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btrfs: use a structure to pass arguments to backref walking functions

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The public backref walking functions have quite a lot of arguments that
are passed down the call stack to find_parent_nodes(), the core function
of the backref walking code.

The next patches in series will need to add even arguments to these
functions that should be passed not only to find_parent_nodes(), but also
to other functions used by the later (directly or even lower in the call
stack).

So create a structure to hold all these arguments and state used by the
main backref walking function, find_parent_nodes(), and use it as the
argument for the public backref walking functions iterate_extent_inodes(),
btrfs_find_all_leafs() and btrfs_find_all_roots().

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Filipe Manana 2022-11-01 16:15:47 +00:00 committed by David Sterba
parent 6ce6ba5344
commit a2c8d27e5e
7 changed files with 328 additions and 227 deletions
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339
fs/btrfs/backref.c
View File

@ -444,12 +444,12 @@ static int is_shared_data_backref(struct preftrees *preftrees, u64 bytenr)
return 0;
}
static int add_all_parents(struct btrfs_root *root, struct btrfs_path *path,
static int add_all_parents(struct btrfs_backref_walk_ctx *ctx,
struct btrfs_root *root, struct btrfs_path *path,
struct ulist *parents,
struct preftrees *preftrees, struct prelim_ref *ref,
int level, u64 time_seq, u64 extent_item_pos)
int level)
{
const bool ignore_offset = (extent_item_pos == BTRFS_IGNORE_EXTENT_OFFSET);
int ret = 0;
int slot;
struct extent_buffer *eb;
@ -484,10 +484,10 @@ static int add_all_parents(struct btrfs_root *root, struct btrfs_path *path,
if (path->slots[0] >= btrfs_header_nritems(eb) ||
is_shared_data_backref(preftrees, eb->start) ||
ref->root_id != btrfs_header_owner(eb)) {
if (time_seq == BTRFS_SEQ_LAST)
if (ctx->time_seq == BTRFS_SEQ_LAST)
ret = btrfs_next_leaf(root, path);
else
ret = btrfs_next_old_leaf(root, path, time_seq);
ret = btrfs_next_old_leaf(root, path, ctx->time_seq);
}
while (!ret && count < ref->count) {
@ -508,10 +508,10 @@ static int add_all_parents(struct btrfs_root *root, struct btrfs_path *path,
if (slot == 0 &&
(is_shared_data_backref(preftrees, eb->start) ||
ref->root_id != btrfs_header_owner(eb))) {
if (time_seq == BTRFS_SEQ_LAST)
if (ctx->time_seq == BTRFS_SEQ_LAST)
ret = btrfs_next_leaf(root, path);
else
ret = btrfs_next_old_leaf(root, path, time_seq);
ret = btrfs_next_old_leaf(root, path, ctx->time_seq);
continue;
}
fi = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item);
@ -525,9 +525,9 @@ static int add_all_parents(struct btrfs_root *root, struct btrfs_path *path,
count++;
else
goto next;
if (!ignore_offset) {
if (!ctx->ignore_extent_item_pos) {
ret = check_extent_in_eb(&key, eb, fi,
extent_item_pos, &eie);
ctx->extent_item_pos, &eie);
if (ret < 0)
break;
}
@ -537,7 +537,7 @@ static int add_all_parents(struct btrfs_root *root, struct btrfs_path *path,
eie, (void **)&old, GFP_NOFS);
if (ret < 0)
break;
if (!ret && !ignore_offset) {
if (!ret && !ctx->ignore_extent_item_pos) {
while (old->next)
old = old->next;
old->next = eie;
@ -545,10 +545,10 @@ static int add_all_parents(struct btrfs_root *root, struct btrfs_path *path,
eie = NULL;
}
next:
if (time_seq == BTRFS_SEQ_LAST)
if (ctx->time_seq == BTRFS_SEQ_LAST)
ret = btrfs_next_item(root, path);
else
ret = btrfs_next_old_item(root, path, time_seq);
ret = btrfs_next_old_item(root, path, ctx->time_seq);
}
if (ret > 0)
@ -562,11 +562,10 @@ next:
* resolve an indirect backref in the form (root_id, key, level)
* to a logical address
*/
static int resolve_indirect_ref(struct btrfs_fs_info *fs_info,
struct btrfs_path *path, u64 time_seq,
static int resolve_indirect_ref(struct btrfs_backref_walk_ctx *ctx,
struct btrfs_path *path,
struct preftrees *preftrees,
struct prelim_ref *ref, struct ulist *parents,
u64 extent_item_pos)
struct prelim_ref *ref, struct ulist *parents)
{
struct btrfs_root *root;
struct extent_buffer *eb;
@ -584,9 +583,9 @@ static int resolve_indirect_ref(struct btrfs_fs_info *fs_info,
* here.
*/
if (path->search_commit_root)
root = btrfs_get_fs_root_commit_root(fs_info, path, ref->root_id);
root = btrfs_get_fs_root_commit_root(ctx->fs_info, path, ref->root_id);
else
root = btrfs_get_fs_root(fs_info, ref->root_id, false);
root = btrfs_get_fs_root(ctx->fs_info, ref->root_id, false);
if (IS_ERR(root)) {
ret = PTR_ERR(root);
goto out_free;
@ -598,17 +597,17 @@ static int resolve_indirect_ref(struct btrfs_fs_info *fs_info,
goto out;
}
if (btrfs_is_testing(fs_info)) {
if (btrfs_is_testing(ctx->fs_info)) {
ret = -ENOENT;
goto out;
}
if (path->search_commit_root)
root_level = btrfs_header_level(root->commit_root);
