This extends the readahead interface with callbacks. The old readahead
behaviour is now moved into a callback that is used by default if no
other callback is given. For a detailed description of the callbacks
see the inline comments in reada.c.
It also fixes some cases where the hook has not been called. This is
not a problem with the default callback, as it just cut some branches
from readahead. With the callback mechanism, we want a guaranteed
delivery.
This patch also makes readaheads hierarchical. A readahead can have
sub-readaheads. The idea is that the content of one tree can trigger
readaheads to other trees.
Also added is a function to cancel all outstanding requests for a
given readahead and all its sub-readas.
As the interface changes slightly, scrub has been edited to reflect
the changes.
Signed-off-by: Arne Jansen <sensille@xxxxxxx>
---
fs/btrfs/ctree.h | 37 ++++-
fs/btrfs/reada.c | 481 ++++++++++++++++++++++++++++++++++++++++++------------
fs/btrfs/scrub.c | 29 ++--
3 files changed, 420 insertions(+), 127 deletions(-)
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 8e4457e..52b8a91 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -3020,6 +3020,13 @@ int btrfs_scrub_progress(struct btrfs_root *root, u64 devid,
struct btrfs_scrub_progress *progress);
/* reada.c */
+#undef READA_DEBUG
+struct reada_extctl;
+struct reada_control;
+typedef void (*reada_cb_t)(struct btrfs_root *root, struct reada_control *rc,
+ u64 wanted_generation, struct extent_buffer *eb,
+ u64 start, int err, struct btrfs_key *top,
+ void *ctx);
struct reada_control {
struct btrfs_root *root; /* tree to prefetch */
struct btrfs_key key_start;
@@ -3027,12 +3034,34 @@ struct reada_control {
atomic_t elems;
struct kref refcnt;
wait_queue_head_t wait;
+ struct reada_control *parent;
+ reada_cb_t callback;
+#ifdef READA_DEBUG
+ int not_first;
+#endif
};
-struct reada_control *btrfs_reada_add(struct btrfs_root *root,
- struct btrfs_key *start, struct btrfs_key *end);
-int btrfs_reada_wait(void *handle);
+struct reada_control *btrfs_reada_alloc(struct reada_control *parent,
+ struct btrfs_root *root,
+ struct btrfs_key *key_start, struct btrfs_key *key_end,
+ reada_cb_t callback);
+int btrfs_reada_add(struct reada_control *parent,
+ struct btrfs_root *root,
+ struct btrfs_key *key_start, struct btrfs_key *key_end,
+ reada_cb_t callback, void *ctx,
+ struct reada_control **rcp);
+int btrfs_reada_wait(struct reada_control *handle);
void btrfs_reada_detach(void *handle);
int btree_readahead_hook(struct btrfs_root *root, struct extent_buffer *eb,
u64 start, int err);
-
+int reada_add_block(struct reada_control *rc, u64 logical,
+ struct btrfs_key *top, int level, u64 generation, void *ctx);
+void reada_control_elem_get(struct reada_control *rc);
+void reada_control_elem_put(struct reada_control *rc);
+void reada_start_machine(struct btrfs_fs_info *fs_info);
+int btrfs_reada_abort(struct btrfs_fs_info *fs_info, struct reada_control *rc);
+
+/* droptree.c */
+int btrfs_droptree_pause(struct btrfs_fs_info *fs_info);
+void btrfs_droptree_continue(struct btrfs_fs_info *fs_info);
+void droptree_drop_list(struct btrfs_fs_info *fs_info, struct list_head *list);
#endif
diff --git a/fs/btrfs/reada.c b/fs/btrfs/reada.c
index 2373b39..0d88163 100644
--- a/fs/btrfs/reada.c
+++ b/fs/btrfs/reada.c
@@ -27,18 +27,18 @@
#include "volumes.h"
#include "disk-io.h"
#include "transaction.h"
-
-#undef DEBUG
+#include "locking.h"
/*
* This is the implementation for the generic read ahead framework.
