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From 81f0a57bed6e03eeaa24443d16555c7f5d20ee1a Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Wed, 22 Apr 2015 13:08:19 +0200
Subject: [PATCH] btrfs-util: introduce btrfs_is_filesystem() and make use of
it where appropriate
Let's unify the code that checks whether an fd is on btrfs a bit.
(Also, rename btrfs_is_snapshot() to btrfs_is_subvol(), since that's
usually how this is referred to in our code)
(cherry picked from commit 21222ea5cdec65fa30a75bd5a78475459075b946)
Related: #1299714
---
src/shared/btrfs-util.c | 23 ++++++++++++++++-------
src/shared/btrfs-util.h | 3 ++-
src/shared/machine-image.c | 9 ++++-----
3 files changed, 22 insertions(+), 13 deletions(-)
diff --git a/src/shared/btrfs-util.c b/src/shared/btrfs-util.c
index b34ac8b15a..52a2143494 100644
--- a/src/shared/btrfs-util.c
+++ b/src/shared/btrfs-util.c
@@ -83,10 +83,22 @@ static int extract_subvolume_name(const char *path, const char **subvolume) {
return 0;
}
-int btrfs_is_snapshot(int fd) {
- struct stat st;
+int btrfs_is_filesystem(int fd) {
struct statfs sfs;
+ assert(fd >= 0);
+
+ if (fstatfs(fd, &sfs) < 0)
+ return -errno;
+
+ return F_TYPE_EQUAL(sfs.f_type, BTRFS_SUPER_MAGIC);
+}
+
+int btrfs_is_subvol(int fd) {
+ struct stat st;
+
+ assert(fd >= 0);
+
/* On btrfs subvolumes always have the inode 256 */
if (fstat(fd, &st) < 0)
@@ -95,10 +107,7 @@ int btrfs_is_snapshot(int fd) {
if (!S_ISDIR(st.st_mode) || st.st_ino != 256)
return 0;
- if (fstatfs(fd, &sfs) < 0)
- return -errno;
-
- return F_TYPE_EQUAL(sfs.f_type, BTRFS_SUPER_MAGIC);
+ return btrfs_is_filesystem(fd);
}
int btrfs_subvol_snapshot(const char *old_path, const char *new_path, bool read_only, bool fallback_copy) {
@@ -115,7 +124,7 @@ int btrfs_subvol_snapshot(const char *old_path, const char *new_path, bool read_
if (old_fd < 0)
return -errno;
- r = btrfs_is_snapshot(old_fd);
+ r = btrfs_is_subvol(old_fd);
if (r < 0)
return r;
if (r == 0) {
diff --git a/src/shared/btrfs-util.h b/src/shared/btrfs-util.h
index 1b9c142e5c..1315def87e 100644
--- a/src/shared/btrfs-util.h
+++ b/src/shared/btrfs-util.h
@@ -43,7 +43,8 @@ typedef struct BtrfsQuotaInfo {
uint64_t exclusive_max;
} BtrfsQuotaInfo;
-int btrfs_is_snapshot(int fd);
+int btrfs_is_filesystem(int fd);
+int btrfs_is_subvol(int fd);
int btrfs_subvol_make(const char *path);
int btrfs_subvol_make_label(const char *path);
diff --git a/src/shared/machine-image.c b/src/shared/machine-image.c
index c02ee814c4..2566229282 100644
--- a/src/shared/machine-image.c
+++ b/src/shared/machine-image.c
@@ -136,12 +136,11 @@ static int image_make(
/* btrfs subvolumes have inode 256 */
if (st.st_ino == 256) {
- struct statfs sfs;
- if (fstatfs(fd, &sfs) < 0)
- return -errno;
-
- if (F_TYPE_EQUAL(sfs.f_type, BTRFS_SUPER_MAGIC)) {
+ r = btrfs_is_filesystem(fd);
+ if (r < 0)
+ return r;
+ if (r) {
BtrfsSubvolInfo info;
BtrfsQuotaInfo quota;