else if (time_seq == BTRFS_SEQ_LAST)
else if (ctx->time_seq == BTRFS_SEQ_LAST)
root_level = btrfs_header_level(root->node);
else
root_level = btrfs_old_root_level(root, time_seq);
root_level = btrfs_old_root_level(root, ctx->time_seq);
if (root_level + 1 == level)
goto out;
@ -636,12 +635,12 @@ static int resolve_indirect_ref(struct btrfs_fs_info *fs_info,
search_key.offset >= LLONG_MAX)
search_key.offset = 0;
path->lowest_level = level;
if (time_seq == BTRFS_SEQ_LAST)
if (ctx->time_seq == BTRFS_SEQ_LAST)
ret = btrfs_search_slot(NULL, root, &search_key, path, 0, 0);
else
ret = btrfs_search_old_slot(root, &search_key, path, time_seq);
ret = btrfs_search_old_slot(root, &search_key, path, ctx->time_seq);
btrfs_debug(fs_info,
btrfs_debug(ctx->fs_info,
"search slot in root %llu (level %d, ref count %d) returned %d for key (%llu %u %llu)",
ref->root_id, level, ref->count, ret,
ref->key_for_search.objectid, ref->key_for_search.type,
@ -659,8 +658,7 @@ static int resolve_indirect_ref(struct btrfs_fs_info *fs_info,
eb = path->nodes[level];
}
ret = add_all_parents(root, path, parents, preftrees, ref, level,
time_seq, extent_item_pos);
ret = add_all_parents(ctx, root, path, parents, preftrees, ref, level);
out:
btrfs_put_root(root);
out_free:
@ -705,10 +703,9 @@ static void free_leaf_list(struct ulist *ulist)
* rbtree as they are encountered. The new backrefs are subsequently
* resolved as above.
*/
static int resolve_indirect_refs(struct btrfs_fs_info *fs_info,
struct btrfs_path *path, u64 time_seq,
static int resolve_indirect_refs(struct btrfs_backref_walk_ctx *ctx,
struct btrfs_path *path,
struct preftrees *preftrees,
u64 extent_item_pos,
struct share_check *sc)
{
int err;
@ -751,14 +748,13 @@ static int resolve_indirect_refs(struct btrfs_fs_info *fs_info,
ret = BACKREF_FOUND_SHARED;
goto out;
}
err = resolve_indirect_ref(fs_info, path, time_seq, preftrees,
ref, parents, extent_item_pos);
err = resolve_indirect_ref(ctx, path, preftrees, ref, parents);
/*
* we can only tolerate ENOENT,otherwise,we should catch error
* and return directly.
*/
if (err == -ENOENT) {
prelim_ref_insert(fs_info, &preftrees->direct, ref,
prelim_ref_insert(ctx->fs_info, &preftrees->direct, ref,
NULL);
continue;
} else if (err) {
@ -787,7 +783,7 @@ static int resolve_indirect_refs(struct btrfs_fs_info *fs_info,
memcpy(new_ref, ref, sizeof(*ref));
new_ref->parent = node->val;
new_ref->inode_list = unode_aux_to_inode_list(node);
prelim_ref_insert(fs_info, &preftrees->direct,
prelim_ref_insert(ctx->fs_info, &preftrees->direct,
new_ref, NULL);
}
@ -795,7 +791,7 @@ static int resolve_indirect_refs(struct btrfs_fs_info *fs_info,
* Now it's a direct ref, put it in the direct tree. We must
* do this last because the ref could be merged/freed here.
*/
prelim_ref_insert(fs_info, &preftrees->direct, ref, NULL);
prelim_ref_insert(ctx->fs_info, &preftrees->direct, ref, NULL);
ulist_reinit(parents);
cond_resched();
@ -1325,32 +1321,18 @@ static void store_backref_shared_cache(struct btrfs_backref_share_check_ctx *ctx
* indirect refs to their parent bytenr.
* When roots are found, they're added to the roots list
*
* If time_seq is set to BTRFS_SEQ_LAST, it will not search delayed_refs, and
* behave much like trans == NULL case, the difference only lies in it will not
* commit root.
* The special case is for qgroup to search roots in commit_transaction().
*
* @sc - if !NULL, then immediately return BACKREF_FOUND_SHARED when a
* @ctx: Backref walking context object, must be not NULL.
* @sc: If !NULL, then immediately return BACKREF_FOUND_SHARED when a
* shared extent is detected.
*
* Otherwise this returns 0 for success and <0 for an error.
*
* @extent_item_pos is meaningful only if we are dealing with a data extent.
* If its value is not BTRFS_IGNORE_EXTENT_OFFSET, then only collect references
* from file extent items that refer to a section of the data extent that
* contains @extent_item_pos. If its value is BTRFS_IGNORE_EXTENT_OFFSET then
* collect references for every file extent item that points to the data extent.
*
* FIXME some caching might speed things up
*/
static int find_parent_nodes(struct btrfs_trans_handle *trans,
struct btrfs_fs_info *fs_info, u64 bytenr,
u64 time_seq, struct ulist *refs,
struct ulist *roots, u64 extent_item_pos,
static int find_parent_nodes(struct btrfs_backref_walk_ctx *ctx,
struct share_check *sc)
{
const bool ignore_offset = (extent_item_pos == BTRFS_IGNORE_EXTENT_OFFSET);
struct btrfs_root *root = btrfs_extent_root(fs_info, bytenr);
struct btrfs_root *root = btrfs_extent_root(ctx->fs_info, ctx->bytenr);
struct btrfs_key key;
struct btrfs_path *path;
struct btrfs_delayed_ref_root *delayed_refs = NULL;
@ -1368,11 +1350,11 @@ static int find_parent_nodes(struct btrfs_trans_handle *trans,
/* Roots ulist is not needed when using a sharedness check context. */
if (sc)
ASSERT(roots == NULL);
