[PATCH STABLE 5.15 0/5] btrfs: zoned: backport max_extent_size fix

[PATCH STABLE 5.15 0/5] btrfs: zoned: backport max_extent_size fix

[Naohiro Aota]

These patches are backport for the 5.15 branch.

This series backports fixes for expecting the number of on-going write
extents on zoned mode.

It picks up patches 1 to 3 for the dependencies of patches 4 and 5.

Christoph Hellwig (1):
  block: add a bdev_max_zone_append_sectors helper

Naohiro Aota (4):
  block: add bdev_max_segments() helper
  btrfs: zoned: revive max_zone_append_bytes
  btrfs: replace BTRFS_MAX_EXTENT_SIZE with fs_info->max_extent_size
  btrfs: convert count_max_extents() to use fs_info->max_extent_size

 drivers/nvme/target/zns.c |  3 +--
 fs/btrfs/ctree.h          | 29 +++++++++++++++++++++--------
 fs/btrfs/delalloc-space.c |  6 +++---
 fs/btrfs/disk-io.c        |  2 ++
 fs/btrfs/extent_io.c      |  4 +++-
 fs/btrfs/inode.c          | 22 ++++++++++++----------
 fs/btrfs/zoned.c          | 20 ++++++++++++++++++++
 fs/btrfs/zoned.h          |  1 +
 fs/zonefs/super.c         |  3 +--
 include/linux/blkdev.h    | 11 +++++++++++
 10 files changed, 75 insertions(+), 26 deletions(-)

-- 
2.37.2

[PATCH STABLE 5.15 1/5] block: add a bdev_max_zone_append_sectors helper

[Naohiro Aota]

From: Christoph Hellwig <hch@lst.de>

commit 2aba0d19f4d8c8929b4b3b94a9cfde2aa20e6ee2 upstream

Add a helper to check the max supported sectors for zone append based on
the block_device instead of having to poke into the block layer internal
request_queue.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20220415045258.199825-16-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
 drivers/nvme/target/zns.c | 3 +--
 fs/zonefs/super.c         | 3 +--
 include/linux/blkdev.h    | 6 ++++++
 3 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/drivers/nvme/target/zns.c b/drivers/nvme/target/zns.c
index 46bc30fe85d2..235553337fb2 100644
--- a/drivers/nvme/target/zns.c
+++ b/drivers/nvme/target/zns.c
@@ -34,8 +34,7 @@ static int validate_conv_zones_cb(struct blk_zone *z,
 
 bool nvmet_bdev_zns_enable(struct nvmet_ns *ns)
 {
-	struct request_queue *q = ns->bdev->bd_disk->queue;
-	u8 zasl = nvmet_zasl(queue_max_zone_append_sectors(q));
+	u8 zasl = nvmet_zasl(bdev_max_zone_append_sectors(ns->bdev));
 	struct gendisk *bd_disk = ns->bdev->bd_disk;
 	int ret;
 
diff --git a/fs/zonefs/super.c b/fs/zonefs/super.c
index ecf564d150b3..f8feaed0b54d 100644
--- a/fs/zonefs/super.c
+++ b/fs/zonefs/super.c
@@ -723,13 +723,12 @@ static ssize_t zonefs_file_dio_append(struct kiocb *iocb, struct iov_iter *from)
 	struct inode *inode = file_inode(iocb->ki_filp);
 	struct zonefs_inode_info *zi = ZONEFS_I(inode);
 	struct block_device *bdev = inode->i_sb->s_bdev;
-	unsigned int max;
+	unsigned int max = bdev_max_zone_append_sectors(bdev);
 	struct bio *bio;
 	ssize_t size;
 	int nr_pages;
 	ssize_t ret;
 
-	max = queue_max_zone_append_sectors(bdev_get_queue(bdev));
 	max = ALIGN_DOWN(max << SECTOR_SHIFT, inode->i_sb->s_blocksize);
 	iov_iter_truncate(from, max);
 
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 8863b4a378af..2f4ba6e345d5 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1387,6 +1387,12 @@ static inline unsigned int queue_max_zone_append_sectors(const struct request_qu
 	return min(l->max_zone_append_sectors, l->max_sectors);
 }
 
