Prevent unnecessary error from failing fsync(), if opened read only.
Performed 'grep "writeable = " *.h *.c' to make sure there were no odd
situations where fsync() might still be desired here. They're all straight-
forward. The only situation where writeable will be 0 is if btrfs_open_devices
is given flags without O_RDWR. There is no situation where a writeable volume
temporarily becomes unwriteable, or anything like that. Given that it's being
opened O_RDWR, there's no reason to attempt fsync().
utils.c
int btrfs_add_to_fsid() {
...
device->writeable = 1;
volumes.c
int btrfs_close_devices() {
...
while (!list_empty(&fs_devices->devices)) {
...
// just after the fsync() being patched
267: device->writeable = 0;
...
int btrfs_open_devices() {
...
list_for_each_entry(device, &fs_devices->devices, dev_list) {
...
if (flags & O_RDWR)
332: device->writeable = 1
kernel btrfs_close_devices() does not have a corresponding fsync() that I see.
Signed-off-by: James Harvey <jamespharvey20@xxxxxxxxx>
---
volumes.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/volumes.c b/volumes.c
index c6e34321..36d1bde6 100644
--- a/volumes.c
+++ b/volumes.c
@@ -254,7 +254,7 @@ again:
device = list_entry(fs_devices->devices.next,
struct btrfs_device, dev_list);
if (device->fd != -1) {
- if (fsync(device->fd) == -1) {
+ if (device->writeable && fsync(device->fd) == -1) {
warning("fsync on device %llu failed: %m",
device->devid);
ret = -errno;
--
2.17.0
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