diff options
Diffstat (limited to 'fs/erofs/fscache.c')
| -rw-r--r-- | fs/erofs/fscache.c | 674 |
1 files changed, 674 insertions, 0 deletions
diff --git a/fs/erofs/fscache.c b/fs/erofs/fscache.c new file mode 100644 index 000000000000..fe05bc51f9f2 --- /dev/null +++ b/fs/erofs/fscache.c @@ -0,0 +1,674 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright (C) 2022, Alibaba Cloud + * Copyright (C) 2022, Bytedance Inc. All rights reserved. + */ +#include <linux/fscache.h> +#include "internal.h" + +static DEFINE_MUTEX(erofs_domain_list_lock); +static DEFINE_MUTEX(erofs_domain_cookies_lock); +static LIST_HEAD(erofs_domain_list); +static struct vfsmount *erofs_pseudo_mnt; + +static struct netfs_io_request *erofs_fscache_alloc_request(struct address_space *mapping, + loff_t start, size_t len) +{ + struct netfs_io_request *rreq; + + rreq = kzalloc(sizeof(struct netfs_io_request), GFP_KERNEL); + if (!rreq) + return ERR_PTR(-ENOMEM); + + rreq->start = start; + rreq->len = len; + rreq->mapping = mapping; + rreq->inode = mapping->host; + INIT_LIST_HEAD(&rreq->subrequests); + refcount_set(&rreq->ref, 1); + return rreq; +} + +static void erofs_fscache_put_request(struct netfs_io_request *rreq) +{ + if (!refcount_dec_and_test(&rreq->ref)) + return; + if (rreq->cache_resources.ops) + rreq->cache_resources.ops->end_operation(&rreq->cache_resources); + kfree(rreq); +} + +static void erofs_fscache_put_subrequest(struct netfs_io_subrequest *subreq) +{ + if (!refcount_dec_and_test(&subreq->ref)) + return; + erofs_fscache_put_request(subreq->rreq); + kfree(subreq); +} + +static void erofs_fscache_clear_subrequests(struct netfs_io_request *rreq) +{ + struct netfs_io_subrequest *subreq; + + while (!list_empty(&rreq->subrequests)) { + subreq = list_first_entry(&rreq->subrequests, + struct netfs_io_subrequest, rreq_link); + list_del(&subreq->rreq_link); + erofs_fscache_put_subrequest(subreq); + } +} + +static void erofs_fscache_rreq_unlock_folios(struct netfs_io_request *rreq) +{ + struct netfs_io_subrequest *subreq; + struct folio *folio; + unsigned int iopos = 0; + pgoff_t start_page = rreq->start / PAGE_SIZE; + pgoff_t last_page = ((rreq->start + rreq->len) / PAGE_SIZE) - 1; + bool subreq_failed = false; + + XA_STATE(xas, &rreq->mapping->i_pages, start_page); + + subreq = list_first_entry(&rreq->subrequests, + struct netfs_io_subrequest, rreq_link); + subreq_failed = (subreq->error < 0); + + rcu_read_lock(); + xas_for_each(&xas, folio, last_page) { + unsigned int pgpos = + (folio_index(folio) - start_page) * PAGE_SIZE; + unsigned int pgend = pgpos + folio_size(folio); + bool pg_failed = false; + + for (;;) { + if (!subreq) { + pg_failed = true; + break; + } + + pg_failed |= subreq_failed; + if (pgend < iopos + subreq->len) + break; + + iopos += subreq->len; + if (!list_is_last(&subreq->rreq_link, + &rreq->subrequests)) { + subreq = list_next_entry(subreq, rreq_link); + subreq_failed = (subreq->error < 0); + } else { + subreq = NULL; + subreq_failed = false; + } + if (pgend == iopos) + break; + } + + if (!pg_failed) + folio_mark_uptodate(folio); + + folio_unlock(folio); + } + rcu_read_unlock(); +} + +static void erofs_fscache_rreq_complete(struct netfs_io_request *rreq) +{ + erofs_fscache_rreq_unlock_folios(rreq); + erofs_fscache_clear_subrequests(rreq); + erofs_fscache_put_request(rreq); +} + +static void erofc_fscache_subreq_complete(void *priv, + ssize_t