+static inline unsigned int
+bdev_max_zone_append_sectors(struct block_device *bdev)
+{
+	return queue_max_zone_append_sectors(bdev_get_queue(bdev));
+}
+
 static inline unsigned queue_logical_block_size(const struct request_queue *q)
 {
 	int retval = 512;
-- 
2.37.2

[PATCH STABLE 5.15 2/5] block: add bdev_max_segments() helper

[Naohiro Aota]

commit 65ea1b66482f415d51cd46515b02477257330339 upstream

Add bdev_max_segments() like other queue parameters.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
---
 include/linux/blkdev.h | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 2f4ba6e345d5..67344dfe07a7 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1393,6 +1393,11 @@ bdev_max_zone_append_sectors(struct block_device *bdev)
 	return queue_max_zone_append_sectors(bdev_get_queue(bdev));
 }
 
+static inline unsigned int bdev_max_segments(struct block_device *bdev)
+{
+	return queue_max_segments(bdev_get_queue(bdev));
+}
+
 static inline unsigned queue_logical_block_size(const struct request_queue *q)
 {
 	int retval = 512;
-- 
2.37.2

[PATCH STABLE 5.15 3/5] btrfs: zoned: revive max_zone_append_bytes

[Naohiro Aota]

commit c2ae7b772ef4e86c5ddf3fd47bf59045ae96a414 upstream

This patch is basically a revert of commit 5a80d1c6a270 ("btrfs: zoned:
remove max_zone_append_size logic"), but without unnecessary ASSERT and
check. The max_zone_append_size will be used as a hint to estimate the
number of extents to cover delalloc/writeback region in the later commits.

The size of a ZONE APPEND bio is also limited by queue_max_segments(), so
this commit considers it to calculate max_zone_append_size. Technically, a
bio can be larger than queue_max_segments() * PAGE_SIZE if the pages are
contiguous. But, it is safe to consider "queue_max_segments() * PAGE_SIZE"
as an upper limit of an extent size to calculate the number of extents
needed to write data.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
---
 fs/btrfs/ctree.h |  2 ++
 fs/btrfs/zoned.c | 17 +++++++++++++++++
 fs/btrfs/zoned.h |  1 +
 3 files changed, 20 insertions(+)

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index d1838de0b39c..099c30477cf2 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1017,6 +1017,8 @@ struct btrfs_fs_info {
 		u64 zoned;
 	};
 
+	/* Max size to emit ZONE_APPEND write command */
+	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 fc791f7c7142..bfbceb94c4e2 100644
--- a/fs/btrfs/zoned.c
+++ b/fs/btrfs/zoned.c
@@ -386,6 +386,16 @@ 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.
+	 */
+	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);
 	if (!IS_ALIGNED(nr_sectors, zone_sectors))
 		zone_info->nr_zones++;
 
@@ -570,6 +580,7 @@ int btrfs_check_zoned_mode(struct btrfs_fs_info *fs_info)
 	u64 zoned_devices = 0;
 	u64 nr_devices = 0;
 	u64 zone_size = 0;
+	u64 max_zone_append_size = 0;
 	const bool incompat_zoned = btrfs_fs_incompat(fs_info, ZONED);
 	int ret = 0;
 
@@ -605,6 +616,11 @@ int btrfs_check_zoned_mode(struct btrfs_fs_info *fs_info)
 				ret = -EINVAL;
 				goto out;
 			}
+			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;
 		}
 		nr_devices++;
 	}
@@ -654,6 +670,7 @@ int btrfs_check_zoned_mode(struct btrfs_fs_info *fs_info)
 	}
 
 	fs_info->zone_size = zone_size;
+	fs_info->max_zone_append_size = max_zone_append_size;
 	fs_info->fs_devices->chunk_alloc_policy = BTRFS_CHUNK_ALLOC_ZONED;
 
 	/*
diff --git a/fs/btrfs/zoned.h b/fs/btrfs/zoned.h
index 574490ea2cc8..1ef493fcd504 100644
--- a/fs/btrfs/zoned.h
+++ b/fs/btrfs/zoned.h
@@ -23,6 +23,7 @@ struct btrfs_zoned_device_info {
 	 */
 	u64 zone_size;
 	u8  zone_size_shift;
+	u64 max_zone_append_size;
 	u32 nr_zones;
 	unsigned long *seq_zones;
 	unsigned long *empty_zones;
-- 
2.37.2

