/storage_backend.c
+++ b/src/storage/storage_backend.c
@@ -1152,30 +1152,30 @@ virStorageBackendForType(int type)
* volume is a dangling symbolic link.
*/
int
-virStorageBackendVolOpenCheckMode(const char *path, unsigned int flags)
+virStorageBackendVolOpenCheckMode(const char *path, struct stat *sb,
+ unsigned int flags)
{
int fd, mode = 0;
- struct stat sb;
char *base = last_component(path);
- if (lstat(path, &sb) < 0) {
+ if (lstat(path, sb) < 0) {
virReportSystemError(errno,
_("cannot stat file '%s'"),
path);
return -1;
}
- if (S_ISFIFO(sb.st_mode)) {
+ if (S_ISFIFO(sb->st_mode)) {
VIR_WARN("ignoring FIFO '%s'", path);
return -2;
- } else if (S_ISSOCK(sb.st_mode)) {
+ } else if (S_ISSOCK(sb->st_mode)) {
VIR_WARN("ignoring socket '%s'", path);
return -2;
}
if ((fd = open(path, O_RDONLY|O_NONBLOCK|O_NOCTTY)) < 0) {
if ((errno == ENOENT || errno == ELOOP) &&
- S_ISLNK(sb.st_mode)) {
+ S_ISLNK(sb->st_mode)) {
VIR_WARN("ignoring dangling symlink '%s'", path);
return -2;
}
@@ -1186,7 +1186,7 @@ virStorageBackendVolOpenCheckMode(const char *path, unsigned int flags)
return -1;
}
- if (fstat(fd, &sb) < 0) {
+ if (fstat(fd, sb) < 0) {
virReportSystemError(errno,
_("cannot stat file '%s'"),
path);
@@ -1194,13 +1194,13 @@ virStorageBackendVolOpenCheckMode(const char *path, unsigned int flags)
return -1;
}
- if (S_ISREG(sb.st_mode))
+ if (S_ISREG(sb->st_mode))
mode = VIR_STORAGE_VOL_OPEN_REG;
- else if (S_ISCHR(sb.st_mode))
+ else if (S_ISCHR(sb->st_mode))
mode = VIR_STORAGE_VOL_OPEN_CHAR;
- else if (S_ISBLK(sb.st_mode))
+ else if (S_ISBLK(sb->st_mode))
mode = VIR_STORAGE_VOL_OPEN_BLOCK;
- else if (S_ISDIR(sb.st_mode)) {
+ else if (S_ISDIR(sb->st_mode)) {
mode = VIR_STORAGE_VOL_OPEN_DIR;
if (STREQ(base, ".") ||
@@ -1229,7 +1229,8 @@ virStorageBackendVolOpenCheckMode(const char *path, unsigned int flags)
int virStorageBackendVolOpen(const char *path)
{
- return virStorageBackendVolOpenCheckMode(path,
+ struct stat sb;
+ return virStorageBackendVolOpenCheckMode(path, &sb,
VIR_STORAGE_VOL_OPEN_DEFAULT);
}
@@ -1240,14 +1241,16 @@ virStorageBackendUpdateVolTargetInfo(virStorageVolTargetPtr target,
unsigned int openflags)
{
int ret, fd;
+ struct stat sb;
- if ((ret = virStorageBackendVolOpenCheckMode(target->path,
+ if ((ret = virStorageBackendVolOpenCheckMode(target->path, &sb,
openflags)) < 0)
return ret;
fd = ret;
ret = virStorageBackendUpdateVolTargetInfoFD(target,
fd,
+ &sb,
allocation,
capacity);
@@ -1298,35 +1301,28 @@ int virStorageBackendUpdateVolInfo(virStorageVolDefPtr vol,
int
virStorageBackendUpdateVolTargetInfoFD(virStorageVolTargetPtr target,
int fd,
+ struct stat *sb,
unsigned long long *allocation,
unsigned long long *capacity)
{
- struct stat sb;
#if WITH_SELINUX
security_context_t filecon = NULL;
#endif
- if (fstat(fd, &sb) < 0) {
- virReportSystemError(errno,
- _("cannot stat file '%s'"),
- target->path);
- return -1;
- }
-
if (allocation) {
- if (S_ISREG(sb.st_mode)) {
+ if (S_ISREG(sb->st_mode)) {
#ifndef WIN32
- *allocation = (unsigned long long)sb.st_blocks *
+ *allocation = (unsigned long long)sb->st_blocks *
(unsigned long long)DEV_BSIZE;
#else
- *allocation = sb.st_size;
+ *allocation = sb->st_size;
#endif
/* Regular files may be sparse, so logical size (capacity) is not same
* as actual allocation above
*/
if (capacity)
- *capacity = sb.st_size;
- } else if (S_ISDIR(sb.st_mode)) {
+ *capacity = sb->st_size;
+ } else if (S_ISDIR(sb->st_mode)) {
*allocation = 0;
if (capacity)
*capacity = 0;
@@ -1351,16 +1347,16 @@ virStorageBackendUpdateVolTargetInfoFD(virStorageVolTargetPtr target,
}
}
- target->perms.mode = sb.st_mode & S_IRWXUGO;
- target->perms.uid = sb.st_uid;
- target->perms.gid = sb.st_gid;
+ target->perms.mode = sb->st_mode & S_IRWXUGO;
+ target->perms.uid = sb->st_uid;
+ target->perms.gid = sb->st_gid;
if (!target->timestamps && VIR_ALLOC(target->timestamps) < 0)
return -1;
- target->timestamps->atime = get_stat_atime(&sb);
- target->timestamps->btime = get_stat_birthtime(&sb);
- target->timestamps->ctime = get_stat_ctime(&sb);
- target->timestamps->mtime = get_stat_mtime(&sb);
+ target->timestamps->atime = get_stat_atime(sb);