transferred_or_error, bool was_async) +{ + struct netfs_io_subrequest *subreq = priv; + struct netfs_io_request *rreq = subreq->rreq; + + if (IS_ERR_VALUE(transferred_or_error)) + subreq->error = transferred_or_error; + + if (atomic_dec_and_test(&rreq->nr_outstanding)) + erofs_fscache_rreq_complete(rreq); + + erofs_fscache_put_subrequest(subreq); +} + +/* + * Read data from fscache and fill the read data into page cache described by + * @rreq, which shall be both aligned with PAGE_SIZE. @pstart describes + * the start physical address in the cache file. + */ +static int erofs_fscache_read_folios_async(struct fscache_cookie *cookie, + struct netfs_io_request *rreq, loff_t pstart) +{ + enum netfs_io_source source; + struct super_block *sb = rreq->mapping->host->i_sb; + struct netfs_io_subrequest *subreq; + struct netfs_cache_resources *cres = &rreq->cache_resources; + struct iov_iter iter; + loff_t start = rreq->start; + size_t len = rreq->len; + size_t done = 0; + int ret; + + atomic_set(&rreq->nr_outstanding, 1); + + ret = fscache_begin_read_operation(cres, cookie); + if (ret) + goto out; + + while (done < len) { + subreq = kzalloc(sizeof(struct netfs_io_subrequest), + GFP_KERNEL); + if (subreq) { + INIT_LIST_HEAD(&subreq->rreq_link); + refcount_set(&subreq->ref, 2); + subreq->rreq = rreq; + refcount_inc(&rreq->ref); + } else { + ret = -ENOMEM; + goto out; + } + + subreq->start = pstart + done; + subreq->len = len - done; + subreq->flags = 1 << NETFS_SREQ_ONDEMAND; + + list_add_tail(&subreq->rreq_link, &rreq->subrequests); + + source = cres->ops->prepare_read(subreq, LLONG_MAX); + if (WARN_ON(subreq->len == 0)) + source = NETFS_INVALID_READ; + if (source != NETFS_READ_FROM_CACHE) { + erofs_err(sb, "failed to fscache prepare_read (source %d)", + source); + ret = -EIO; + subreq->error = ret; + erofs_fscache_put_subrequest(subreq); + goto out; + } + + atomic_inc(&rreq->nr_outstanding); + + iov_iter_xarray(&iter, READ, &rreq->mapping->i_pages, + start + done, subreq->len); + + ret = fscache_read(cres, subreq->start, &iter, + NETFS_READ_HOLE_FAIL, + erofc_fscache_subreq_complete, subreq); + if (ret == -EIOCBQUEUED) + ret = 0; + if (ret) { + erofs_err(sb, "failed to fscache_read (ret %d)", ret); + goto out; + } + + done += subreq->len; + } +out: + if (atomic_dec_and_test(&rreq->nr_outstanding)) + erofs_fscache_rreq_complete(rreq); + + return ret; +} + +static int erofs_fscache_meta_read_folio(struct file *data, struct folio *folio) +{ + int ret; + struct super_block *sb = folio_mapping(folio)->host->i_sb; + struct netfs_io_request *rreq; + struct erofs_map_dev mdev = { + .m_deviceid = 0, + .m_pa = folio_pos(folio), + }; + + ret = erofs_map_dev(sb, &mdev); + if (ret) + goto out; + + rreq = erofs_fscache_alloc_request(folio_mapping(folio), + folio_pos(folio), folio_size(folio)); + if (IS_ERR(rreq)) { + ret = PTR_ERR(rreq); + goto out; + } + + return erofs_fscache_read_folios_async(mdev.m_fscache->cookie, + rreq, mdev.m_pa); +out: + folio_unlock(folio); + return ret; +} + +/* + * Read into page cache in the range described by (@pos, @len). + * + * On return, the caller is responsible for page unlocking if the output @unlock + * is true, or the callee will take this responsibility through netfs_io_request + * interface. + * + * The return value is the number of bytes successfully handled, or negative + * error code on failure. The only exception is that, the length of the