*
* To trigger a readahead, btrfs_reada_add must be called. It will start
- * a read ahead for the given range [start, end) on tree root. The returned
+ * a readahead for the given range [start, end) on tree root. The returned
* handle can either be used to wait on the readahead to finish
* (btrfs_reada_wait), or to send it to the background (btrfs_reada_detach).
+ * If no return pointer is given, the readahead is started in the background.
*
- * The read ahead works as follows:
+ * The readahead works as follows:
* On btrfs_reada_add, the root of the tree is inserted into a radix_tree.
* reada_start_machine will then search for extents to prefetch and trigger
* some reads. When a read finishes for a node, all contained node/leaf
@@ -52,6 +52,27 @@
* Any number of readaheads can be started in parallel. The read order will be
* determined globally, i.e. 2 parallel readaheads will normally finish faster
* than the 2 started one after another.
+ *
+ * In addition to the default behaviour, a callback can be passed to reada_add.
+ * This callback will be called for each completed read, in an unspecified
+ * order. This callback can then enqueue further reada requests via
+ * reada_add_block or create sub-readaheads with btrfs_reada_add (detached).
+ * The rules for custom callbacks are:
+ * - The elem count must never go to zero unless the reada is completed. So
+ * either enqueue further blocks or create sub-readaheads with itself as
+ * parent. Each sub-readahead will add one to the parent's element count.
+ * If you need to defer some work, keep the count from dropping to zero
+ * by calling reada_control_elem_get(). When finished, return it with
+ * reada_control_elem_put(). This might also free the rc.
+ * - The extent buffer passed to the callback will be read locked, spinning.
+ * - The callback is called in the context of the checksum workers
+ * - The callback is also called if the read failed. This is signaled via
+ * the err parameter. In this case the eb might be NULL. Make sure to
+ * properly update your data structures even in error cases to not leave
+ * refs anywhere.
+ *
+ * If no callback is given, the default callback is used giving the initially
+ * described behaviour.
*/
#define MAX_MIRRORS 2
@@ -60,6 +81,7 @@
struct reada_extctl {
struct list_head list;
struct reada_control *rc;
+ void *ctx;
u64 generation;
};
@@ -97,30 +119,87 @@ struct reada_machine_work {
static void reada_extent_put(struct btrfs_fs_info *, struct reada_extent *);
static void reada_control_release(struct kref *kref);
static void reada_zone_release(struct kref *kref);
-static void reada_start_machine(struct btrfs_fs_info *fs_info);
static void __reada_start_machine(struct btrfs_fs_info *fs_info);
-static int reada_add_block(struct reada_control *rc, u64 logical,
- struct btrfs_key *top, int level, u64 generation);
+/*
+ * this is the default callback for readahead. It just descends into the
+ * tree within the range given at creation. if an error occurs, just cut
+ * this part of the tree
+ */
+static void readahead_descend(struct btrfs_root *root, struct reada_control *rc,
+ u64 wanted_generation, struct extent_buffer *eb,
+ u64 start, int err, struct btrfs_key *top,
+ void *ctx)
+{
+ int nritems;
+ u64 generation;
+ int level;
+ int i;
+
+ BUG_ON(err == -EAGAIN); /* FIXME: not yet implemented, don't cancel
+ * readahead with default callback */
+
+ if (err || eb == NULL) {
+ /*
+ * this is the error case, the extent buffer has not been
+ * read correctly. We won't access anything from it and
+ * just cleanup our data structures. Effectively this will
+ * cut the branch below this node from read ahead.
+ */
+ return;
+ }
+
+ level = btrfs_header_level(eb);
+ if (level == 0) {
+ /*
+ * if this is a leaf, ignore the content.
+ */
+ return;
+ }
+
+ nritems = btrfs_header_nritems(eb);
+ generation = btrfs_header_generation(eb);
+
+ /*
+ * if the generation doesn't match, just ignore this node.
+ * This will cut off a branch from prefetch. Alternatively one could
+ * start a new (sub-) prefetch for this branch, starting again from
+ * root.
