On Tue, May 12, 2026 at 07:35:25AM +0200, Christoph Hellwig wrote:
> Only the file operation method knows what block device we'll swap
> to. So move down setting sis->bdev and the special blockdev flag
> into ->swap_activate.
>
> Signed-off-by: Christoph Hellwig <[email protected]>
> ---
> block/fops.c | 9 ++++++++-
> fs/btrfs/inode.c | 7 ++++---
> fs/f2fs/data.c | 3 ++-
> fs/iomap/swapfile.c | 7 ++-----
> fs/nfs/file.c | 2 +-
> fs/smb/client/file.c | 2 +-
> fs/xfs/xfs_file.c | 6 ------
> include/linux/swap.h | 4 ++--
> mm/page_io.c | 3 +--
> mm/swapfile.c | 38 ++++++++++++--------------------------
> 10 files changed, 33 insertions(+), 48 deletions(-)
>
> diff --git a/block/fops.c b/block/fops.c
> index 067e46299666..da09ce3f072f 100644
> --- a/block/fops.c
> +++ b/block/fops.c
> @@ -951,9 +951,16 @@ static int blkdev_mmap_prepare(struct vm_area_desc *desc)
>
> static int blkdev_swap_activate(struct file *file, struct swap_info_struct
> *sis)
> {
> + struct block_device *bdev = I_BDEV(file->f_mapping->host);
> loff_t isize = i_size_read(bdev_file_inode(file));
>
> - return add_swap_extent(sis, div_u64(isize, PAGE_SIZE), 0);
> + /*
> + * The swap code performs arbitrary overwrites, which are not supported
> + * on zones with sequential write constraints.
> + */
> + if (bdev_is_zoned(bdev))
> + return -EINVAL;
> + return add_swap_extent(sis, div_u64(isize, PAGE_SIZE), bdev, 0);
> }
>
> const struct file_operations def_blk_fops = {
> diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
> index ee0a7947706a..84003c520530 100644
> --- a/fs/btrfs/inode.c
> +++ b/fs/btrfs/inode.c
> @@ -10201,6 +10201,7 @@ static void btrfs_free_swapfile_pins(struct inode
> *inode)
> }
>
> struct btrfs_swap_info {
> + struct btrfs_device *device;
> u64 start;
> u64 block_start;
> u64 block_len;
> @@ -10214,7 +10215,8 @@ static int btrfs_add_swap_extent(struct
> swap_info_struct *sis,
> first_ppage = PAGE_ALIGN(bsi->block_start) >> PAGE_SHIFT;
> next_ppage = PAGE_ALIGN_DOWN(bsi->block_start + bsi->block_len) >>
> PAGE_SHIFT;
>
> - return add_swap_extent(sis, next_ppage - first_ppage, first_ppage);
> + return add_swap_extent(sis, next_ppage - first_ppage, bsi->device->bdev,
> + first_ppage);
> }
>
> void btrfs_swap_deactivate(struct file *file)
> @@ -10503,6 +10505,7 @@ int btrfs_swap_activate(struct file *file, struct
> swap_info_struct *sis)
> bsi.start = key.offset;
> bsi.block_start = physical_block_start;
> bsi.block_len = len;
> + bsi.device = device;
> }
>
> if (fatal_signal_pending(current)) {
> @@ -10533,8 +10536,6 @@ int btrfs_swap_activate(struct file *file, struct
> swap_info_struct *sis)
> up_write(&BTRFS_I(inode)->i_mmap_lock);
> btrfs_free_backref_share_ctx(backref_ctx);
> btrfs_free_path(path);
> - if (!ret && device)
> - sis->bdev = device->bdev;
> return ret;
> }
> #endif
> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> index 8bcf630df557..8d116ff517c9 100644
> --- a/fs/f2fs/data.c
> +++ b/fs/f2fs/data.c
> @@ -4326,7 +4326,8 @@ static int check_swap_activate(struct swap_info_struct
> *sis,
> /*
> * We found a PAGE_SIZE-length, PAGE_SIZE-aligned run of blocks
> */
> - ret = add_swap_extent(sis, nr_pblocks, pblock);
> + ret = add_swap_extent(sis, nr_pblocks, inode->i_sb->s_bdev,
> + pblock);
> if (ret < 0)
> goto out;
> cur_lblock += nr_pblocks;
> diff --git a/fs/iomap/swapfile.c b/fs/iomap/swapfile.c
> index a4e0ca462cc4..862b4c02a8bd 100644
> --- a/fs/iomap/swapfile.c
> +++ b/fs/iomap/swapfile.c
> @@ -50,10 +50,6 @@ static int iomap_swapfile_iter(struct iomap_iter *iter,
> struct file *file,
> if (iomap->flags & IOMAP_F_SHARED)
> return iomap_swapfile_fail(file, "has shared extents");
>
> - /* Only one bdev per swap file. */
> - if (iomap->bdev != sis->bdev)
> - return iomap_swapfile_fail(file, "outside the main device");
> -
> /*
> * Round the start up and the end down so that the physical extent
> * aligns to a page boundary.