ASSERT(ctx->roots == NULL);
key.objectid = bytenr;
key.objectid = ctx->bytenr;
key.offset = (u64)-1;
if (btrfs_fs_incompat(fs_info, SKINNY_METADATA))
if (btrfs_fs_incompat(ctx->fs_info, SKINNY_METADATA))
key.type = BTRFS_METADATA_ITEM_KEY;
else
key.type = BTRFS_EXTENT_ITEM_KEY;
@ -1380,12 +1362,12 @@ static int find_parent_nodes(struct btrfs_trans_handle *trans,
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
if (!trans) {
if (!ctx->trans) {
path->search_commit_root = 1;
path->skip_locking = 1;
}
if (time_seq == BTRFS_SEQ_LAST)
if (ctx->time_seq == BTRFS_SEQ_LAST)
path->skip_locking = 1;
again:
@ -1401,17 +1383,17 @@ again:
goto out;
}
if (trans && likely(trans->type != __TRANS_DUMMY) &&
time_seq != BTRFS_SEQ_LAST) {
if (ctx->trans && likely(ctx->trans->type != __TRANS_DUMMY) &&
ctx->time_seq != BTRFS_SEQ_LAST) {
/*
* We have a specific time_seq we care about and trans which
* means we have the path lock, we need to grab the ref head and
* lock it so we have a consistent view of the refs at the given
* time.
*/
delayed_refs = &trans->transaction->delayed_refs;
delayed_refs = &ctx->trans->transaction->delayed_refs;
spin_lock(&delayed_refs->lock);
head = btrfs_find_delayed_ref_head(delayed_refs, bytenr);
head = btrfs_find_delayed_ref_head(delayed_refs, ctx->bytenr);
if (head) {
if (!mutex_trylock(&head->mutex)) {
refcount_inc(&head->refs);
@ -1429,7 +1411,7 @@ again:
goto again;
}
spin_unlock(&delayed_refs->lock);
ret = add_delayed_refs(fs_info, head, time_seq,
ret = add_delayed_refs(ctx->fs_info, head, ctx->time_seq,
&preftrees, sc);
mutex_unlock(&head->mutex);
if (ret)
@ -1447,14 +1429,14 @@ again:
leaf = path->nodes[0];
slot = path->slots[0];
btrfs_item_key_to_cpu(leaf, &key, slot);
if (key.objectid == bytenr &&
if (key.objectid == ctx->bytenr &&
(key.type == BTRFS_EXTENT_ITEM_KEY ||
key.type == BTRFS_METADATA_ITEM_KEY)) {
ret = add_inline_refs(fs_info, path, bytenr,
ret = add_inline_refs(ctx->fs_info, path, ctx->bytenr,
&info_level, &preftrees, sc);
if (ret)
goto out;
ret = add_keyed_refs(root, path, bytenr, info_level,
ret = add_keyed_refs(root, path, ctx->bytenr, info_level,
&preftrees, sc);
if (ret)
goto out;
@ -1483,7 +1465,7 @@ again:
* extent item pointing to the data extent) is shared, that is, if any
* of the extent buffers in the path is referenced by other trees.
*/
if (sc && bytenr == sc->data_bytenr) {
if (sc && ctx->bytenr == sc->data_bytenr) {
/*
* If our data extent is from a generation more recent than the
* last generation used to snapshot the root, then we know that
@ -1530,14 +1512,13 @@ again:
btrfs_release_path(path);
ret = add_missing_keys(fs_info, &preftrees, path->skip_locking == 0);
ret = add_missing_keys(ctx->fs_info, &preftrees, path->skip_locking == 0);
if (ret)
goto out;
WARN_ON(!RB_EMPTY_ROOT(&preftrees.indirect_missing_keys.root.rb_root));
ret = resolve_indirect_refs(fs_info, path, time_seq, &preftrees,
extent_item_pos, sc);
ret = resolve_indirect_refs(ctx, path, &preftrees, sc);
if (ret)
goto out;
@ -1564,17 +1545,18 @@ again:
* e.g. different offsets would not be merged,
* and would retain their original ref->count < 0.
*/
if (roots && ref->count && ref->root_id && ref->parent == 0) {
if (ctx->roots && ref->count && ref->root_id && ref->parent == 0) {
/* no parent == root of tree */
ret = ulist_add(roots, ref->root_id, 0, GFP_NOFS);
ret = ulist_add(ctx->roots, ref->root_id, 0, GFP_NOFS);
if (ret < 0)
goto out;
}
if (ref->count && ref->parent) {
if (!ignore_offset && !ref->inode_list && ref->level == 0) {
if (!ctx->ignore_extent_item_pos && !ref->inode_list &&
ref->level == 0) {
struct extent_buffer *eb;
eb = read_tree_block(fs_info, ref->parent, 0,
eb = read_tree_block(ctx->fs_info, ref->parent, 0,
0, ref->level, NULL);
if (IS_ERR(eb)) {
ret = PTR_ERR(eb);
@ -1588,8 +1570,8 @@ again:
if (!path->skip_locking)
btrfs_tree_read_lock(eb);
ret = find_extent_in_eb(eb, bytenr,
extent_item_pos, &eie);
ret = find_extent_in_eb(eb, ctx->bytenr,
ctx->extent_item_pos, &eie);
if (!path->skip_locking)
btrfs_tree_read_unlock(eb);
free_extent_buffer(eb);
@ -1603,12 +1585,12 @@ again:
*/
eie = NULL;
}
ret = ulist_add_merge_ptr(refs, ref->parent,
ret = ulist_add_merge_ptr(ctx->refs, ref->parent,
ref->inode_list,
(void **)&eie, GFP_NOFS);
if (ret < 0)
goto out;
if (!ret && !ignore_offset) {
if (!ret && !ctx->ignore_extent_item_pos) {
/*
* We've recorded that parent, so we must extend
* its inode list here.
@ -1652,28 +1634,29 @@ out:
}
/*
* Finds all leafs with a reference to the specified combination of bytenr and
* offset. key_list_head will point to a list of corresponding keys (caller must
* free each list element). The leafs will be stored in the leafs ulist, which
* must be freed with ulist_free.
* Finds all leaves with a reference to the specified combination of
* @ctx->bytenr and @ctx->extent_item_pos. The bytenr of the found leaves are