+ */
+ if (wanted_generation != generation)
+ return;
+
+ for (i = 0; i < nritems; i++) {
+ u64 n_gen;
+ struct btrfs_key key;
+ struct btrfs_key next_key;
+ u64 bytenr;
+
+ btrfs_node_key_to_cpu(eb, &key, i);
+ if (i + 1 < nritems)
+ btrfs_node_key_to_cpu(eb, &next_key, i + 1);
+ else
+ next_key = *top;
+ bytenr = btrfs_node_blockptr(eb, i);
+ n_gen = btrfs_node_ptr_generation(eb, i);
+
+ if (btrfs_comp_cpu_keys(&key, &rc->key_end) < 0 &&
+ btrfs_comp_cpu_keys(&next_key, &rc->key_start) > 0)
+ reada_add_block(rc, bytenr, &next_key,
+ level - 1, n_gen, ctx);
+ }
+}
-/* recurses */
/* in case of err, eb might be NULL */
static int __readahead_hook(struct btrfs_root *root, struct extent_buffer *eb,
u64 start, int err)
{
- int level = 0;
- int nritems;
- int i;
- u64 bytenr;
- u64 generation;
struct reada_extent *re;
struct btrfs_fs_info *fs_info = root->fs_info;
struct list_head list;
unsigned long index = start >> PAGE_CACHE_SHIFT;
struct btrfs_device *for_dev;
-
- if (eb)
- level = btrfs_header_level(eb);
+ struct reada_extctl *rec;
/* find extent */
spin_lock(&fs_info->reada_lock);
@@ -142,65 +221,21 @@ static int __readahead_hook(struct btrfs_root *root, struct extent_buffer *eb,
re->scheduled_for = NULL;
spin_unlock(&re->lock);
- if (err == 0) {
- nritems = level ? btrfs_header_nritems(eb) : 0;
- generation = btrfs_header_generation(eb);
- /*
- * FIXME: currently we just set nritems to 0 if this is a leaf,
- * effectively ignoring the content. In a next step we could
- * trigger more readahead depending from the content, e.g.
- * fetch the checksums for the extents in the leaf.
- */
- } else {
+ /*
+ * call hooks for all registered readaheads
+ */
+ list_for_each_entry(rec, &list, list) {
+ btrfs_tree_read_lock(eb);
/*
- * this is the error case, the extent buffer has not been
- * read correctly. We won't access anything from it and
- * just cleanup our data structures. Effectively this will
- * cut the branch below this node from read ahead.
+ * we set the lock to blocking, as the callback might want to
+ * sleep on allocations.
*/
- nritems = 0;
- generation = 0;
+ btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
+ rec->rc->callback(root, rec->rc, rec->generation, eb, start,
+ err, &re->top, rec->ctx);
+ btrfs_tree_read_unlock_blocking(eb);
}
- for (i = 0; i < nritems; i++) {
- struct reada_extctl *rec;
- u64 n_gen;
- struct btrfs_key key;
- struct btrfs_key next_key;
-
- btrfs_node_key_to_cpu(eb, &key, i);
- if (i + 1 < nritems)
- btrfs_node_key_to_cpu(eb, &next_key, i + 1);
- else
- next_key = re->top;
- bytenr = btrfs_node_blockptr(eb, i);
- n_gen = btrfs_node_ptr_generation(eb, i);
-
- list_for_each_entry(rec, &list, list) {
- struct reada_control *rc = rec->rc;
-
- /*
- * if the generation doesn't match, just ignore this
- * extctl. This will probably cut off a branch from
- * prefetch. Alternatively one could start a new (sub-)
- * prefetch for this branch, starting again from root.