> @@ -61,7 +57,8 @@ static int iomap_swapfile_iter(struct iomap_iter *iter,
> struct file *file,
> first_ppage = ALIGN(iomap->addr, PAGE_SIZE) >> PAGE_SHIFT;
> next_ppage = ALIGN_DOWN(iomap->addr + iomap->length, PAGE_SIZE) >>
> PAGE_SHIFT;
> - error = add_swap_extent(sis, next_ppage - first_ppage, first_ppage);
> + error = add_swap_extent(sis, next_ppage - first_ppage, iomap->bdev,
> + first_ppage);
> if (error)
> return error;
> return iomap_iter_advance_full(iter);
> diff --git a/fs/nfs/file.c b/fs/nfs/file.c
> index 2bc55d9d71e1..10ab2a923835 100644
> --- a/fs/nfs/file.c
> +++ b/fs/nfs/file.c
> @@ -588,7 +588,7 @@ int nfs_swap_activate(struct file *file, struct
> swap_info_struct *sis)
> ret = rpc_clnt_swap_activate(clnt);
> if (ret)
> return ret;
> - ret = add_swap_extent(sis, sis->max, 0);
> + ret = add_swap_extent(sis, sis->max, NULL, 0);
> if (ret < 0) {
> rpc_clnt_swap_deactivate(clnt);
> return ret;
> diff --git a/fs/smb/client/file.c b/fs/smb/client/file.c
> index 84459f87907e..e1bbc65ce7f3 100644
> --- a/fs/smb/client/file.c
> +++ b/fs/smb/client/file.c
> @@ -3327,7 +3327,7 @@ int cifs_swap_activate(struct file *swap_file, struct
> swap_info_struct *sis)
> */
>
> sis->flags |= SWP_FS_OPS;
> - return add_swap_extent(sis, sis->max, 0);
> + return add_swap_extent(sis, sis->max, NULL, 0);
> }
>
> void cifs_swap_deactivate(struct file *file)
> diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
> index 41f7e19bd31f..74128ebf7161 100644
> --- a/fs/xfs/xfs_file.c
> +++ b/fs/xfs/xfs_file.c
> @@ -2116,12 +2116,6 @@ xfs_file_swap_activate(
> */
> xfs_inodegc_flush(ip->i_mount);
>
> - /*
> - * Direct the swap code to the correct block device when this file
> - * sits on the RT device.