[PATCH STABLE 5.15 4/5] btrfs: replace BTRFS_MAX_EXTENT_SIZE with fs_info->max_extent_size

[Naohiro Aota]

commit f7b12a62f008a3041f42f2426983e59a6a0a3c59 upstream

On zoned filesystem, data write out is limited by max_zone_append_size,
and a large ordered extent is split according the size of a bio. OTOH,
the number of extents to be written is calculated using
BTRFS_MAX_EXTENT_SIZE, and that estimated number is used to reserve the
metadata bytes to update and/or create the metadata items.

The metadata reservation is done at e.g, btrfs_buffered_write() and then
released according to the estimation changes. Thus, if the number of extent
increases massively, the reserved metadata can run out.

The increase of the number of extents easily occurs on zoned filesystem
if BTRFS_MAX_EXTENT_SIZE > max_zone_append_size. And, it causes the
following warning on a small RAM environment with disabling metadata
over-commit (in the following patch).

[75721.498492] ------------[ cut here ]------------
[75721.505624] BTRFS: block rsv 1 returned -28
[75721.512230] WARNING: CPU: 24 PID: 2327559 at fs/btrfs/block-rsv.c:537 btrfs_use_block_rsv+0x560/0x760 [btrfs]
[75721.581854] CPU: 24 PID: 2327559 Comm: kworker/u64:10 Kdump: loaded Tainted: G        W         5.18.0-rc2-BTRFS-ZNS+ #109
[75721.597200] Hardware name: Supermicro Super Server/H12SSL-NT, BIOS 2.0 02/22/2021
[75721.607310] Workqueue: btrfs-endio-write btrfs_work_helper [btrfs]
[75721.616209] RIP: 0010:btrfs_use_block_rsv+0x560/0x760 [btrfs]
[75721.646649] RSP: 0018:ffffc9000fbdf3e0 EFLAGS: 00010286
[75721.654126] RAX: 0000000000000000 RBX: 0000000000004000 RCX: 0000000000000000
[75721.663524] RDX: 0000000000000004 RSI: 0000000000000008 RDI: fffff52001f7be6e
[75721.672921] RBP: ffffc9000fbdf420 R08: 0000000000000001 R09: ffff889f8d1fc6c7
[75721.682493] R10: ffffed13f1a3f8d8 R11: 0000000000000001 R12: ffff88980a3c0e28
[75721.692284] R13: ffff889b66590000 R14: ffff88980a3c0e40 R15: ffff88980a3c0e8a
[75721.701878] FS:  0000000000000000(0000) GS:ffff889f8d000000(0000) knlGS:0000000000000000
[75721.712601] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[75721.720726] CR2: 000055d12e05c018 CR3: 0000800193594000 CR4: 0000000000350ee0
[75721.730499] Call Trace:
[75721.735166]  <TASK>
[75721.739886]  btrfs_alloc_tree_block+0x1e1/0x1100 [btrfs]
[75721.747545]  ? btrfs_alloc_logged_file_extent+0x550/0x550 [btrfs]
[75721.756145]  ? btrfs_get_32+0xea/0x2d0 [btrfs]
[75721.762852]  ? btrfs_get_32+0xea/0x2d0 [btrfs]
[75721.769520]  ? push_leaf_left+0x420/0x620 [btrfs]
[75721.776431]  ? memcpy+0x4e/0x60
[75721.781931]  split_leaf+0x433/0x12d0 [btrfs]
[75721.788392]  ? btrfs_get_token_32+0x580/0x580 [btrfs]
