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path: make the check for unsupported name_to_handle_at symmetric

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If child supports, but the parent does not, or when the child does
not support, but the parent does, assume the child is a mount point.

Only if neither supports use the fallback.
This commit is contained in:
Zbigniew Jędrzejewski-Szmek 2014-12-17 21:05:58 -05:00
parent b890bf6a81
commit 6feeeab0bc
1 changed files with 20 additions and 15 deletions
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35
src/shared/path-util.c
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@ -462,6 +462,7 @@ int path_is_mount_point(const char *t, bool allow_symlink) {
_cleanup_free_ char *parent = NULL;
struct stat a, b;
int r;
bool nosupp = false;
/* We are not actually interested in the file handles, but
* name_to_handle_at() also passes us the mount ID, hence use
@ -476,12 +477,11 @@ int path_is_mount_point(const char *t, bool allow_symlink) {
/* This kernel or file system does not support
* name_to_handle_at(), hence fallback to the
* traditional stat() logic */
goto fallback;
if (errno == ENOENT)
nosupp = true;
else if (errno == ENOENT)
return 0;
return -errno;
else
return -errno;
}
r = path_get_parent(t, &parent);
@ -490,17 +490,22 @@ int path_is_mount_point(const char *t, bool allow_symlink) {
h.handle.handle_bytes = MAX_HANDLE_SZ;
r = name_to_handle_at(AT_FDCWD, parent, &h.handle, &mount_id_parent, AT_SYMLINK_FOLLOW);
if (r < 0) {
/* The parent can't do name_to_handle_at() but the
* directory we are interested in can? If so, it must
* be a mount point */
if (r < 0)
if (errno == EOPNOTSUPP)
return 1;
return -errno;
}
return mount_id != mount_id_parent;
if (nosupp)
/* Neither parent nor child do name_to_handle_at()?
We have no choice but to fall back. */
goto fallback;
else
/* The parent can't do name_to_handle_at() but
* the directory we are interested in can?
* Or the other way around?
* If so, it must be a mount point. */
return 1;
else
return -errno;
else
return mount_id != mount_id_parent;
fallback:
if (allow_symlink)