> - */
> - sis->bdev = xfs_inode_buftarg(ip)->bt_bdev;
> -
> return iomap_swap_activate(file, sis, &xfs_read_iomap_ops);
> }
>
> diff --git a/include/linux/swap.h b/include/linux/swap.h
> index 657779485ae4..b1cbb67ddd8e 100644
> --- a/include/linux/swap.h
> +++ b/include/linux/swap.h
> @@ -404,7 +404,7 @@ extern void __meminit kswapd_stop(int nid);
> #ifdef CONFIG_SWAP
>
> int add_swap_extent(struct swap_info_struct *sis, unsigned long nr_pages,
> - sector_t start_block);
> + struct block_device *bdev, sector_t start_block);
> int generic_swap_activate(struct file *swap_file, struct swap_info_struct
> *sis);
>
> static inline unsigned long total_swapcache_pages(void)
> @@ -528,7 +528,7 @@ static inline bool folio_free_swap(struct folio *folio)
>
> static inline int add_swap_extent(struct swap_info_struct *sis,
> unsigned long start_page, unsigned long nr_pages,
> - sector_t start_block)
> + struct block_device *bdev, sector_t start_block)
> {
> return -EINVAL;
> }
> diff --git a/mm/page_io.c b/mm/page_io.c
> index 3e1c12649448..2ab8994ed1c2 100644
> --- a/mm/page_io.c
> +++ b/mm/page_io.c
> @@ -132,7 +132,7 @@ int generic_swap_activate(struct file *swap_file, struct
> swap_info_struct *sis)
> /*
> * We found a PAGE_SIZE-length, PAGE_SIZE-aligned run of blocks
> */
> - ret = add_swap_extent(sis, 1,
> + ret = add_swap_extent(sis, 1, inode->i_sb->s_bdev,
> first_block >> (PAGE_SHIFT - blkbits));
> if (ret < 0)
> return ret;
> @@ -141,7 +141,6 @@ int generic_swap_activate(struct file *swap_file, struct
> swap_info_struct *sis)
> continue;
> }
> return 0;
> -
> bad_bmap:
> pr_err("swapon: swapfile has holes\n");
> return -EINVAL;
> diff --git a/mm/swapfile.c b/mm/swapfile.c
> index fbf11c8c5c69..2c9d2af736c4 100644
> --- a/mm/swapfile.c
> +++ b/mm/swapfile.c
> @@ -2707,7 +2707,7 @@ static void destroy_swap_extents(struct
> swap_info_struct *sis,
> */
> int
> add_swap_extent(struct swap_info_struct *sis, unsigned long nr_pages,
> - sector_t start_block)
> + struct block_device *bdev, sector_t start_block)
> {
> struct rb_node **link = &sis->swap_extent_root.rb_node, *parent = NULL;
> struct swap_extent *se;
> @@ -2718,6 +2718,12 @@ add_swap_extent(struct swap_info_struct *sis, unsigned
> long nr_pages,
> return 0;
> nr_pages = min(nr_pages, sis->max - sis->pages);
>
> + /* Only one bdev per swap file for now. */
> + if (!sis->bdev)
> + sis->bdev = bdev;
> + else if (bdev != sis->bdev)
> + return -EINVAL;
Should this return error if the bdev is zoned? AFAICT XFS and zonefs
already guard against this, but other fses might be more naïve.
--D
> +
> /*
> * place the new node at the right most since the
> * function is called in ascending page order.
> @@ -2793,6 +2799,8 @@ static int setup_swap_extents(struct swap_info_struct
> *sis,
> sis->flags |= SWP_ACTIVATED;
> if (sis->flags & SWP_FS_OPS)
> error = sio_pool_init();
> + else if (WARN_ON_ONCE(!sis->bdev))
> + error = -EINVAL;
> if (error)
> destroy_swap_extents(sis, swap_file);
> return error;
> @@ -3224,26 +3232,6 @@ static struct swap_info_struct *alloc_swap_info(void)
> return p;
> }
>
> -static int claim_swapfile(struct swap_info_struct *si, struct inode *inode)
> -{
> - if (S_ISBLK(inode->i_mode)) {
> - si->bdev = I_BDEV(inode);
> - /*
> - * Zoned block devices contain zones that have a sequential
> - * write only restriction. Hence zoned block devices are not
> - * suitable for swapping. Disallow them here.
> - */
> - if (bdev_is_zoned(si->bdev))
> - return -EINVAL;
> - si->flags |= SWP_BLKDEV;
> - } else if (S_ISREG(inode->i_mode)) {
> - si->bdev = inode->i_sb->s_bdev;
> - }
> -
> - return 0;
> -}
> -
> -
> /*
> * Find out how many pages are allowed for a single swap device. There
> * are two limiting factors:
> @@ -3500,16 +3488,14 @@ SYSCALL_DEFINE2(swapon, const char __user *,
> specialfile, int, swap_flags)
> dentry = swap_file->f_path.dentry;
> inode = mapping->host;
>
> - error = claim_swapfile(si, inode);
> - if (unlikely(error))
> - goto bad_swap;
> -
> inode_lock(inode);
> if (d_unlinked(dentry) || cant_mount(dentry)) {
> error = -ENOENT;
> goto bad_swap_unlock_inode;
> }
> - if (!S_ISBLK(inode->i_mode) && !S_ISREG(inode->i_mode)) {
> + if (S_ISBLK(inode->i_mode)) {
> + si->flags |= SWP_BLKDEV;
> + } else if (!S_ISREG(inode->i_mode)) {
> error = -EINVAL;
> goto bad_swap_unlock_inode;
> }
> --
> 2.53.0
>
>
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