[75721.795636]  ? push_for_double_split.isra.0+0x420/0x420 [btrfs]
[75721.803759]  ? leaf_space_used+0x15d/0x1a0 [btrfs]
[75721.811156]  btrfs_search_slot+0x1bc3/0x2790 [btrfs]
[75721.818300]  ? lock_downgrade+0x7c0/0x7c0
[75721.824411]  ? free_extent_buffer.part.0+0x107/0x200 [btrfs]
[75721.832456]  ? split_leaf+0x12d0/0x12d0 [btrfs]
[75721.839149]  ? free_extent_buffer.part.0+0x14f/0x200 [btrfs]
[75721.846945]  ? free_extent_buffer+0x13/0x20 [btrfs]
[75721.853960]  ? btrfs_release_path+0x4b/0x190 [btrfs]
[75721.861429]  btrfs_csum_file_blocks+0x85c/0x1500 [btrfs]
[75721.869313]  ? rcu_read_lock_sched_held+0x16/0x80
[75721.876085]  ? lock_release+0x552/0xf80
[75721.881957]  ? btrfs_del_csums+0x8c0/0x8c0 [btrfs]
[75721.888886]  ? __kasan_check_write+0x14/0x20
[75721.895152]  ? do_raw_read_unlock+0x44/0x80
[75721.901323]  ? _raw_write_lock_irq+0x60/0x80
[75721.907983]  ? btrfs_global_root+0xb9/0xe0 [btrfs]
[75721.915166]  ? btrfs_csum_root+0x12b/0x180 [btrfs]
[75721.921918]  ? btrfs_get_global_root+0x820/0x820 [btrfs]
[75721.929166]  ? _raw_write_unlock+0x23/0x40
[75721.935116]  ? unpin_extent_cache+0x1e3/0x390 [btrfs]
[75721.942041]  btrfs_finish_ordered_io.isra.0+0xa0c/0x1dc0 [btrfs]
[75721.949906]  ? try_to_wake_up+0x30/0x14a0
[75721.955700]  ? btrfs_unlink_subvol+0xda0/0xda0 [btrfs]
[75721.962661]  ? rcu_read_lock_sched_held+0x16/0x80
[75721.969111]  ? lock_acquire+0x41b/0x4c0
[75721.974982]  finish_ordered_fn+0x15/0x20 [btrfs]
[75721.981639]  btrfs_work_helper+0x1af/0xa80 [btrfs]
[75721.988184]  ? _raw_spin_unlock_irq+0x28/0x50
[75721.994643]  process_one_work+0x815/0x1460
[75722.000444]  ? pwq_dec_nr_in_flight+0x250/0x250
[75722.006643]  ? do_raw_spin_trylock+0xbb/0x190
[75722.013086]  worker_thread+0x59a/0xeb0
[75722.018511]  kthread+0x2ac/0x360
[75722.023428]  ? process_one_work+0x1460/0x1460
[75722.029431]  ? kthread_complete_and_exit+0x30/0x30
[75722.036044]  ret_from_fork+0x22/0x30
[75722.041255]  </TASK>
[75722.045047] irq event stamp: 0
[75722.049703] hardirqs last  enabled at (0): [<0000000000000000>] 0x0
[75722.057610] hardirqs last disabled at (0): [<ffffffff8118a94a>] copy_process+0x1c1a/0x66b0
[75722.067533] softirqs last  enabled at (0): [<ffffffff8118a989>] copy_process+0x1c59/0x66b0
[75722.077423] softirqs last disabled at (0): [<0000000000000000>] 0x0
[75722.085335] ---[ end trace 0000000000000000 ]---

To fix the estimation, we need to introduce fs_info->max_extent_size to
replace BTRFS_MAX_EXTENT_SIZE, which allow setting the different size for
regular vs zoned filesystem.

Set fs_info->max_extent_size to BTRFS_MAX_EXTENT_SIZE by default. On zoned
filesystem, it is set to fs_info->max_zone_append_size.

