On Thu, Mar 7, 2013 at 12:10 PM, Swâmi Petaramesh <swami@xxxxxxxxxxxxxx> wrote:
> Le 07/03/2013 19:06, Jérôme Poulin a écrit :
>> mkfs.btrfs tries to lookup loop devices by their filenames and fails
>> if any loop device file is missing.
>
> Hmm.... Why would mkfs.btrfs want to lookup anything else but the device
> we're trying to format, to check if it's mounted or not ?
>
At Sabayon, we pretty-much hacked our way around this with a
"make-it-go" kind of patch.
Otherwise, our installation would break with btrfs on our
Live-[CD/DVD/USB] media.
I know we should have taken the time to put together a proper
solution, but I could never figure out the reasoning for needing to
scan every device either.
--- btrfs-progs-0.19.orig/utils.c
+++ btrfs-progs-0.19/utils.c
@@ -708,6 +708,21 @@ int is_same_blk_file(const char* a, cons
return 0;
}
+/* Checks if a file exists and is a block or regular file*/
+int is_existing_blk_or_reg_file(const char* filename)
+{
+ struct stat st_buf;
+
+ if(stat(filename, &st_buf) < 0) {
+ if(errno == ENOENT)
+ return 0;
+ else
+ return -errno;
+ }
+
+ return (S_ISBLK(st_buf.st_mode) || S_ISREG(st_buf.st_mode));
+}
+
/* checks if a and b are identical or device
* files associated with the same block device or
* if one file is a loop device that uses the other
@@ -727,7 +742,10 @@ int is_same_loop_file(const char* a, con
} else if(ret) {
if((ret = resolve_loop_device(a, res_a, sizeof(res_a))) < 0)
return ret;
-
+ /* if the resolved path is not available, there is nothing
+ we can do */
+ if((ret = is_existing_blk_or_reg_file(res_a)) == 0)
+ return ret;
final_a = res_a;
} else {
final_a = a;
@@ -739,6 +757,10 @@ int is_same_loop_file(const char* a, con
} else if(ret) {
if((ret = resolve_loop_device(b, res_b, sizeof(res_b))) < 0)
return ret;
+ /* if the resolved path is not available, there is nothing
+ we can do */
+ if((ret = is_existing_blk_or_reg_file(res_b)) == 0)
+ return ret;
final_b = res_b;
} else {
@@ -748,21 +770,6 @@ int is_same_loop_file(const char* a, con
return is_same_blk_file(final_a, final_b);
}
-/* Checks if a file exists and is a block or regular file*/
-int is_existing_blk_or_reg_file(const char* filename)
-{
- struct stat st_buf;
-
- if(stat(filename, &st_buf) < 0) {
- if(errno == ENOENT)
- return 0;
- else
- return -errno;
- }
-
- return (S_ISBLK(st_buf.st_mode) || S_ISREG(st_buf.st_mode));
-}
-
/* Checks if a file is used (directly or indirectly via a loop device)
* by a device in fs_devices
*/
--
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