When FS pool's source is already mounted on the target location instead of just simply marking the pool as active, thus starting it we fail with an error stating that the source is indeed already mounted on the target. Signed-off-by: Erik Skultety <eskultet(a)redhat.com&gt; --- src/storage/storage_backend_fs.c | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-) diff --git a/src/storage/storage_backend_fs.c b/src/storage/storage_backend_fs.c index 54bcc57..fe4705b 100644 --- a/src/storage/storage_backend_fs.c +++ b/src/storage/storage_backend_fs.c @@ -358,14 +358,13 @@ virStorageBackendFileSystemMount(virStoragePoolObjPtr pool) if (virStorageBackendFileSystemIsValid(pool) < 0) return -1; + if ((rc = virStorageBackendFileSystemIsMounted(pool)) < 0) + return -1; + /* Short-circuit if already mounted */ - if ((rc = virStorageBackendFileSystemIsMounted(pool)) != 0) { - if (rc == 1) { - virReportError(VIR_ERR_OPERATION_INVALID, - _("Target '%s' is already mounted"), - pool->def->target.path); - } - return -1; + if (rc == 1) { + VIR_INFO("Target '%s' is already mounted", pool->def->target.path); + return 0; } if (!(src = virStorageBackendFileSystemGetPoolSource(pool))) -- 2.10.2

So rather than comparing 2 paths (strings) as they are, which can very easily lead to unnecessary errors (e.g. in storage driver) that the paths are not the same when in fact they'd be e.g. just symlinks to the same location, we should put our best effort into resolving any symlinks and canonicalizing the path and only then compare the 2 paths. Signed-off-by: Erik Skultety <eskultet(a)redhat.com&gt; --- src/libvirt_private.syms | 1 + src/util/virfile.c | 45 +++++++++++++++++++++++++++++++++++++++++++++ src/util/virfile.h | 2 ++ 3 files changed, 48 insertions(+) diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms index 8e994c7..06f3737 100644 --- a/src/libvirt_private.syms +++ b/src/libvirt_private.syms @@ -1575,6 +1575,7 @@ virFileActivateDirOverride; virFileBindMountDevice; virFileBuildPath; virFileClose; +virFileComparePaths; virFileCopyACLs; virFileDeleteTree; virFileDirectFdFlag; diff --git a/src/util/virfile.c b/src/util/virfile.c index bf8099e..b261632 100644 --- a/src/util/virfile.c +++ b/src/util/virfile.c @@ -3737,3 +3737,48 @@ virFileCopyACLs(const char *src, virFileFreeACLs(&acl); return ret; } + +/* + * virFileComparePaths: + * @p1: source path 1 + * @p2: source path 2 + * + * Compares two paths for equality. To do so, it first canonicalizes both paths + * to resolve all symlinks and discard relative path components. If symlinks + * resolution or path canonicalization fails, plain string equality of @p1 + * and @p2 is performed. + * + * Returns 0 if the paths are equal, 1 if they're not or -1 in case of an + * error. + */ +int +virFileComparePaths(const char *p1, const char *p2) +{ + int ret = -1; + char *res1, *res2; + + res1 = res2 = NULL; + + /* Assume p1 and p2 are symlinks, so try to resolve and canonicalize them. + * Canonicalization fails for example on file systems names like 'proc' or + * 'sysfs', since they're no real paths so fallback to plain string + * comparison. + */ + ignore_value(virFileResolveLink(p1, &res1)); + if (!res1 && VIR_STRDUP(res1, p1) < 0) + goto cleanup; + + ignore_value(virFileResolveLink(p2, &res2)); + if (!res2 && VIR_STRDUP(res2, p2) < 0) + goto cleanup; + + if (STREQ_NULLABLE(res1, res2)) + ret = 0; + else + ret = 1; + + cleanup: + VIR_FREE(res1); + VIR_FREE(res2); + return ret; +} diff --git a/src/util/virfile.h b/src/util/virfile.h index 0343acd..5822b29 100644 --- a/src/util/virfile.h +++ b/src/util/virfile.h @@ -331,4 +331,6 @@ void virFileFreeACLs(void **acl); int virFileCopyACLs(const char *src, const char *dst); + +int virFileComparePaths(const char *p1, const char *p2); #endif /* __VIR_FILE_H */ -- 2.10.2

Well, having the substring "Resolved" in the name IMHO implies that the paths to be compared should already by resolved in which case the whole point of the function doesn't make sense, since you'd simply use STREQ. So for this reason I prefer just ComparePaths. I really wanted it to be called *Equal but sort of implies the return type boolean which is inapplicable because of the VIR_STRDUP :(. Well, that was my initial thought, the code would look cleaner, I also liked it more, but then I thought, most of our compare functions use strcmp for comparison at some point, so I wanted to follow the convention of returning 0 when equal. However, it wasn't until you suggested it that I grep'ed our code and found virReadCompareWWN that works exactly the way I'd favour. So, yeah, I should have gone with my initial gut feeling, I'll adjust this appropriately, thanks. Erik

On 02/07/2017 09:16 AM, Erik Skultety wrote: With changes to previous to return 1 on match, then this gets adjusted too... ACK - I think you can alter this appropriately John