* added to the ulist at @ctx->refs, and that ulist is allocated by this
* function. The caller should free the ulist with free_leaf_list() if
* @ctx->ignore_extent_item_pos is false, otherwise a fimple ulist_free() is
* enough.
*
* returns 0 on success, <0 on error
* Returns 0 on success and < 0 on error. On error @ctx->refs is not allocated.
*/
int btrfs_find_all_leafs(struct btrfs_trans_handle *trans,
struct btrfs_fs_info *fs_info, u64 bytenr,
u64 time_seq, struct ulist **leafs,
u64 extent_item_pos)
int btrfs_find_all_leafs(struct btrfs_backref_walk_ctx *ctx)
{
int ret;
*leafs = ulist_alloc(GFP_NOFS);
if (!*leafs)
ASSERT(ctx->refs == NULL);
ctx->refs = ulist_alloc(GFP_NOFS);
if (!ctx->refs)
return -ENOMEM;
ret = find_parent_nodes(trans, fs_info, bytenr, time_seq,
*leafs, NULL, extent_item_pos, NULL);
ret = find_parent_nodes(ctx, NULL);
if (ret < 0 && ret != -ENOENT) {
free_leaf_list(*leafs);
free_leaf_list(ctx->refs);
ctx->refs = NULL;
return ret;
}
@ -1681,7 +1664,7 @@ int btrfs_find_all_leafs(struct btrfs_trans_handle *trans,
}
/*
* walk all backrefs for a given extent to find all roots that reference this
* Walk all backrefs for a given extent to find all roots that reference this
* extent. Walking a backref means finding all extents that reference this
* extent and in turn walk the backrefs of those, too. Naturally this is a
* recursive process, but here it is implemented in an iterative fashion: We
@ -1689,62 +1672,74 @@ int btrfs_find_all_leafs(struct btrfs_trans_handle *trans,
* list. In turn, we find all referencing extents for those, further appending
* to the list. The way we iterate the list allows adding more elements after
* the current while iterating. The process stops when we reach the end of the
* list. Found roots are added to the roots list.
* list.
*
* returns 0 on success, < 0 on error.
* Found roots are added to @ctx->roots, which is allocated by this function and
* @ctx->roots should be NULL when calling this function. This function also
* requires @ctx->refs to be NULL, as it uses it for allocating a ulist to do
* temporary work, and frees it before returning.
*
* Returns 0 on success, < 0 on error. On error @ctx->roots is always NULL.
*/
static int btrfs_find_all_roots_safe(struct btrfs_trans_handle *trans,
struct btrfs_fs_info *fs_info, u64 bytenr,
u64 time_seq, struct ulist **roots)
static int btrfs_find_all_roots_safe(struct btrfs_backref_walk_ctx *ctx)
{
struct ulist *tmp;
struct ulist_node *node = NULL;
const u64 orig_bytenr = ctx->bytenr;
const bool orig_ignore_extent_item_pos = ctx->ignore_extent_item_pos;
struct ulist_iterator uiter;
int ret;
int ret = 0;
tmp = ulist_alloc(GFP_NOFS);
if (!tmp)
ASSERT(ctx->refs == NULL);
ASSERT(ctx->roots == NULL);
ctx->refs = ulist_alloc(GFP_NOFS);
if (!ctx->refs)
return -ENOMEM;
*roots = ulist_alloc(GFP_NOFS);
if (!*roots) {
ulist_free(tmp);
ctx->roots = ulist_alloc(GFP_NOFS);
if (!ctx->roots) {
ulist_free(ctx->refs);
ctx->refs = NULL;
return -ENOMEM;
}
ctx->ignore_extent_item_pos = true;
ULIST_ITER_INIT(&uiter);
while (1) {
ret = find_parent_nodes(trans, fs_info, bytenr, time_seq,
tmp, *roots, BTRFS_IGNORE_EXTENT_OFFSET,
NULL);
struct ulist_node *node;
ret = find_parent_nodes(ctx, NULL);
if (ret < 0 && ret != -ENOENT) {
ulist_free(tmp);
ulist_free(*roots);
*roots = NULL;
return ret;
ulist_free(ctx->roots);
ctx->roots = NULL;
break;
}
node = ulist_next(tmp, &uiter);
ret = 0;
node = ulist_next(ctx->refs, &uiter);
if (!node)
break;
bytenr = node->val;
ctx->bytenr = node->val;
cond_resched();
}
ulist_free(tmp);
return 0;
ulist_free(ctx->refs);
ctx->refs = NULL;
ctx->bytenr = orig_bytenr;
ctx->ignore_extent_item_pos = orig_ignore_extent_item_pos;
return ret;
}
int btrfs_find_all_roots(struct btrfs_trans_handle *trans,
struct btrfs_fs_info *fs_info, u64 bytenr,
u64 time_seq, struct ulist **roots,
int btrfs_find_all_roots(struct btrfs_backref_walk_ctx *ctx,
bool skip_commit_root_sem)
{
int ret;
if (!trans && !skip_commit_root_sem)
down_read(&fs_info->commit_root_sem);
ret = btrfs_find_all_roots_safe(trans, fs_info, bytenr, time_seq, roots);
if (!trans && !skip_commit_root_sem)
up_read(&fs_info->commit_root_sem);
if (!ctx->trans && !skip_commit_root_sem)
down_read(&ctx->fs_info->commit_root_sem);
ret = btrfs_find_all_roots_safe(ctx);
if (!ctx->trans && !skip_commit_root_sem)
up_read(&ctx->fs_info->commit_root_sem);
return ret;
}
@ -1794,6 +1789,7 @@ int btrfs_is_data_extent_shared(struct btrfs_inode *inode, u64 bytenr,
u64 extent_gen,
struct btrfs_backref_share_check_ctx *ctx)
{
struct btrfs_backref_walk_ctx walk_ctx = { 0 };
struct btrfs_root *root = inode->root;
struct btrfs_fs_info *fs_info = root->fs_info;
struct btrfs_trans_handle *trans;
@ -1830,8 +1826,14 @@ int btrfs_is_data_extent_shared(struct btrfs_inode *inode, u64 bytenr,
down_read(&fs_info->commit_root_sem);
