diff options
Diffstat (limited to 'fs/btrfs/fs.c')
| -rw-r--r-- | fs/btrfs/fs.c | 48 |
1 files changed, 48 insertions, 0 deletions
diff --git a/fs/btrfs/fs.c b/fs/btrfs/fs.c index b2bb86f8d7cf..feb0a2faa837 100644 --- a/fs/btrfs/fs.c +++ b/fs/btrfs/fs.c @@ -55,6 +55,54 @@ size_t __attribute_const__ btrfs_get_num_csums(void) } /* + * We support the following block sizes for all systems: + * + * - 4K + * This is the most common block size. For PAGE SIZE > 4K cases the subpage + * mode is used. + * + * - PAGE_SIZE + * The straightforward block size to support. + * + * And extra support for the following block sizes based on the kernel config: + * + * - MIN_BLOCKSIZE + * This is either 4K (regular builds) or 2K (debug builds) + * This allows testing subpage routines on x86_64. + */ +bool __attribute_const__ btrfs_supported_blocksize(u32 blocksize) +{ + /* @blocksize should be validated first. */ + ASSERT(is_power_of_2(blocksize) && blocksize >= BTRFS_MIN_BLOCKSIZE && + blocksize <= BTRFS_MAX_BLOCKSIZE); + + if (blocksize == PAGE_SIZE || blocksize == SZ_4K || blocksize == BTRFS_MIN_BLOCKSIZE) + return true; +#ifdef CONFIG_BTRFS_EXPERIMENTAL + /* + * For bs > ps support it's done by specifying a minimal folio order + * for filemap, thus implying large data folios. + * For HIGHMEM systems, we can not always access the content of a (large) + * folio in one go, but go through them page by page. + * + * A lot of features don't implement a proper PAGE sized loop for large + * folios, this includes: + * + * - compression + * - verity + * - encoded write + * + * Considering HIGHMEM is such a pain to deal with and it's going + * to be deprecated eventually, just reject HIGHMEM && bs > ps cases. + */ + if (IS_ENABLED(CONFIG_HIGHMEM) && blocksize > PAGE_SIZE) + return false; + return true; +#endif + return false; +} + +/* * Start exclusive operation @type, return true on success. */ bool btrfs_exclop_start(struct btrfs_fs_info *fs_info, |