CC: stable@vger.kernel.org # 5.12+
Fixes: d8e3fb106f39 ("btrfs: zoned: use ZONE_APPEND write for zoned mode")
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
---
 fs/btrfs/ctree.h     | 6 ++++++
 fs/btrfs/disk-io.c   | 2 ++
 fs/btrfs/extent_io.c | 4 +++-
 fs/btrfs/inode.c     | 6 ++++--
 fs/btrfs/zoned.c     | 5 ++++-
 5 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 099c30477cf2..e751eb1b5514 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -999,6 +999,12 @@ struct btrfs_fs_info {
 	u32 csums_per_leaf;
 	u32 stripesize;
 
+	/*
+	 * Maximum size of an extent. BTRFS_MAX_EXTENT_SIZE on regular
+	 * filesystem, on zoned it depends on the device constraints.
+	 */
+	u64 max_extent_size;
+
 	/* Block groups and devices containing active swapfiles. */
 	spinlock_t swapfile_pins_lock;
 	struct rb_root swapfile_pins;
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index e65c3039caf1..247d7f9ced3b 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -3006,6 +3006,8 @@ void btrfs_init_fs_info(struct btrfs_fs_info *fs_info)
 	fs_info->sectorsize_bits = ilog2(4096);
 	fs_info->stripesize = 4096;
 
+	fs_info->max_extent_size = BTRFS_MAX_EXTENT_SIZE;
+
 	spin_lock_init(&fs_info->swapfile_pins_lock);
 	fs_info->swapfile_pins = RB_ROOT;
 
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index a90546b3107c..41862045b3de 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -1985,8 +1985,10 @@ noinline_for_stack bool find_lock_delalloc_range(struct inode *inode,
 				    struct page *locked_page, u64 *start,
 				    u64 *end)
 {
+	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
 	struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
-	u64 max_bytes = BTRFS_MAX_EXTENT_SIZE;
+	/* The sanity tests may not set a valid fs_info. */
+	u64 max_bytes = fs_info ? fs_info->max_extent_size : BTRFS_MAX_EXTENT_SIZE;
 	u64 delalloc_start;
 	u64 delalloc_end;
 	bool found;
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 20d0dea1d0c4..91417cdbf70d 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -2032,6 +2032,7 @@ int btrfs_run_delalloc_range(struct btrfs_inode *inode, struct page *locked_page
 void btrfs_split_delalloc_extent(struct inode *inode,
 				 struct extent_state *orig, u64 split)
 {
+	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
 	u64 size;
 
 	/* not delalloc, ignore it */
@@ -2039,7 +2040,7 @@ void btrfs_split_delalloc_extent(struct inode *inode,
 		return;
 
 	size = orig->end - orig->start + 1;
-	if (size > BTRFS_MAX_EXTENT_SIZE) {
+	if (size > fs_info->max_extent_size) {
 		u32 num_extents;
 		u64 new_size;
 
@@ -2068,6 +2069,7 @@ void btrfs_split_delalloc_extent(struct inode *inode,
 void btrfs_merge_delalloc_extent(struct inode *inode, struct extent_state *new,
 				 struct extent_state *other)
 {
+	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
 	u64 new_size, old_size;
 	u32 num_extents;
 
@@ -2081,7 +2083,7 @@ void btrfs_merge_delalloc_extent(struct inode *inode, struct extent_state *new,
 		new_size = other->end - new->start + 1;
 
 	/* we're not bigger than the max, unreserve the space and go */
-	if (new_size <= BTRFS_MAX_EXTENT_SIZE) {
+	if (new_size <= fs_info->max_extent_size) {
 		spin_lock(&BTRFS_I(inode)->lock);
 		btrfs_mod_outstanding_extents(BTRFS_I(inode), -1);
 		spin_unlock(&BTRFS_I(inode)->lock);
diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c
index bfbceb94c4e2..7a127d3c521f 100644
--- a/fs/btrfs/zoned.c
+++ b/fs/btrfs/zoned.c
@@ -670,8 +670,11 @@ int btrfs_check_zoned_mode(struct btrfs_fs_info *fs_info)
 	}
 
 	fs_info->zone_size = zone_size;
-	fs_info->max_zone_append_size = max_zone_append_size;
+	fs_info->max_zone_append_size = ALIGN_DOWN(max_zone_append_size,
+						   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;
 
 	/*
 	 * Check mount options here, because we might change fs_info->zoned
-- 
2.37.2

[PATCH STABLE 5.15 5/5] btrfs: convert count_max_extents() to use fs_info->max_extent_size

[Naohiro Aota]

commit 7d7672bc5d1038c745716c397d892d21e29de71c upstream

If count_max_extents() uses BTRFS_MAX_EXTENT_SIZE to calculate the number
of extents needed, btrfs release the metadata reservation too much on its
way to write out the data.