- * FIXME: move the generation check out of this loop
- */
-#ifdef DEBUG
- if (rec->generation != generation) {
- printk(KERN_DEBUG "generation mismatch for "
- "(%llu,%d,%llu) %llu != %llu\n",
- key.objectid, key.type, key.offset,
- rec->generation, generation);
- }
-#endif
- if (rec->generation == generation &&
- btrfs_comp_cpu_keys(&key, &rc->key_end) < 0 &&
- btrfs_comp_cpu_keys(&next_key, &rc->key_start) > 0)
- reada_add_block(rc, bytenr, &next_key,
- level - 1, n_gen);
- }
- }
/*
* free extctl records
*/
@@ -213,12 +248,7 @@ static int __readahead_hook(struct btrfs_root *root, struct extent_buffer *eb,
rc = rec->rc;
kfree(rec);
- kref_get(&rc->refcnt);
- if (atomic_dec_and_test(&rc->elems)) {
- kref_put(&rc->refcnt, reada_control_release);
- wake_up(&rc->wait);
- }
- kref_put(&rc->refcnt, reada_control_release);
+ reada_control_elem_put(rc);
reada_extent_put(fs_info, re); /* one ref for each entry */
}
@@ -352,7 +382,8 @@ again:
blocksize = btrfs_level_size(root, level);
re->logical = logical;
re->blocksize = blocksize;
- re->top = *top;
+ if (top)
+ re->top = *top;
INIT_LIST_HEAD(&re->extctl);
spin_lock_init(&re->lock);
kref_init(&re->refcnt);
@@ -503,6 +534,47 @@ static void reada_extent_put(struct btrfs_fs_info *fs_info,
kfree(re);
}
+void reada_control_elem_get(struct reada_control *rc)
+{
+#ifndef READA_DEBUG
+ atomic_inc(&rc->elems);
+#else
+ int new = atomic_inc_return(&rc->elems);
+
+ if (rc->not_first && new == 1) {
+ /*
+ * warn if we try to get an elem although it
+ * was already down to zero
+ */
+ WARN_ON(1);
+ }
+ rc->not_first = 1;
+#endif
+}
+
+void reada_control_elem_put(struct reada_control *rc)
+{
+ struct reada_control *next_rc;
+
+ do {
+ next_rc = NULL;
+ kref_get(&rc->refcnt);
+ if (atomic_dec_and_test(&rc->elems)) {
+ /*
+ * when the last elem is finished, wake all
+ * waiters. Also, if we have a parent, remove
+ * our element from there and wake the waiters.
+ * Walk up the chain of parents as long as
+ * we finish the last elem. Drop our ref.
+ */
+ kref_put(&rc->refcnt, reada_control_release);
+ wake_up(&rc->wait);
+ next_rc = rc->parent;
+ }
+ kref_put(&rc->refcnt, reada_control_release);
+ } while ((rc = next_rc));
+}
+
static void reada_zone_release(struct kref *kref)
{
struct reada_zone *zone = container_of(kref, struct reada_zone, refcnt);
@@ -521,12 +593,87 @@ static void reada_control_release(struct kref *kref)
kfree(rc);
}
-static int reada_add_block(struct reada_control *rc, u64 logical,
- struct btrfs_key *top, int level, u64 generation)
+/*
+ * context to pass from reada_add_block to worker in case the extent is
+ * already uptodate in memory
+ */
+struct reada_uptodate_ctx {
+ struct btrfs_key top;
+ struct extent_buffer *eb;
+ struct reada_control *rc;
+ u64 logical;
+ u64 generation;
+ void *ctx;
+ struct btrfs_work work;
+};
+
+/* worker for immediate processing of uptodate blocks */
+static void reada_add_block_uptodate(struct btrfs_work *work)
+{
+ struct reada_uptodate_ctx *ruc;
+
+ ruc = container_of(work, struct reada_uptodate_ctx, work);
+
+ btrfs_tree_read_lock(ruc->eb);
+ /*
+ * we set the lock to blocking, as the callback might want to sleep
+ * on allocations.
+ */
+ btrfs_set_lock_blocking_rw(ruc->eb, BTRFS_READ_LOCK);
+ ruc->rc->callback(ruc->rc->root, ruc->rc, ruc->generation, ruc->eb,
+ ruc->logical, 0, &ruc->top, ruc->ctx);
+ btrfs_tree_read_unlock_blocking(ruc->eb);
+
+ reada_control_elem_put(ruc->rc);
+ free_extent_buffer(ruc->eb);
+ kfree(ruc);
+}
+
+int reada_add_block(struct reada_control *rc, u64 logical,
+ struct btrfs_key *top, int level, u64 generation,
+ void *ctx)
{
struct btrfs_root *root = rc->root;
struct reada_extent *re;
struct reada_extctl *rec;
+ struct extent_buffer *eb;
+ struct inode *btree_inode;
+
+ /*
+ * first check if the buffer is already uptodate in memory. In this
+ * case it wouldn't make much sense to go through the reada dance.