} else {
btrfs_get_tree_mod_seq(fs_info, &elem);
walk_ctx.time_seq = elem.seq;
}
walk_ctx.ignore_extent_item_pos = true;
walk_ctx.trans = trans;
walk_ctx.fs_info = fs_info;
walk_ctx.refs = &ctx->refs;
/* -1 means we are in the bytenr of the data extent. */
level = -1;
ULIST_ITER_INIT(&uiter);
@ -1840,8 +1842,8 @@ int btrfs_is_data_extent_shared(struct btrfs_inode *inode, u64 bytenr,
bool is_shared;
bool cached;
ret = find_parent_nodes(trans, fs_info, bytenr, elem.seq, &ctx->refs,
NULL, BTRFS_IGNORE_EXTENT_OFFSET, &shared);
walk_ctx.bytenr = bytenr;
ret = find_parent_nodes(&walk_ctx, &shared);
if (ret == BACKREF_FOUND_SHARED ||
ret == BACKREF_FOUND_NOT_SHARED) {
/* If shared must return 1, otherwise return 0. */
@ -2279,73 +2281,81 @@ static int iterate_leaf_refs(struct btrfs_fs_info *fs_info,
* the given parameters.
* when the iterator function returns a non-zero value, iteration stops.
*/
int iterate_extent_inodes(struct btrfs_fs_info *fs_info,
u64 extent_item_objectid, u64 extent_item_pos,
int search_commit_root,
iterate_extent_inodes_t *iterate, void *ctx)
int iterate_extent_inodes(struct btrfs_backref_walk_ctx *ctx,
bool search_commit_root,
iterate_extent_inodes_t *iterate, void *user_ctx)
{
int ret;
struct btrfs_trans_handle *trans = NULL;
struct ulist *refs = NULL;
struct ulist *roots = NULL;
struct ulist_node *ref_node = NULL;
struct ulist_node *root_node = NULL;
struct ulist *refs;
struct ulist_node *ref_node;
struct btrfs_seq_list seq_elem = BTRFS_SEQ_LIST_INIT(seq_elem);
struct ulist_iterator ref_uiter;
struct ulist_iterator root_uiter;
btrfs_debug(fs_info, "resolving all inodes for extent %llu",
extent_item_objectid);
btrfs_debug(ctx->fs_info, "resolving all inodes for extent %llu",
ctx->bytenr);
ASSERT(ctx->trans == NULL);
if (!search_commit_root) {
trans = btrfs_attach_transaction(fs_info->tree_root);
struct btrfs_trans_handle *trans;
trans = btrfs_attach_transaction(ctx->fs_info->tree_root);
if (IS_ERR(trans)) {
if (PTR_ERR(trans) != -ENOENT &&
PTR_ERR(trans) != -EROFS)
return PTR_ERR(trans);
trans = NULL;
}
ctx->trans = trans;
}
if (trans)
btrfs_get_tree_mod_seq(fs_info, &seq_elem);
else
down_read(&fs_info->commit_root_sem);
if (ctx->trans) {
btrfs_get_tree_mod_seq(ctx->fs_info, &seq_elem);
ctx->time_seq = seq_elem.seq;
} else {
down_read(&ctx->fs_info->commit_root_sem);
}
ret = btrfs_find_all_leafs(trans, fs_info, extent_item_objectid,
seq_elem.seq, &refs, extent_item_pos);
ret = btrfs_find_all_leafs(ctx);
if (ret)
goto out;
refs = ctx->refs;
ctx->refs = NULL;
ULIST_ITER_INIT(&ref_uiter);
while (!ret && (ref_node = ulist_next(refs, &ref_uiter))) {
ret = btrfs_find_all_roots_safe(trans, fs_info, ref_node->val,
seq_elem.seq, &roots);
struct ulist_node *root_node;
struct ulist_iterator root_uiter;
ctx->bytenr = ref_node->val;
ret = btrfs_find_all_roots_safe(ctx);
if (ret)
break;
ULIST_ITER_INIT(&root_uiter);
while (!ret && (root_node = ulist_next(roots, &root_uiter))) {
btrfs_debug(fs_info,
while (!ret && (root_node = ulist_next(ctx->roots, &root_uiter))) {
btrfs_debug(ctx->fs_info,
"root %llu references leaf %llu, data list %#llx",
root_node->val, ref_node->val,
ref_node->aux);
ret = iterate_leaf_refs(fs_info,
ret = iterate_leaf_refs(ctx->fs_info,
(struct extent_inode_elem *)
(uintptr_t)ref_node->aux,
root_node->val,
extent_item_objectid,
iterate, ctx);
root_node->val, ctx->bytenr,
iterate, user_ctx);
}
ulist_free(roots);
ulist_free(ctx->roots);
ctx->roots = NULL;
}
free_leaf_list(refs);
out:
if (trans) {
btrfs_put_tree_mod_seq(fs_info, &seq_elem);
btrfs_end_transaction(trans);
if (ctx->trans) {
btrfs_put_tree_mod_seq(ctx->fs_info, &seq_elem);
btrfs_end_transaction(ctx->trans);
ctx->trans = NULL;
} else {
up_read(&fs_info->commit_root_sem);
up_read(&ctx->fs_info->commit_root_sem);
}
return ret;
@ -2375,8 +2385,8 @@ int iterate_inodes_from_logical(u64 logical, struct btrfs_fs_info *fs_info,
struct btrfs_path *path,
void *ctx, bool ignore_offset)
{
struct btrfs_backref_walk_ctx walk_ctx = { 0 };
int ret;
u64 extent_item_pos;
u64 flags = 0;
struct btrfs_key found_key;
int search_commit_root = path->search_commit_root;
@ -2388,16 +2398,15 @@ int iterate_inodes_from_logical(u64 logical, struct btrfs_fs_info *fs_info,
if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)
return -EINVAL;
walk_ctx.bytenr = found_key.objectid;
if (ignore_offset)
extent_item_pos = BTRFS_IGNORE_EXTENT_OFFSET;
walk_ctx.ignore_extent_item_pos = true;
else
extent_item_pos = logical - found_key.objectid;
walk_ctx.extent_item_pos = logical - found_key.objectid;
walk_ctx.fs_info = fs_info;
ret = iterate_extent_inodes(fs_info, found_key.objectid,
extent_item_pos, search_commit_root,
return iterate_extent_inodes(&walk_ctx, search_commit_root,
build_ino_list, ctx);
return ret;
}
static int inode_to_path(u64 inum, u32 name_len, unsigned long name_off,