Now that BTRFS_MAX_EXTENT_SIZE is replaced with fs_info->max_extent_size,
convert count_max_extents() to use it instead, and fix the calculation of
the metadata reservation.

CC: stable@vger.kernel.org # 5.12+
Fixes: d8e3fb106f39 ("btrfs: zoned: use ZONE_APPEND write for zoned mode")
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
---
 fs/btrfs/ctree.h          | 21 +++++++++++++--------
 fs/btrfs/delalloc-space.c |  6 +++---
 fs/btrfs/inode.c          | 16 ++++++++--------
 3 files changed, 24 insertions(+), 19 deletions(-)

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index e751eb1b5514..1831135fef1a 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -105,14 +105,6 @@ struct btrfs_ref;
 #define BTRFS_STAT_CURR		0
 #define BTRFS_STAT_PREV		1
 
-/*
- * Count how many BTRFS_MAX_EXTENT_SIZE cover the @size
- */
-static inline u32 count_max_extents(u64 size)
-{
-	return div_u64(size + BTRFS_MAX_EXTENT_SIZE - 1, BTRFS_MAX_EXTENT_SIZE);
-}
-
 static inline unsigned long btrfs_chunk_item_size(int num_stripes)
 {
 	BUG_ON(num_stripes == 0);
@@ -3878,6 +3870,19 @@ static inline bool btrfs_is_zoned(const struct btrfs_fs_info *fs_info)
 	return fs_info->zoned != 0;
 }
 
+/*
+ * Count how many fs_info->max_extent_size cover the @size
+ */
+static inline u32 count_max_extents(struct btrfs_fs_info *fs_info, u64 size)
+{
+#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
+	if (!fs_info)
+		return div_u64(size + BTRFS_MAX_EXTENT_SIZE - 1, BTRFS_MAX_EXTENT_SIZE);
+#endif
+
+	return div_u64(size + fs_info->max_extent_size - 1, fs_info->max_extent_size);
+}
+
 static inline bool btrfs_is_data_reloc_root(const struct btrfs_root *root)
 {
 	return root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID;
diff --git a/fs/btrfs/delalloc-space.c b/fs/btrfs/delalloc-space.c
index 40c4d6ba3fb9..b934429c2435 100644
--- a/fs/btrfs/delalloc-space.c
+++ b/fs/btrfs/delalloc-space.c
@@ -273,7 +273,7 @@ static void calc_inode_reservations(struct btrfs_fs_info *fs_info,
 				    u64 num_bytes, u64 *meta_reserve,
 				    u64 *qgroup_reserve)
 {
-	u64 nr_extents = count_max_extents(num_bytes);
+	u64 nr_extents = count_max_extents(fs_info, num_bytes);
 	u64 csum_leaves = btrfs_csum_bytes_to_leaves(fs_info, num_bytes);
 	u64 inode_update = btrfs_calc_metadata_size(fs_info, 1);
 
@@ -347,7 +347,7 @@ int btrfs_delalloc_reserve_metadata(struct btrfs_inode *inode, u64 num_bytes)
 	 * needs to free the reservation we just made.
 	 */
 	spin_lock(&inode->lock);
-	nr_extents = count_max_extents(num_bytes);
+	nr_extents = count_max_extents(fs_info, num_bytes);
 	btrfs_mod_outstanding_extents(inode, nr_extents);
 	inode->csum_bytes += num_bytes;
 	btrfs_calculate_inode_block_rsv_size(fs_info, inode);
@@ -410,7 +410,7 @@ void btrfs_delalloc_release_extents(struct btrfs_inode *inode, u64 num_bytes)
 	unsigned num_extents;
 
 	spin_lock(&inode->lock);
-	num_extents = count_max_extents(num_bytes);
+	num_extents = count_max_extents(fs_info, num_bytes);
 	btrfs_mod_outstanding_extents(inode, -num_extents);
 	btrfs_calculate_inode_block_rsv_size(fs_info, inode);
 	spin_unlock(&inode->lock);
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 91417cdbf70d..ac6ba984973c 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -2049,10 +2049,10 @@ void btrfs_split_delalloc_extent(struct inode *inode,
 		 * applies here, just in reverse.
 		 */
 		new_size = orig->end - split + 1;
-		num_extents = count_max_extents(new_size);
+		num_extents = count_max_extents(fs_info, new_size);
 		new_size = split - orig->start;
-		num_extents += count_max_extents(new_size);
-		if (count_max_extents(size) >= num_extents)
+		num_extents += count_max_extents(fs_info, new_size);
+		if (count_max_extents(fs_info, size) >= num_extents)
 			return;
 	}
 