+ target->timestamps->btime = get_stat_birthtime(sb);
+ target->timestamps->ctime = get_stat_ctime(sb);
+ target->timestamps->mtime = get_stat_mtime(sb);
VIR_FREE(target->perms.label);
diff --git a/src/storage/storage_backend.h b/src/storage/storage_backend.h
index 3dc9c64..d8d3097 100644
--- a/src/storage/storage_backend.h
+++ b/src/storage/storage_backend.h
@@ -24,6 +24,8 @@
#ifndef __VIR_STORAGE_BACKEND_H__
# define __VIR_STORAGE_BACKEND_H__
+# include <sys/stat.h>
+
# include "internal.h"
# include "storage_conf.h"
# include "vircommand.h"
@@ -108,9 +110,10 @@ enum {
VIR_STORAGE_VOL_OPEN_CHAR |\
VIR_STORAGE_VOL_OPEN_BLOCK)
-int virStorageBackendVolOpenCheckMode(const char *path, unsigned int flags)
-ATTRIBUTE_RETURN_CHECK
-ATTRIBUTE_NONNULL(1);
+int virStorageBackendVolOpenCheckMode(const char *path, struct stat *sb,
+ unsigned int flags)
+ ATTRIBUTE_RETURN_CHECK
+ ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2);
int virStorageBackendUpdateVolInfo(virStorageVolDefPtr vol,
int withCapacity);
@@ -124,6 +127,7 @@ int virStorageBackendUpdateVolTargetInfo(virStorageVolTargetPtr target,
unsigned int openflags);
int virStorageBackendUpdateVolTargetInfoFD(virStorageVolTargetPtr target,
int fd,
+ struct stat *sb,
unsigned long long *allocation,
unsigned long long *capacity);
int
diff --git a/src/storage/storage_backend_fs.c b/src/storage/storage_backend_fs.c
index 7ff950b..58fb7c1 100644
--- a/src/storage/storage_backend_fs.c
+++ b/src/storage/storage_backend_fs.c
@@ -70,18 +70,19 @@ virStorageBackendProbeTarget(virStorageVolTargetPtr target,
int fd = -1;
int ret = -1;
virStorageFileMetadata *meta = NULL;
+ struct stat sb;
*backingStore = NULL;
*backingStoreFormat = VIR_STORAGE_FILE_AUTO;
if (encryption)
*encryption = NULL;
- if ((ret = virStorageBackendVolOpenCheckMode(target->path,
+ if ((ret = virStorageBackendVolOpenCheckMode(target->path, &sb,
VIR_STORAGE_VOL_FS_REFRESH_FLAGS)) < 0)
goto error; /* Take care to propagate ret, it is not always -1 */
fd = ret;
- if ((ret = virStorageBackendUpdateVolTargetInfoFD(target, fd,
+ if ((ret = virStorageBackendUpdateVolTargetInfoFD(target, fd, &sb,
allocation,
capacity)) < 0) {
goto error;
diff --git a/src/storage/storage_backend_mpath.c b/src/storage/storage_backend_mpath.c
index 9a19484..1e65a8d 100644
--- a/src/storage/storage_backend_mpath.c
+++ b/src/storage/storage_backend_mpath.c
@@ -1,7 +1,7 @@
/*
* storage_backend_mpath.c: storage backend for multipath handling
*
- * Copyright (C) 2009-2011 Red Hat, Inc.
+ * Copyright (C) 2009-2011, 2013 Red Hat, Inc.
* Copyright (C) 2009-2008 Dave Allan
*
* This library is free software; you can redistribute it and/or
@@ -46,13 +46,16 @@ virStorageBackendMpathUpdateVolTargetInfo(virStorageVolTargetPtr target,
{
int ret = -1;
int fdret, fd = -1;
+ struct stat sb;
- if ((fdret = virStorageBackendVolOpen(target->path)) < 0)
+ if ((fdret = virStorageBackendVolOpenCheckMode(target->path, &sb,
+ VIR_STORAGE_VOL_OPEN_DEFAULT)) < 0)
goto out;
fd = fdret;
if (virStorageBackendUpdateVolTargetInfoFD(target,
fd,
+ &sb,
allocation,
capacity) < 0)
goto out;
diff --git a/src/storage/storage_backend_scsi.c b/src/storage/storage_backend_scsi.c
index 5769799..1426121 100644
--- a/src/storage/storage_backend_scsi.c
+++ b/src/storage/storage_backend_scsi.c
@@ -1,7 +1,7 @@
/*
* storage_backend_scsi.c: storage backend for SCSI handling
*
- * Copyright (C) 2007-2008 Red Hat, Inc.
+ * Copyright (C) 2007-2008, 2013 Red Hat, Inc.
* Copyright (C) 2007-2008 Daniel P. Berrange
*
* This library is free software; you can redistribute it and/or
@@ -138,13 +138,16 @@ virStorageBackendSCSIUpdateVolTargetInfo(virStorageVolTargetPtr target,
{
int fdret, fd = -1;
int ret = -1;
+ struct stat sb;
- if ((fdret = virStorageBackendVolOpen(target->path)) < 0)
+ if ((fdret = virStorageBackendVolOpenCheckMode(target->path, &sb,
+ VIR_STORAGE_VOL_OPEN_DEFAULT)) < 0)
goto cleanup;
fd = fdret;
if (virStorageBackendUpdateVolTargetInfoFD(target,
fd,
+ &sb,
allocation,
capacity) < 0)
goto cleanup;
--
1.8.3.1
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