+ * Instead process it as soon as possible, but in worker context to
+ * prevent recursion.
+ */
+ eb = btrfs_find_tree_block(root, logical,
+ btrfs_level_size(root, level));
+ btree_inode = eb->first_page->mapping->host;
+
+ if (eb && btrfs_buffer_uptodate(eb, generation)) {
+ struct reada_uptodate_ctx *ruc;
+
+ ruc = kzalloc(sizeof(*ruc), GFP_NOFS);
+ if (!ruc) {
+ free_extent_buffer(eb);
+ return -1;
+ }
+ ruc->rc = rc;
+ ruc->ctx = ctx;
+ ruc->generation = generation;
+ ruc->logical = logical;
+ ruc->eb = eb;
+ if (top)
+ ruc->top = *top;
+ ruc->work.func = reada_add_block_uptodate;
+ reada_control_elem_get(rc);
+
+ btrfs_queue_worker(&root->fs_info->readahead_workers,
+ &ruc->work);
+
+ return 0;
+ }
+ if (eb)
+ free_extent_buffer(eb);
re = reada_find_extent(root, logical, top, level); /* takes one ref */
if (!re)
@@ -539,14 +686,17 @@ static int reada_add_block(struct reada_control *rc, u64 logical,
}
rec->rc = rc;
+ rec->ctx = ctx;
rec->generation = generation;
- atomic_inc(&rc->elems);
+ reada_control_elem_get(rc);
spin_lock(&re->lock);
list_add_tail(&rec->list, &re->extctl);
spin_unlock(&re->lock);
- /* leave the ref on the extent */
+ reada_start_machine(root->fs_info);
+
+ /* leave the ref on re */
return 0;
}
@@ -750,10 +900,14 @@ static void __reada_start_machine(struct btrfs_fs_info *fs_info)
reada_start_machine(fs_info);
}
-static void reada_start_machine(struct btrfs_fs_info *fs_info)
+void reada_start_machine(struct btrfs_fs_info *fs_info)
{
struct reada_machine_work *rmw;
+ /*
+ * FIXME if there are still requests in flight, we don't need to
+ * kick a worker. Add a check to prevent unnecessary work
+ */
rmw = kzalloc(sizeof(*rmw), GFP_NOFS);
if (!rmw) {
/* FIXME we cannot handle this properly right now */
@@ -765,7 +919,7 @@ static void reada_start_machine(struct btrfs_fs_info *fs_info)
btrfs_queue_worker(&fs_info->readahead_workers, &rmw->work);
}
-#ifdef DEBUG
+#ifdef READA_DEBUG
static void dump_devs(struct btrfs_fs_info *fs_info, int all)
{
struct btrfs_device *device;
@@ -870,15 +1024,49 @@ static void dump_devs(struct btrfs_fs_info *fs_info, int all)
#endif
/*
- * interface
+ * if parent is given, the caller has to hold a ref on parent
*/
-struct reada_control *btrfs_reada_add(struct btrfs_root *root,
- struct btrfs_key *key_start, struct btrfs_key *key_end)
+struct reada_control *btrfs_reada_alloc(struct reada_control *parent,
+ struct btrfs_root *root,
+ struct btrfs_key *key_start, struct btrfs_key *key_end,
+ reada_cb_t callback)
+{
+ struct reada_control *rc;
+
+ rc = kzalloc(sizeof(*rc), GFP_NOFS);
+ if (!rc)
+ return ERR_PTR(-ENOMEM);
+
+ rc->root = root;
+ rc->parent = parent;
+ rc->callback = callback ? callback : readahead_descend;
+ if (key_start)
+ rc->key_start = *key_start;
+ if (key_end)
+ rc->key_end = *key_end;
+ atomic_set(&rc->elems, 0);
+ init_waitqueue_head(&rc->wait);
+ kref_init(&rc->refcnt);