@@ -2109,10 +2109,10 @@ void btrfs_merge_delalloc_extent(struct inode *inode, struct extent_state *new,
 	 * this case.
 	 */
 	old_size = other->end - other->start + 1;
-	num_extents = count_max_extents(old_size);
+	num_extents = count_max_extents(fs_info, old_size);
 	old_size = new->end - new->start + 1;
-	num_extents += count_max_extents(old_size);
-	if (count_max_extents(new_size) >= num_extents)
+	num_extents += count_max_extents(fs_info, old_size);
+	if (count_max_extents(fs_info, new_size) >= num_extents)
 		return;
 
 	spin_lock(&BTRFS_I(inode)->lock);
@@ -2191,7 +2191,7 @@ void btrfs_set_delalloc_extent(struct inode *inode, struct extent_state *state,
 	if (!(state->state & EXTENT_DELALLOC) && (*bits & EXTENT_DELALLOC)) {
 		struct btrfs_root *root = BTRFS_I(inode)->root;
 		u64 len = state->end + 1 - state->start;
-		u32 num_extents = count_max_extents(len);
+		u32 num_extents = count_max_extents(fs_info, len);
 		bool do_list = !btrfs_is_free_space_inode(BTRFS_I(inode));
 
 		spin_lock(&BTRFS_I(inode)->lock);
@@ -2233,7 +2233,7 @@ void btrfs_clear_delalloc_extent(struct inode *vfs_inode,
 	struct btrfs_inode *inode = BTRFS_I(vfs_inode);
 	struct btrfs_fs_info *fs_info = btrfs_sb(vfs_inode->i_sb);
 	u64 len = state->end + 1 - state->start;
-	u32 num_extents = count_max_extents(len);
+	u32 num_extents = count_max_extents(fs_info, len);
 
 	if ((state->state & EXTENT_DEFRAG) && (*bits & EXTENT_DEFRAG)) {
 		spin_lock(&inode->lock);
-- 
2.37.2

Re: [PATCH STABLE 5.15 0/5] btrfs: zoned: backport max_extent_size fix

[Greg KH]

On Mon, Aug 22, 2022 at 03:06:59PM +0900, Naohiro Aota wrote:
> These patches are backport for the 5.15 branch.
> 
> This series backports fixes for expecting the number of on-going write
> extents on zoned mode.
> 
> It picks up patches 1 to 3 for the dependencies of patches 4 and 5.
> 
> Christoph Hellwig (1):
>   block: add a bdev_max_zone_append_sectors helper
> 
> Naohiro Aota (4):
>   block: add bdev_max_segments() helper
>   btrfs: zoned: revive max_zone_append_bytes
>   btrfs: replace BTRFS_MAX_EXTENT_SIZE with fs_info->max_extent_size
>   btrfs: convert count_max_extents() to use fs_info->max_extent_size
> 
>  drivers/nvme/target/zns.c |  3 +--
>  fs/btrfs/ctree.h          | 29 +++++++++++++++++++++--------
>  fs/btrfs/delalloc-space.c |  6 +++---
>  fs/btrfs/disk-io.c        |  2 ++
>  fs/btrfs/extent_io.c      |  4 +++-
>  fs/btrfs/inode.c          | 22 ++++++++++++----------
>  fs/btrfs/zoned.c          | 20 ++++++++++++++++++++
>  fs/btrfs/zoned.h          |  1 +
>  fs/zonefs/super.c         |  3 +--
>  include/linux/blkdev.h    | 11 +++++++++++
>  10 files changed, 75 insertions(+), 26 deletions(-)
> 
> -- 
> 2.37.2
> 

All now queued up, thanks.

greg k-h