76
fs/btrfs/backref.h
View File

@ -13,11 +13,63 @@
#include "extent_io.h"
/*
* Pass to backref walking functions to tell them to include references from
* all file extent items that point to the target data extent, regardless if
* they refer to the whole extent or just sections of it (bookend extents).
* Context and arguments for backref walking functions. Some of the fields are
* to be filled by the caller of such functions while other are filled by the
* functions themselves, as described below.
*/
#define BTRFS_IGNORE_EXTENT_OFFSET ((u64)-1)
struct btrfs_backref_walk_ctx {
/*
* The address of the extent for which we are doing backref walking.
* Can be either a data extent or a metadata extent.
*
* Must always be set by the top level caller.
*/
u64 bytenr;
/*
* Offset relative to the target extent. This is only used for data
* extents, and it's meaningful because we can have file extent items
* that point only to a section of a data extent ("bookend" extents),
* and we want to filter out any that don't point to a section of the
* data extent containing the given offset.
*
* Must always be set by the top level caller.
*/
u64 extent_item_pos;
/*
* If true and bytenr corresponds to a data extent, then references from
* all file extent items that point to the data extent are considered,
* @extent_item_pos is ignored.
*/
bool ignore_extent_item_pos;
/* A valid transaction handle or NULL. */
struct btrfs_trans_handle *trans;
/*
* The file system's info object, can not be NULL.
*
* Must always be set by the top level caller.
*/
struct btrfs_fs_info *fs_info;
/*
* Time sequence acquired from btrfs_get_tree_mod_seq(), in case the
* caller joined the tree mod log to get a consistent view of b+trees
* while we do backref walking, or BTRFS_SEQ_LAST.
* When using BTRFS_SEQ_LAST, delayed refs are not checked and it uses
* commit roots when searching b+trees - this is a special case for
* qgroups used during a transaction commit.
*/
u64 time_seq;
/*
* Used to collect the bytenr of metadata extents that point to the
* target extent.
*/
struct ulist *refs;
/*
* List used to collect the IDs of the roots from which the target
* extent is accessible. Can be NULL in case the caller does not care
* about collecting root IDs.
*/
struct ulist *roots;
};
struct inode_fs_paths {
struct btrfs_path *btrfs_path;
@ -96,10 +148,9 @@ int tree_backref_for_extent(unsigned long *ptr, struct extent_buffer *eb,
struct btrfs_key *key, struct btrfs_extent_item *ei,
u32 item_size, u64 *out_root, u8 *out_level);
int iterate_extent_inodes(struct btrfs_fs_info *fs_info,
u64 extent_item_objectid,
u64 extent_offset, int search_commit_root,
iterate_extent_inodes_t *iterate, void *ctx);
int iterate_extent_inodes(struct btrfs_backref_walk_ctx *ctx,
bool search_commit_root,
iterate_extent_inodes_t *iterate, void *user_ctx);
int iterate_inodes_from_logical(u64 logical, struct btrfs_fs_info *fs_info,
struct btrfs_path *path, void *ctx,
@ -107,13 +158,8 @@ int iterate_inodes_from_logical(u64 logical, struct btrfs_fs_info *fs_info,
int paths_from_inode(u64 inum, struct inode_fs_paths *ipath);
int btrfs_find_all_leafs(struct btrfs_trans_handle *trans,
struct btrfs_fs_info *fs_info, u64 bytenr,
u64 time_seq, struct ulist **leafs,
u64 extent_item_pos);
int btrfs_find_all_roots(struct btrfs_trans_handle *trans,
struct btrfs_fs_info *fs_info, u64 bytenr,
u64 time_seq, struct ulist **roots,
int btrfs_find_all_leafs(struct btrfs_backref_walk_ctx *ctx);
int btrfs_find_all_roots(struct btrfs_backref_walk_ctx *ctx,
bool skip_commit_root_sem);
char *btrfs_ref_to_path(struct btrfs_root *fs_root, struct btrfs_path *path,
u32 name_len, unsigned long name_off,

38
fs/btrfs/qgroup.c
View File

@ -1794,8 +1794,7 @@ int btrfs_qgroup_trace_extent_nolock(struct btrfs_fs_info *fs_info,
int btrfs_qgroup_trace_extent_post(struct btrfs_trans_handle *trans,
struct btrfs_qgroup_extent_record *qrecord)
{
struct ulist *old_root;
u64 bytenr = qrecord->bytenr;
struct btrfs_backref_walk_ctx ctx = { 0 };
int ret;
/*
@ -1822,8 +1821,10 @@ int btrfs_qgroup_trace_extent_post(struct btrfs_trans_handle *trans,
if (trans->fs_info->qgroup_flags & BTRFS_QGROUP_RUNTIME_FLAG_NO_ACCOUNTING)
return 0;
ret = btrfs_find_all_roots(NULL, trans->fs_info, bytenr, 0, &old_root,
true);
ctx.bytenr = qrecord->bytenr;
ctx.fs_info = trans->fs_info;
ret = btrfs_find_all_roots(&ctx, true);
if (ret < 0) {
qgroup_mark_inconsistent(trans->fs_info);
btrfs_warn(trans->fs_info,
@ -1839,7 +1840,7 @@ int btrfs_qgroup_trace_extent_post(struct btrfs_trans_handle *trans,
*
* So modifying qrecord->old_roots is safe here
*/
qrecord->old_roots = old_root;
qrecord->old_roots = ctx.roots;
return 0;
}
@ -2750,17 +2751,22 @@ int btrfs_qgroup_account_extents(struct btrfs_trans_handle *trans)
if (!ret && !(fs_info->qgroup_flags &
BTRFS_QGROUP_RUNTIME_FLAG_NO_ACCOUNTING)) {
struct btrfs_backref_walk_ctx ctx = { 0 };
ctx.bytenr = record->bytenr;
ctx.fs_info = fs_info;
/*
* Old roots should be searched when inserting qgroup
* extent record
*/
if (WARN_ON(!record->old_roots)) {
/* Search commit root to find old_roots */
ret = btrfs_find_all_roots(NULL, fs_info,
record->bytenr, 0,
&record->old_roots, false);
ret = btrfs_find_all_roots(&ctx, false);
if (ret < 0)
goto cleanup;
record->old_roots = ctx.roots;
ctx.roots = NULL;
}
/* Free the reserved data space */
@ -2773,10 +2779,11 @@ int btrfs_qgroup_account_extents(struct btrfs_trans_handle *trans)
* which doesn't lock tree or delayed_refs and search
* current root. It's safe inside commit_transaction().
*/
ret = btrfs_find_all_roots(trans, fs_info,
record->bytenr, BTRFS_SEQ_LAST, &new_roots, false);
ctx.trans = trans;
ret = btrfs_find_all_roots(&ctx, false);
if (ret < 0)
goto cleanup;
new_roots = ctx.roots;
if (qgroup_to_skip) {
ulist_del(new_roots, qgroup_to_skip, 0);
ulist_del(record->old_roots, qgroup_to_skip,
@ -3242,7 +3249,6 @@ static int qgroup_rescan_leaf(struct btrfs_trans_handle *trans,
struct btrfs_root *extent_root;
struct btrfs_key found;
struct extent_buffer *scratch_leaf = NULL;
struct ulist *roots = NULL;
u64 num_bytes;
bool done;
int slot;
@ -3292,6 +3298,8 @@ static int qgroup_rescan_leaf(struct btrfs_trans_handle *trans,
mutex_unlock(&fs_info->qgroup_rescan_lock);
for (; slot < btrfs_header_nritems(scratch_leaf); ++slot) {
struct btrfs_backref_walk_ctx ctx = { 0 };
btrfs_item_key_to_cpu(scratch_leaf, &found, slot);
if (found.type != BTRFS_EXTENT_ITEM_KEY &&
found.type != BTRFS_METADATA_ITEM_KEY)
@ -3301,13 +3309,15 @@ static int qgroup_rescan_leaf(struct btrfs_trans_handle *trans,
else
num_bytes = found.offset;
ret = btrfs_find_all_roots(NULL, fs_info, found.objectid, 0,
&roots, false);
ctx.bytenr = found.objectid;
ctx.fs_info = fs_info;
ret = btrfs_find_all_roots(&ctx, false);
if (ret < 0)
goto out;
/* For rescan, just pass old_roots as NULL */
ret = btrfs_qgroup_account_extent(trans, found.objectid,
num_bytes, NULL, roots);
num_bytes, NULL, ctx.roots);
if (ret < 0)
goto out;
}