+ if (parent) {
+ /*
+ * we just add one element to the parent as long as we're
+ * not finished
+ */
+ reada_control_elem_get(parent);
+ }
+
+ return rc;
+}
+
+int btrfs_reada_add(struct reada_control *parent, struct btrfs_root *root,
+ struct btrfs_key *key_start, struct btrfs_key *key_end,
+ reada_cb_t callback, void *ctx, struct reada_control **rcp)
{
struct reada_control *rc;
u64 start;
u64 generation;
int level;
+ int ret;
struct extent_buffer *node;
static struct btrfs_key max_key = {
.objectid = (u64)-1,
@@ -886,17 +1074,18 @@ struct reada_control *btrfs_reada_add(struct btrfs_root *root,
.offset = (u64)-1
};
- rc = kzalloc(sizeof(*rc), GFP_NOFS);
+ rc = btrfs_reada_alloc(parent, root, key_start, key_end, callback);
if (!rc)
- return ERR_PTR(-ENOMEM);
+ return -ENOMEM;
- rc->root = root;
- rc->key_start = *key_start;
- rc->key_end = *key_end;
- atomic_set(&rc->elems, 0);
- init_waitqueue_head(&rc->wait);
- kref_init(&rc->refcnt);
- kref_get(&rc->refcnt); /* one ref for having elements */
+ if (rcp) {
+ *rcp = rc;
+ /*
+ * as we return the rc, get an addition ref on it for
+ * the caller
+ */
+ kref_get(&rc->refcnt);
+ }
node = btrfs_root_node(root);
start = node->start;
@@ -904,35 +1093,36 @@ struct reada_control *btrfs_reada_add(struct btrfs_root *root,
generation = btrfs_header_generation(node);
free_extent_buffer(node);
- reada_add_block(rc, start, &max_key, level, generation);
+ ret = reada_add_block(rc, start, &max_key, level, generation, ctx);
reada_start_machine(root->fs_info);
- return rc;
+ return ret;
}
-#ifdef DEBUG
-int btrfs_reada_wait(void *handle)
+#ifdef READA_DEBUG
+int btrfs_reada_wait(struct reada_control *rc)
{
- struct reada_control *rc = handle;
+ struct btrfs_fs_info *fs_info = rc->root->fs_info;
+ int i;
while (atomic_read(&rc->elems)) {
wait_event_timeout(rc->wait, atomic_read(&rc->elems) == 0,
- 5 * HZ);
- dump_devs(rc->root->fs_info, rc->elems < 10 ? 1 : 0);
+ 1 * HZ);
+ dump_devs(fs_info, atomic_read(&rc->elems) < 10 ? 1 : 0);
+ printk(KERN_DEBUG "reada_wait on %p: %d elems\n", rc,
+ atomic_read(&rc->elems));
}
- dump_devs(rc->root->fs_info, rc->elems < 10 ? 1 : 0);
+ dump_devs(fs_info, atomic_read(&rc->elems) < 10 ? 1 : 0);
kref_put(&rc->refcnt, reada_control_release);
return 0;
}
#else
-int btrfs_reada_wait(void *handle)
+int btrfs_reada_wait(struct reada_control *rc)
{
- struct reada_control *rc = handle;
-
while (atomic_read(&rc->elems)) {
wait_event(rc->wait, atomic_read(&rc->elems) == 0);
}
@@ -949,3 +1139,80 @@ void btrfs_reada_detach(void *handle)
kref_put(&rc->refcnt, reada_control_release);
}
+
+/*
+ * abort all readahead for a specific reada_control
+ * this function does not wait for outstanding requests to finish, so
+ * when it returns, the abort is not fully complete. This function will
+ * cancel all currently enqueued readaheads for the given rc and all children
+ * of it.
