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libbe(3): move altroot augmentation bits around a little bit

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We could perhaps have a method that does this given a dataset, but it's yet
clear that we'll always want to bypass the altroot when we grab the
mountpoint. For now, we'll refactor things a bit so we grab the altroot
length when libbe is initialized and have a common method that does the
necessary augmentation (replace with / if it's the root, return a pointer to
later in the string if not).

This will be used in some upcoming work to make be_mount work properly for
deep BEs.

MFC after:	1 week
This commit is contained in:
kevans 2019-01-09 22:31:10 +00:00
parent 48665600ce
commit 044685cd18
3 changed files with 38 additions and 14 deletions
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21
lib/libbe/be.c
View File

@ -90,6 +90,7 @@ be_locate_rootfs(libbe_handle_t *lbh)
libbe_handle_t *
libbe_init(const char *root)
{
char altroot[MAXPATHLEN];
libbe_handle_t *lbh;
char *poolname, *pos;
int pnamelen;
@ -140,6 +141,11 @@ libbe_init(const char *root)
sizeof(lbh->bootfs), NULL, true) != 0)
goto err;
if (zpool_get_prop(lbh->active_phandle, ZPOOL_PROP_ALTROOT,
altroot, sizeof(altroot), NULL, true) == 0 &&
strcmp(altroot, "-") != 0)
lbh->altroot_len = strlen(altroot);
return (lbh);
err:
if (lbh != NULL) {
@ -314,7 +320,6 @@ be_create(libbe_handle_t *lbh, const char *name)
return (set_error(lbh, err));
}
static int
be_deep_clone_prop(int prop, void *cb)
{
@ -345,12 +350,9 @@ be_deep_clone_prop(int prop, void *cb)
/* Augment mountpoint with altroot, if needed */
val = pval;
if (prop == ZFS_PROP_MOUNTPOINT && *dccb->altroot != '\0') {
if (pval[strlen(dccb->altroot)] == '\0')
strlcpy(pval, "/", sizeof(pval));
else
val = pval + strlen(dccb->altroot);
}
if (prop == ZFS_PROP_MOUNTPOINT)
val = be_mountpoint_augmented(dccb->lbh, val);
nvlist_add_string(dccb->props, zfs_prop_to_name(prop), val);
return (ZPROP_CONT);
@ -392,12 +394,9 @@ be_deep_clone(zfs_handle_t *ds, void *data)
nvlist_alloc(&props, NV_UNIQUE_NAME, KM_SLEEP);
nvlist_add_string(props, "canmount", "noauto");
dccb.lbh = isdc->lbh;
dccb.zhp = ds;
dccb.props = props;
if (zpool_get_prop(isdc->lbh->active_phandle, ZPOOL_PROP_ALTROOT,
dccb.altroot, sizeof(dccb.altroot), NULL, true) != 0 ||
strcmp(dccb.altroot, "-") == 0)
*dccb.altroot = '\0';
if (zprop_iter(be_deep_clone_prop, &dccb, B_FALSE, B_FALSE,
ZFS_TYPE_FILESYSTEM) == ZPROP_INVAL)
return (-1);

22
lib/libbe/be_access.c
View File

@ -195,3 +195,25 @@ be_unmount(libbe_handle_t *lbh, char *bootenv, int flags)
return (BE_ERR_SUCCESS);
}
/*
* This function will blow away the input buffer as needed if we're discovered
* to be looking at a root-mount. If the mountpoint is naturally beyond the
* root, however, the buffer may be left intact and a pointer to the section
* past altroot will be returned instead for the caller's perusal.
*/
char *
be_mountpoint_augmented(libbe_handle_t *lbh, char *mountpoint)
{
if (lbh->altroot_len == 0)
return (mountpoint);
if (mountpoint == NULL || *mountpoint == '\0')
return (mountpoint);
if (mountpoint[lbh->altroot_len] == '\0') {
*(mountpoint + 1) = '\0';
return (mountpoint);
} else
return (mountpoint + lbh->altroot_len);
}

9
lib/libbe/be_impl.h
View File

@ -36,11 +36,12 @@
#include "be.h"
struct libbe_handle {
libzfs_handle_t *lzh;
zpool_handle_t *active_phandle;
char root[BE_MAXPATHLEN];
char rootfs[BE_MAXPATHLEN];
char bootfs[BE_MAXPATHLEN];
size_t altroot_len;
zpool_handle_t *active_phandle;
libzfs_handle_t *lzh;
be_error_t error;
bool print_on_err;
};
@ -53,9 +54,9 @@ struct libbe_deep_clone {
};
struct libbe_dccb {
libbe_handle_t *lbh;
zfs_handle_t *zhp;
nvlist_t *props;
char altroot[MAXPATHLEN];
};
typedef struct prop_data {
@ -67,6 +68,8 @@ typedef struct prop_data {
int prop_list_builder_cb(zfs_handle_t *, void *);
int be_proplist_update(prop_data_t *);
char *be_mountpoint_augmented(libbe_handle_t *lbh, char *mountpoint);
/* Clobbers any previous errors */
int set_error(libbe_handle_t *, be_error_t);