19
fs/btrfs/relocation.c
View File

@ -3408,24 +3408,27 @@ int add_data_references(struct reloc_control *rc,
struct btrfs_path *path,
struct rb_root *blocks)
{
struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
struct ulist *leaves = NULL;
struct btrfs_backref_walk_ctx ctx = { 0 };
struct ulist_iterator leaf_uiter;
struct ulist_node *ref_node = NULL;
const u32 blocksize = fs_info->nodesize;
const u32 blocksize = rc->extent_root->fs_info->nodesize;
int ret = 0;
btrfs_release_path(path);
ret = btrfs_find_all_leafs(NULL, fs_info, extent_key->objectid,
0, &leaves, BTRFS_IGNORE_EXTENT_OFFSET);
ctx.bytenr = extent_key->objectid;
ctx.ignore_extent_item_pos = true;
ctx.fs_info = rc->extent_root->fs_info;
ret = btrfs_find_all_leafs(&ctx);
if (ret < 0)
return ret;
ULIST_ITER_INIT(&leaf_uiter);
while ((ref_node = ulist_next(leaves, &leaf_uiter))) {
while ((ref_node = ulist_next(ctx.refs, &leaf_uiter))) {
struct extent_buffer *eb;
eb = read_tree_block(fs_info, ref_node->val, 0, 0, 0, NULL);
eb = read_tree_block(ctx.fs_info, ref_node->val, 0, 0, 0, NULL);
if (IS_ERR(eb)) {
ret = PTR_ERR(eb);
break;
@ -3441,7 +3444,7 @@ int add_data_references(struct reloc_control *rc,
}
if (ret < 0)
free_block_list(blocks);
ulist_free(leaves);
ulist_free(ctx.refs);
return ret;
}

14
fs/btrfs/scrub.c
View File

@ -909,7 +909,6 @@ static void scrub_print_warning(const char *errstr, struct scrub_block *sblock)
struct btrfs_extent_item *ei;
struct scrub_warning swarn;
unsigned long ptr = 0;
u64 extent_item_pos;
u64 flags = 0;
u64 ref_root;
u32 item_size;
@ -941,7 +940,6 @@ static void scrub_print_warning(const char *errstr, struct scrub_block *sblock)
if (ret < 0)
goto out;
extent_item_pos = swarn.logical - found_key.objectid;
swarn.extent_item_size = found_key.offset;
eb = path->nodes[0];
@ -964,12 +962,18 @@ static void scrub_print_warning(const char *errstr, struct scrub_block *sblock)
} while (ret != 1);
btrfs_release_path(path);
} else {
struct btrfs_backref_walk_ctx ctx = { 0 };
btrfs_release_path(path);
ctx.bytenr = found_key.objectid;
ctx.extent_item_pos = swarn.logical - found_key.objectid;
ctx.fs_info = fs_info;
swarn.path = path;
swarn.dev = dev;
iterate_extent_inodes(fs_info, found_key.objectid,
extent_item_pos, 1,
scrub_print_warning_inode, &swarn);
iterate_extent_inodes(&ctx, true, scrub_print_warning_inode, &swarn);
}
out:

13
fs/btrfs/send.c
View File

@ -1356,12 +1356,12 @@ static int find_extent_clone(struct send_ctx *sctx,
u64 logical;
u64 disk_byte;
u64 num_bytes;
u64 extent_item_pos;
u64 extent_refs;
u64 flags = 0;
struct btrfs_file_extent_item *fi;
struct extent_buffer *eb = path->nodes[0];
struct backref_ctx backref_ctx = { 0 };
struct btrfs_backref_walk_ctx backref_walk_ctx = { 0 };
struct clone_root *cur_clone_root;
struct btrfs_key found_key;
struct btrfs_path *tmp_path;
@ -1461,14 +1461,13 @@ static int find_extent_clone(struct send_ctx *sctx,
/*
* Now collect all backrefs.
*/
backref_walk_ctx.bytenr = found_key.objectid;
if (compressed == BTRFS_COMPRESS_NONE)
extent_item_pos = logical - found_key.objectid;
else
extent_item_pos = 0;
ret = iterate_extent_inodes(fs_info, found_key.objectid,
extent_item_pos, 1, __iterate_backrefs,
&backref_ctx);
backref_walk_ctx.extent_item_pos = logical - found_key.objectid;
backref_walk_ctx.fs_info = fs_info;
ret = iterate_extent_inodes(&backref_walk_ctx, true, __iterate_backrefs,
&backref_ctx);
if (ret < 0)
goto out;