+ */
+int btrfs_reada_abort(struct btrfs_fs_info *fs_info, struct reada_control *rc)
+{
+ struct reada_extent *re = NULL;
+ struct list_head list;
+ int ret;
+ u64 logical = 0;
+ struct reada_extctl *rec;
+ struct reada_extctl *tmp;
+
+ INIT_LIST_HEAD(&list);
+
+ while (1) {
+ spin_lock(&fs_info->reada_lock);
+ ret = radix_tree_gang_lookup(&fs_info->reada_tree, (void **)&re,
+ logical >> PAGE_CACHE_SHIFT, 1);
+ if (ret == 1)
+ kref_get(&re->refcnt);
+ spin_unlock(&fs_info->reada_lock);
+
+ if (ret != 1)
+ break;
+
+ /*
+ * take out all extctls that should get deleted into another
+ * list
+ */
+ spin_lock(&re->lock);
+ if (re->scheduled_for) {
+ spin_unlock(&re->lock);
+ goto next;
+ }
+
+ list_for_each_entry_safe(rec, tmp, &re->extctl, list) {
+ struct reada_control *it;
+
+ for (it = rec->rc; it; it = it->parent) {
+ if (it == rc) {
+ list_move(&rec->list, &list);
+ break;
+ }
+ }
+ }
+ spin_unlock(&re->lock);
+
+ /*
+ * now cancel all extctls in the list
+ */
+ while (!list_empty(&list)) {
+ struct reada_control *tmp_rc;
+
+ rec = list_first_entry(&list, struct reada_extctl,
+ list);
+ rec->rc->callback(rec->rc->root, rec->rc, 0, NULL,
+ re->logical,
+ -EAGAIN, &re->top, rec->ctx);
+ list_del(&rec->list);
+ tmp_rc = rec->rc;
+ kfree(rec);
+
+ reada_control_elem_put(tmp_rc);
+ reada_extent_put(fs_info, re);
+ }
+next:
+ logical = re->logical + PAGE_CACHE_SIZE;
+ reada_extent_put(fs_info, re); /* our ref */
+ }
+
+ return 1;
+}
diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index abc0fbf..80140a8 100644
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -1136,7 +1136,6 @@ static noinline_for_stack int scrub_stripe(struct scrub_dev *sdev,
u64 generation;
int mirror_num;
struct reada_control *reada1;
- struct reada_control *reada2;
struct btrfs_key key_start;
struct btrfs_key key_end;
@@ -1189,23 +1188,21 @@ static noinline_for_stack int scrub_stripe(struct scrub_dev *sdev,
key_start.objectid = logical;
key_start.type = BTRFS_EXTENT_ITEM_KEY;
key_start.offset = (u64)0;
+ key_end = key_start;
key_end.objectid = base + offset + nstripes * increment;
- key_end.type = BTRFS_EXTENT_ITEM_KEY;
- key_end.offset = (u64)0;
- reada1 = btrfs_reada_add(root, &key_start, &key_end);
-
- key_start.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
- key_start.type = BTRFS_EXTENT_CSUM_KEY;
- key_start.offset = logical;
- key_end.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
- key_end.type = BTRFS_EXTENT_CSUM_KEY;
- key_end.offset = base + offset + nstripes * increment;
- reada2 = btrfs_reada_add(csum_root, &key_start, &key_end);
-
- if (!IS_ERR(reada1))
+ ret = btrfs_reada_add(NULL, root, &key_start, &key_end,
+ NULL, NULL, &reada1);
+ /* if readahead fails, we just go ahead without it */
+ if (ret == 0) {
+ key_start.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
+ key_start.type = BTRFS_EXTENT_CSUM_KEY;
+ key_start.offset = logical;
+ key_end = key_start;
+ key_end.offset = base + offset + nstripes * increment;
+ ret = btrfs_reada_add(reada1, csum_root, &key_start,
+ &key_end, NULL, NULL, NULL);
btrfs_reada_wait(reada1);
- if (!IS_ERR(reada2))
- btrfs_reada_wait(reada2);
+ }
mutex_lock(&fs_info->scrub_lock);
while (atomic_read(&fs_info->scrub_pause_req)) {
--
1.7.3.4
--
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