btrfs: calculate file system wide queue limit for zoned mode

To be able to split a write into properly sized zone append commands,
we need a queue_limits structure that contains the least common
denominator suitable for all devices.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/fs.h b/fs/btrfs/fs.h
index 3d8156fc8523f253ba33464a8e259528ef7b8fee..4c477eae689148dd59c45514eb2069a073d08155 100644 (file)
--- a/fs/btrfs/fs.h
+++ b/fs/btrfs/fs.h
@@ -3,6 +3,7 @@
 #ifndef BTRFS_FS_H
 #define BTRFS_FS_H
 
+#include <linux/blkdev.h>
 #include <linux/fs.h>
 #include <linux/btrfs_tree.h>
 #include <linux/sizes.h>
@@ -748,8 +749,10 @@ struct btrfs_fs_info {
         */
        u64 zone_size;
 
-       /* Max size to emit ZONE_APPEND write command */
+       /* Constraints for ZONE_APPEND commands: */
+       struct queue_limits limits;
        u64 max_zone_append_size;
+
        struct mutex zoned_meta_io_lock;
        spinlock_t treelog_bg_lock;
        u64 treelog_bg;

diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c
index 5bf67c3c9f846f859472c1625cd451df4289c40c..bcbe63ebd693ddcb5dbb45e9f1eac88842cf2ca4 100644 (file)
--- a/fs/btrfs/zoned.c
+++ b/fs/btrfs/zoned.c
@@ -421,25 +421,6 @@ int btrfs_get_dev_zone_info(struct btrfs_device *device, bool populate_cache)
        nr_sectors = bdev_nr_sectors(bdev);
        zone_info->zone_size_shift = ilog2(zone_info->zone_size);
        zone_info->nr_zones = nr_sectors >> ilog2(zone_sectors);
-       /*
-        * We limit max_zone_append_size also by max_segments *
-        * PAGE_SIZE. Technically, we can have multiple pages per segment. But,
-        * since btrfs adds the pages one by one to a bio, and btrfs cannot
-        * increase the metadata reservation even if it increases the number of
-        * extents, it is safe to stick with the limit.
-        *
-        * With the zoned emulation, we can have non-zoned device on the zoned
-        * mode. In this case, we don't have a valid max zone append size. So,
-        * use max_segments * PAGE_SIZE as the pseudo max_zone_append_size.
-        */
-       if (bdev_is_zoned(bdev)) {
-               zone_info->max_zone_append_size = min_t(u64,
-                       (u64)bdev_max_zone_append_sectors(bdev) << SECTOR_SHIFT,
-                       (u64)bdev_max_segments(bdev) << PAGE_SHIFT);
-       } else {
-               zone_info->max_zone_append_size =
-                       (u64)bdev_max_segments(bdev) << PAGE_SHIFT;
-       }
        if (!IS_ALIGNED(nr_sectors, zone_sectors))
                zone_info->nr_zones++;
 
@@ -719,9 +700,9 @@ static int btrfs_check_for_zoned_device(struct btrfs_fs_info *fs_info)
 
 int btrfs_check_zoned_mode(struct btrfs_fs_info *fs_info)
 {
+       struct queue_limits *lim = &fs_info->limits;
        struct btrfs_device *device;
        u64 zone_size = 0;
-       u64 max_zone_append_size = 0;
        int ret;
 
        /*
@@ -731,6 +712,8 @@ int btrfs_check_zoned_mode(struct btrfs_fs_info *fs_info)
        if (!btrfs_fs_incompat(fs_info, ZONED))
                return btrfs_check_for_zoned_device(fs_info);
 
+       blk_set_stacking_limits(lim);
+
        list_for_each_entry(device, &fs_info->fs_devices->devices, dev_list) {
                struct btrfs_zoned_device_info *zone_info = device->zone_info;
 
@@ -745,10 +728,17 @@ int btrfs_check_zoned_mode(struct btrfs_fs_info *fs_info)
                                  zone_info->zone_size, zone_size);
                        return -EINVAL;
                }
-               if (!max_zone_append_size ||
-                   (zone_info->max_zone_append_size &&
-                    zone_info->max_zone_append_size < max_zone_append_size))
-                       max_zone_append_size = zone_info->max_zone_append_size;
+
+               /*
+                * With the zoned emulation, we can have non-zoned device on the
+                * zoned mode. In this case, we don't have a valid max zone
+                * append size.
+                */
+               if (bdev_is_zoned(device->bdev)) {
+                       blk_stack_limits(lim,
+                                        &bdev_get_queue(device->bdev)->limits,
+                                        0);
+               }
        }
 
        /*
@@ -769,8 +759,18 @@ int btrfs_check_zoned_mode(struct btrfs_fs_info *fs_info)
        }
 
        fs_info->zone_size = zone_size;
-       fs_info->max_zone_append_size = ALIGN_DOWN(max_zone_append_size,
-                                                  fs_info->sectorsize);
+       /*
+        * Also limit max_zone_append_size by max_segments * PAGE_SIZE.
+        * Technically, we can have multiple pages per segment. But, since
+        * we add the pages one by one to a bio, and cannot increase the
+        * metadata reservation even if it increases the number of extents, it
+        * is safe to stick with the limit.
+        */
+       fs_info->max_zone_append_size = ALIGN_DOWN(
+               min3((u64)lim->max_zone_append_sectors << SECTOR_SHIFT,
+                    (u64)lim->max_sectors << SECTOR_SHIFT,
+                    (u64)lim->max_segments << PAGE_SHIFT),
+               fs_info->sectorsize);
        fs_info->fs_devices->chunk_alloc_policy = BTRFS_CHUNK_ALLOC_ZONED;
        if (fs_info->max_zone_append_size < fs_info->max_extent_size)
                fs_info->max_extent_size = fs_info->max_zone_append_size;

diff --git a/fs/btrfs/zoned.h b/fs/btrfs/zoned.h
index bc93a740e7cf34b00868e277aa684405b8095d4e..f25f332b7728595489b0045048c74a81814127b2 100644 (file)
--- a/fs/btrfs/zoned.h
+++ b/fs/btrfs/zoned.h
@@ -20,7 +20,6 @@ struct btrfs_zoned_device_info {
         */
        u64 zone_size;
        u8  zone_size_shift;
-       u64 max_zone_append_size;
        u32 nr_zones;
        unsigned int max_active_zones;
        atomic_t active_zones_left;