@@ -72,7 +72,7 @@ struct reada_extent {
spinlock_t lock;
struct reada_zone *zones[BTRFS_MAX_MIRRORS];
int nzones;
- struct btrfs_device *scheduled_for;
+ int scheduled;
};
struct reada_zone {
@@ -118,7 +118,6 @@ static void __readahead_hook(struct btrfs_fs_info *fs_info,
u64 bytenr;
u64 generation;
struct list_head list;
- struct btrfs_device *for_dev;
if (eb)
level = btrfs_header_level(eb);
@@ -129,8 +128,7 @@ static void __readahead_hook(struct btrfs_fs_info *fs_info,
* don't need the lock anymore
*/
list_replace_init(&re->extctl, &list);
- for_dev = re->scheduled_for;
- re->scheduled_for = NULL;
+ re->scheduled = 0;
spin_unlock(&re->lock);
/*
@@ -215,9 +213,6 @@ cleanup:
reada_extent_put(fs_info, re); /* one ref for each entry */
}
- if (for_dev)
- atomic_dec(&for_dev->reada_in_flight);
-
return;
}
@@ -543,8 +538,6 @@ static void reada_extent_put(struct btrfs_fs_info *fs_info,
kref_put(&zone->refcnt, reada_zone_release);
spin_unlock(&fs_info->reada_lock);
}
- if (re->scheduled_for)
- atomic_dec(&re->scheduled_for->reada_in_flight);
kfree(re);
}
@@ -710,12 +703,12 @@ static int reada_start_machine_dev(struct btrfs_fs_info *fs_info,
spin_unlock(&fs_info->reada_lock);
spin_lock(&re->lock);
- if (re->scheduled_for || list_empty(&re->extctl)) {
+ if (re->scheduled || list_empty(&re->extctl)) {
spin_unlock(&re->lock);
reada_extent_put(fs_info, re);
return 0;
}
- re->scheduled_for = dev;
+ re->scheduled = 1;
spin_unlock(&re->lock);
/*
@@ -740,6 +733,7 @@ static int reada_start_machine_dev(struct btrfs_fs_info *fs_info,
if (eb)
free_extent_buffer(eb);
+ atomic_dec(&dev->reada_in_flight);
reada_extent_put(fs_info, re);
return 1;
@@ -864,10 +858,9 @@ static void dump_devs(struct btrfs_fs_info *fs_info, int all)
if (ret == 0)
break;
printk(KERN_DEBUG
- " re: logical %llu size %u empty %d for %lld",
+ " re: logical %llu size %u empty %d scheduled %d",
re->logical, fs_info->tree_root->nodesize,
- list_empty(&re->extctl), re->scheduled_for ?
- re->scheduled_for->devid : -1);
+ list_empty(&re->extctl), re->scheduled);
for (i = 0; i < re->nzones; ++i) {
printk(KERN_CONT " zone %llu-%llu devs",
@@ -894,15 +887,14 @@ static void dump_devs(struct btrfs_fs_info *fs_info, int all)
index, 1);
if (ret == 0)
break;
- if (!re->scheduled_for) {
+ if (!re->scheduled) {
index = (re->logical >> PAGE_CACHE_SHIFT) + 1;
continue;
}
printk(KERN_DEBUG
- "re: logical %llu size %u list empty %d for %lld",
+ "re: logical %llu size %u list empty %d scheduled %d",
re->logical, fs_info->tree_root->nodesize,
- list_empty(&re->extctl),
- re->scheduled_for ? re->scheduled_for->devid : -1);
+ list_empty(&re->extctl), re->scheduled);
for (i = 0; i < re->nzones; ++i) {
printk(KERN_CONT " zone %llu-%llu devs",
re->zones[i]->start,
No need to decrease dev->reada_in_flight in __readahead_hook()'s internal and reada_extent_put(). reada_extent_put() have no chance to decrease dev->reada_in_flight in free operation, because reada_extent have additional refcnt when scheduled to a dev. We can put inc and dec operation for dev->reada_in_flight to one place instead to make logic simple and safe, and move useless reada_extent->scheduled_for to a bool flag instead. Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com> --- fs/btrfs/reada.c | 28 ++++++++++------------------ 1 file changed, 10 insertions(+), 18 deletions(-)