50
fs/btrfs/tests/qgroup-tests.c
View File

@ -205,6 +205,7 @@ static int remove_extent_ref(struct btrfs_root *root, u64 bytenr,
static int test_no_shared_qgroup(struct btrfs_root *root,
u32 sectorsize, u32 nodesize)
{
struct btrfs_backref_walk_ctx ctx = { 0 };
struct btrfs_trans_handle trans;
struct btrfs_fs_info *fs_info = root->fs_info;
struct ulist *old_roots = NULL;
@ -220,16 +221,22 @@ static int test_no_shared_qgroup(struct btrfs_root *root,
return ret;
}
ctx.bytenr = nodesize;
ctx.trans = &trans;
ctx.fs_info = fs_info;
/*
* Since the test trans doesn't have the complicated delayed refs,
* we can only call btrfs_qgroup_account_extent() directly to test
* quota.
*/
ret = btrfs_find_all_roots(&trans, fs_info, nodesize, 0, &old_roots, false);
ret = btrfs_find_all_roots(&ctx, false);
if (ret) {
test_err("couldn't find old roots: %d", ret);
return ret;
}
old_roots = ctx.roots;
ctx.roots = NULL;
ret = insert_normal_tree_ref(root, nodesize, nodesize, 0,
BTRFS_FS_TREE_OBJECTID);
@ -238,12 +245,14 @@ static int test_no_shared_qgroup(struct btrfs_root *root,
return ret;
}
ret = btrfs_find_all_roots(&trans, fs_info, nodesize, 0, &new_roots, false);
ret = btrfs_find_all_roots(&ctx, false);
if (ret) {
ulist_free(old_roots);
test_err("couldn't find old roots: %d", ret);
return ret;
}
new_roots = ctx.roots;
ctx.roots = NULL;
ret = btrfs_qgroup_account_extent(&trans, nodesize, nodesize, old_roots,
new_roots);
@ -262,11 +271,13 @@ static int test_no_shared_qgroup(struct btrfs_root *root,
return -EINVAL;
}
ret = btrfs_find_all_roots(&trans, fs_info, nodesize, 0, &old_roots, false);
ret = btrfs_find_all_roots(&ctx, false);
if (ret) {
test_err("couldn't find old roots: %d", ret);
return ret;
}
old_roots = ctx.roots;
ctx.roots = NULL;
ret = remove_extent_item(root, nodesize, nodesize);
if (ret) {
@ -274,12 +285,14 @@ static int test_no_shared_qgroup(struct btrfs_root *root,
return -EINVAL;
}
ret = btrfs_find_all_roots(&trans, fs_info, nodesize, 0, &new_roots, false);
ret = btrfs_find_all_roots(&ctx, false);
if (ret) {
ulist_free(old_roots);
test_err("couldn't find old roots: %d", ret);
return ret;
}
new_roots = ctx.roots;
ctx.roots = NULL;
ret = btrfs_qgroup_account_extent(&trans, nodesize, nodesize, old_roots,
new_roots);
@ -304,6 +317,7 @@ static int test_no_shared_qgroup(struct btrfs_root *root,
static int test_multiple_refs(struct btrfs_root *root,
u32 sectorsize, u32 nodesize)
{
struct btrfs_backref_walk_ctx ctx = { 0 };
struct btrfs_trans_handle trans;
struct btrfs_fs_info *fs_info = root->fs_info;
struct ulist *old_roots = NULL;
@ -324,11 +338,17 @@ static int test_multiple_refs(struct btrfs_root *root,
return ret;
}
ret = btrfs_find_all_roots(&trans, fs_info, nodesize, 0, &old_roots, false);
ctx.bytenr = nodesize;
ctx.trans = &trans;
ctx.fs_info = fs_info;
ret = btrfs_find_all_roots(&ctx, false);
if (ret) {
test_err("couldn't find old roots: %d", ret);
return ret;
}
old_roots = ctx.roots;
ctx.roots = NULL;
ret = insert_normal_tree_ref(root, nodesize, nodesize, 0,
BTRFS_FS_TREE_OBJECTID);
@ -337,12 +357,14 @@ static int test_multiple_refs(struct btrfs_root *root,
return ret;
}
ret = btrfs_find_all_roots(&trans, fs_info, nodesize, 0, &new_roots, false);
ret = btrfs_find_all_roots(&ctx, false);
if (ret) {
ulist_free(old_roots);
test_err("couldn't find old roots: %d", ret);
return ret;
}
new_roots = ctx.roots;
ctx.roots = NULL;
ret = btrfs_qgroup_account_extent(&trans, nodesize, nodesize, old_roots,
new_roots);
@ -357,11 +379,13 @@ static int test_multiple_refs(struct btrfs_root *root,
return -EINVAL;
}
ret = btrfs_find_all_roots(&trans, fs_info, nodesize, 0, &old_roots, false);
ret = btrfs_find_all_roots(&ctx, false);
if (ret) {
test_err("couldn't find old roots: %d", ret);
return ret;
}
old_roots = ctx.roots;
ctx.roots = NULL;
ret = add_tree_ref(root, nodesize, nodesize, 0,
BTRFS_FIRST_FREE_OBJECTID);
@ -370,12 +394,14 @@ static int test_multiple_refs(struct btrfs_root *root,
return ret;
}
ret = btrfs_find_all_roots(&trans, fs_info, nodesize, 0, &new_roots, false);
ret = btrfs_find_all_roots(&ctx, false);
if (ret) {
ulist_free(old_roots);
test_err("couldn't find old roots: %d", ret);
return ret;
}
new_roots = ctx.roots;
ctx.roots = NULL;
ret = btrfs_qgroup_account_extent(&trans, nodesize, nodesize, old_roots,
new_roots);
@ -396,11 +422,13 @@ static int test_multiple_refs(struct btrfs_root *root,
return -EINVAL;
}
ret = btrfs_find_all_roots(&trans, fs_info, nodesize, 0, &old_roots, false);
ret = btrfs_find_all_roots(&ctx, false);
if (ret) {
test_err("couldn't find old roots: %d", ret);
return ret;
}
old_roots = ctx.roots;
ctx.roots = NULL;
ret = remove_extent_ref(root, nodesize, nodesize, 0,
BTRFS_FIRST_FREE_OBJECTID);
@ -409,12 +437,14 @@ static int test_multiple_refs(struct btrfs_root *root,
return ret;
}
ret = btrfs_find_all_roots(&trans, fs_info, nodesize, 0, &new_roots, false);
ret = btrfs_find_all_roots(&ctx, false);
if (ret) {
ulist_free(old_roots);
test_err("couldn't find old roots: %d", ret);
return ret;
}
new_roots = ctx.roots;
ctx.roots = NULL;
ret = btrfs_qgroup_account_extent(&trans, nodesize, nodesize, old_roots,
new_roots);