range + * instead of the error code is returned on failure after netfs_io_request is + * allocated, so that .readahead() could advance rac accordingly. + */ +static int erofs_fscache_data_read(struct address_space *mapping, + loff_t pos, size_t len, bool *unlock) +{ + struct inode *inode = mapping->host; + struct super_block *sb = inode->i_sb; + struct netfs_io_request *rreq; + struct erofs_map_blocks map; + struct erofs_map_dev mdev; + struct iov_iter iter; + size_t count; + int ret; + + *unlock = true; + + map.m_la = pos; + ret = erofs_map_blocks(inode, &map, EROFS_GET_BLOCKS_RAW); + if (ret) + return ret; + + if (map.m_flags & EROFS_MAP_META) { + struct erofs_buf buf = __EROFS_BUF_INITIALIZER; + erofs_blk_t blknr; + size_t offset, size; + void *src; + + /* For tail packing layout, the offset may be non-zero. */ + offset = erofs_blkoff(map.m_pa); + blknr = erofs_blknr(map.m_pa); + size = map.m_llen; + + src = erofs_read_metabuf(&buf, sb, blknr, EROFS_KMAP); + if (IS_ERR(src)) + return PTR_ERR(src); + + iov_iter_xarray(&iter, READ, &mapping->i_pages, pos, PAGE_SIZE); + if (copy_to_iter(src + offset, size, &iter) != size) + return -EFAULT; + iov_iter_zero(PAGE_SIZE - size, &iter); + erofs_put_metabuf(&buf); + return PAGE_SIZE; + } + + count = min_t(size_t, map.m_llen - (pos - map.m_la), len); + DBG_BUGON(!count || count % PAGE_SIZE); + + if (!(map.m_flags & EROFS_MAP_MAPPED)) { + iov_iter_xarray(&iter, READ, &mapping->i_pages, pos, count); + iov_iter_zero(count, &iter); + return count; + } + + mdev = (struct erofs_map_dev) { + .m_deviceid = map.m_deviceid, + .m_pa = map.m_pa, + }; + ret = erofs_map_dev(sb, &mdev); + if (ret) + return ret; + + rreq = erofs_fscache_alloc_request(mapping, pos, count); + if (IS_ERR(rreq)) + return PTR_ERR(rreq); + + *unlock = false; + erofs_fscache_read_folios_async(mdev.m_fscache->cookie, + rreq, mdev.m_pa + (pos - map.m_la)); + return count; +} + +static int erofs_fscache_read_folio(struct file *file, struct folio *folio) +{ + bool unlock; + int ret; + + DBG_BUGON(folio_size(folio) != EROFS_BLKSIZ); + + ret = erofs_fscache_data_read(folio_mapping(folio), folio_pos(folio), + folio_size(folio), &unlock); + if (unlock) { + if (ret > 0) + folio_mark_uptodate(folio); + folio_unlock(folio); + } + return ret < 0 ? ret : 0; +} + +static void erofs_fscache_readahead(struct readahead_control *rac) +{ + struct folio *folio; + size_t len, done = 0; + loff_t start, pos; + bool unlock; + int ret, size; + + if (!readahead_count(rac)) + return; + + start = readahead_pos(rac); + len = readahead_length(rac); + + do { + pos = start + done; + ret = erofs_fscache_data_read(rac->mapping, pos, + len - done, &unlock); + if (ret <= 0) + return; + + size = ret; + while (size) { + folio = readahead_folio(rac); + size -= folio_size(folio); + if (unlock) { + folio_mark_uptodate(folio); + folio_unlock(folio); + } + } + } while ((done += ret) < len); +} + +static const struct address_space_operations erofs_fscache_meta_aops = { + .read_folio = erofs_fscache_meta_read_folio, +}; + +const struct address_space_operations erofs_fscache_access_aops = { + .read_folio = erofs_fscache_read_folio, + .readahead = erofs_fscache_readahead, +}; + +static void erofs_fscache_domain_put(struct erofs_domain *domain) +{ + if (!domain) + return; + mutex_lock(&erofs_domain_list_lock); + if (refcount_dec_and_test(&domain->ref)) { + list_del(&domain->list); + if (list_empty(&erofs_domain_list)) { + kern_unmount(erofs_pseudo_mnt); + erofs_pseudo_mnt = NULL; + } + mutex_unlock(&erofs_domain_list_lock); + fscache_relinquish_volume(domain->volume, NULL, false); + kfree(domain->domain_id); + kfree(domain); + return; + } + mutex_unlock(&erofs_domain_list_lock); +} + +static int erofs_fscache_register_volume(struct super_block *sb) +{ + struct erofs_sb_info *sbi = EROFS_SB(sb); + char *domain_id = sbi->opt.domain_id; + struct fscache_volume *volume; + char *name; + int ret = 0; + + name = kasprintf(GFP_KERNEL, "erofs,%s", + domain_id ? domain_id : sbi->opt.fsid); + if (!name) + return -ENOMEM; + + volume = fscache_acquire_volume(name, NULL, NULL, 0); + if (IS_ERR_OR_NULL(volume)) { + erofs_err(sb, "failed to register volume for %s", name); + ret = volume ? PTR_ERR(volume) : -EOPNOTSUPP; + volume = NULL; + } + + sbi->volume = volume; + kfree(name); + return ret; +} + +static int erofs_fscache_init_domain(struct super_block *sb) +{ + int err; + struct erofs_domain *domain; + struct erofs_sb_info *sbi = EROFS_SB(sb); + + domain = kzalloc(sizeof(struct erofs_domain), GFP_KERNEL); + if (!domain) + return -ENOMEM; + + domain->domain_id = kstrdup(sbi->opt.domain_id, GFP_KERNEL); + if (!domain->domain_id) { + kfree(domain); + return -ENOMEM; + } + + err = erofs_fscache_register_volume(sb); + if (err) + goto out; + + if (!erofs_pseudo_mnt) { + erofs_pseudo_mnt = kern_mount(&erofs_fs_type); + if (IS_ERR(erofs_pseudo_mnt)) { + err = PTR_ERR(erofs_pseudo_mnt); + goto out; + } + } + + domain->volume = sbi->volume; + refcount_set(&domain->ref, 1); + list_add(&domain->list, &erofs_domain_list); + sbi->domain = domain; + return 0; +out: + kfree(domain->domain_id); + kfree(domain); + return err; +} + +static int erofs_fscache_register_domain(struct super_block *sb) +{ + int err; + struct erofs_domain *domain; + struct erofs_sb_info *sbi = EROFS_SB(sb); + + mutex_lock(&erofs_domain_list_lock); + list_for_each_entry(domain, &erofs_domain_list, list) { + if (!strcmp(domain->domain_id, sbi->opt.domain_id)) { + sbi->domain = domain; + sbi->volume = domain->volume; + refcount_inc(&domain->ref); + mutex_unlock(&erofs_domain_list_lock); + return 0; + } + } + err = erofs_fscache_init_domain(sb); + mutex_unlock(&erofs_domain_list_lock); + return err; +} + +static +struct erofs_fscache *erofs_fscache_acquire_cookie(struct super_block *sb, + char *name, bool need_inode) +{ + struct fscache_volume *volume = EROFS_SB(sb)->volume; + struct erofs_fscache *ctx; + struct fscache_cookie *cookie; + int ret; + + ctx = kzalloc(sizeof(*ctx), GFP_KERNEL); + if (!ctx) + return ERR_PTR(-ENOMEM); + + cookie = fscache_acquire_cookie(volume, FSCACHE_ADV_WANT_CACHE_SIZE, + name, strlen(name), NULL, 0, 0); + if (!cookie) { + erofs_err(sb, "failed to get cookie for %s", name); + ret = -EINVAL; + goto err; + } + + fscache_use_cookie(cookie, false); + ctx->cookie = cookie; + + if (need_inode) { + struct inode *const inode = new_inode(sb); + + if (!inode) { + erofs_err(sb, "failed to get anon inode for %s", name); + ret = -ENOMEM; + goto err_cookie; + } + + set_nlink(inode, 1); + inode->i_size = OFFSET_MAX; + inode->i_mapping->a_ops = &erofs_fscache_meta_aops; + mapping_set_gfp_mask(inode->i_mapping, GFP_NOFS); + + ctx->inode = inode; + } + + return ctx; + +err_cookie: + fscache_unuse_cookie(ctx->cookie, NULL, NULL); + fscache_relinquish_cookie(ctx->cookie, false); +err: + kfree(ctx); + return ERR_PTR(ret); +} + +static void erofs_fscache_relinquish_cookie(struct erofs_fscache *ctx) +{ + fscache_unuse_cookie(ctx->cookie, NULL, NULL); + fscache_relinquish_cookie(ctx->cookie, false); + iput(ctx->inode); + kfree(ctx->name); + kfree(ctx); +} + +static +struct erofs_fscache *erofs_fscache_domain_init_cookie(struct super_block *sb, + char *name, bool need_inode) +{ + int err; + struct inode *inode; + struct erofs_fscache *ctx; + struct erofs_domain *domain = EROFS_SB(sb)->domain; + + ctx = erofs_fscache_acquire_cookie(sb, name, need_inode); + if (IS_ERR(ctx)) + return ctx; + + ctx->name = kstrdup(name, GFP_KERNEL); + if (!ctx->name) { + err = -ENOMEM; + goto out; + } + + inode = new_inode(erofs_pseudo_mnt->mnt_sb); + if (!inode) { + err = -ENOMEM; + goto out; + } + + ctx->domain = domain; + ctx->anon_inode = inode; + inode->i_private = ctx; + refcount_inc(&domain->ref); + return ctx; +out: + erofs_fscache_relinquish_cookie(ctx); + return ERR_PTR(err); +} + +static +struct erofs_fscache *erofs_domain_register_cookie(struct super_block *sb, + char *name, bool need_inode) +{ + struct inode *inode; + struct erofs_fscache *ctx; + struct erofs_domain *domain = EROFS_SB(sb)->domain; + struct super_block *psb = erofs_pseudo_mnt->mnt_sb; + + mutex_lock(&erofs_domain_cookies_lock); + spin_lock(&psb->s_inode_list_lock); + list_for_each_entry(inode, &psb->s_inodes, i_sb_list) { + ctx = inode->i_private; + if (!ctx || ctx->domain != domain || strcmp(ctx->name, name)) + continue; + igrab(inode); + spin_unlock(&psb->s_inode_list_lock); + mutex_unlock(&erofs_domain_cookies_lock); + return ctx; + } + spin_unlock(&psb->s_inode_list_lock); + ctx = erofs_fscache_domain_init_cookie(sb, name, need_inode); + mutex_unlock(&erofs_domain_cookies_lock); + return ctx; +} + +struct erofs_fscache *erofs_fscache_register_cookie(struct super_block *sb, + char *name, bool need_inode) +{ + if (EROFS_SB(sb)->opt.domain_id) + return erofs_domain_register_cookie(sb, name, need_inode); + return erofs_fscache_acquire_cookie(sb, name, need_inode); +} + +void erofs_fscache_unregister_cookie(struct erofs_fscache *ctx) +{ + bool drop; + struct erofs_domain *domain; + + if (!ctx) + return; + domain = ctx->domain; + if (domain) { + mutex_lock(&erofs_domain_cookies_lock); + drop = atomic_read(&ctx->anon_inode->i_count) == 1; + iput(ctx->anon_inode); + mutex_unlock(&erofs_domain_cookies_lock); + if (!drop) + return; + } + + erofs_fscache_relinquish_cookie(ctx); + erofs_fscache_domain_put(domain); +} + +int erofs_fscache_register_fs(struct super_block *sb) +{ + int ret; + struct erofs_sb_info *sbi = EROFS_SB(sb); + struct erofs_fscache *fscache; + + if (sbi->opt.domain_id) + ret = erofs_fscache_register_domain(sb); + else + ret = erofs_fscache_register_volume(sb); + if (ret) + return ret; + + /* acquired domain/volume will be relinquished in kill_sb() on error */ + fscache = erofs_fscache_register_cookie(sb, sbi->opt.fsid, true); + if (IS_ERR(fscache)) + return PTR_ERR(fscache); + + sbi->s_fscache = fscache; + return 0; +} + +void erofs_fscache_unregister_fs(struct super_block *sb) +{ + struct erofs_sb_info *sbi = EROFS_SB(sb); + + erofs_fscache_unregister_cookie(sbi->s_fscache); + + if (sbi->domain) + erofs_fscache_domain_put(sbi->domain); + else + fscache_relinquish_volume(sbi->volume, NULL, false); + + sbi->s_fscache = NULL; + sbi->volume = NULL; + sbi->domain = NULL; +} |