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Mon, 9 Dec 2019 06:55:01 +0000 (GMT) From: Namjae Jeon To: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org Cc: gregkh@linuxfoundation.org, valdis.kletnieks@vt.edu, hch@lst.de, sj1557.seo@samsung.com, Namjae Jeon Subject: [PATCH v6 08/13] exfat: add exfat cache Date: Mon, 9 Dec 2019 01:51:43 -0500 Message-Id: <20191209065149.2230-9-namjae.jeon@samsung.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20191209065149.2230-1-namjae.jeon@samsung.com> X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFnrOKsWRmVeSWpSXmKPExsWy7bCmnu6x929jDbZe57doXryezWLl6qNM Fnv2nmSxuLxrDpvFj+n1Flv+HWG1uPT+A4sDu8f+uWvYPXbfbGDz6NuyitHj8yY5j0Pb37AF sEbl2GSkJqakFimk5iXnp2TmpdsqeQfHO8ebmhkY6hpaWpgrKeQl5qbaKrn4BOi6ZeYAXaGk UJaYUwoUCkgsLlbSt7Mpyi8tSVXIyC8usVVKLUjJKTA0KNArTswtLs1L10vOz7UyNDAwMgWq TMjJWLEuuaDHraLp2yymBsaNFl2MnBwSAiYSb25cZ+ti5OIQEtjBKNFxaAIzhPOJUeJS1xsW COcbo8T5GXNZYFqu3X7NBJHYyygx+c5qFriWpWs/AA3j4GAT0Jb4s0UUpEFEwF5i8+wDYDXM Ai2MEgtO/2AGqREWMJA4v1sPpIZFQFVib/9LdhCbV8Ba4ty6g2wQy+QlVm84wAxicwrYSLzp OQi2WEJgDpvE498ToYpcJI42bYKyhSVeHd/CDmFLSXx+txfsHgmBaomP+5khwh2MEi++20LY xhI3129gBSlhFtCUWL9LHyKsKLHz91xGEJtZgE/i3dceVogpvBIdbUIQJaoSfZcOM0HY0hJd 7R+glnpI7Pndzg4JkX5GiTX/LzNPYJSbhbBhASPjKkax1ILi3PTUYsMCY+T42sQITmRa5jsY N5zzOcQowMGoxMOrYPU2Vog1say4MvcQowQHs5II75KJr2KFeFMSK6tSi/Lji0pzUosPMZoC A3Iis5Rocj4wyeaVxBuaGhkbG1uYmJmbmRorifNy/LgYKySQnliSmp2aWpBaBNPHxMEp1cBY PLNbNrvNfvm3pgaBr+sbxa5H8i4rcCz6eadnxoU75zcZhTCv2+xwKX7J7IcpqvoLijxKw3Yw VniUeLCsaW361tD24rGrSNKaldvO+k0teu2S4LRJXYOv2rsxpXpr971Fa5ndBG8dmLX8UJMN n+rfez1eem88k19+zPIsm8/2v0nFV+fPg+1KLMUZiYZazEXFiQAxTR7NegMAAA== X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFprPLMWRmVeSWpSXmKPExsWy7bCSnO7R929jDZZN1LFoXryezWLl6qNM Fnv2nmSxuLxrDpvFj+n1Flv+HWG1uPT+A4sDu8f+uWvYPXbfbGDz6NuyitHj8yY5j0Pb37AF sEZx2aSk5mSWpRbp2yVwZaxYl1zQ41bR9G0WUwPjRosuRk4OCQETiWu3XzN1MXJxCAnsZpRY 1LCWGSIhLXHsxBkgmwPIFpY4fLgYJCwk8IFR4uXnbJAwm4C2xJ8toiBhEQFHid5dh1lAxjAL dDFKPGr6BtYqLGAgcX63HkgNi4CqxN7+l+wgNq+AtcS5dQfZIDbJS6zecABsK6eAjcSbnoNM EKusJa6+XMo4gZFvASPDKkbJ1ILi3PTcYsMCw7zUcr3ixNzi0rx0veT83E2M4GDT0tzBeHlJ /CFGAQ5GJR7eCpu3sUKsiWXFlbmHGCU4mJVEeJdMfBUrxJuSWFmVWpQfX1Sak1p8iFGag0VJ nPdp3rFIIYH0xJLU7NTUgtQimCwTB6dUA2Oni9w+H/5P1laxLwLifSvvvBc/XJupvadIydZ1 uuFju7XNro+fKXx7uai4uJZP7OvnZ99TbzkdE6yf+r/NdsKD+j+8JqI56/0jd1eq+CkYhpfG 8/LaLX0kGBla3tRwWdNNc2f/s+Bi3e19r+8Kr/y8O3P3i0CFZo76f1NfPOhaPL856vvtR0os xRmJhlrMRcWJAKm30rMyAgAA X-CMS-MailID: 20191209065501epcas1p44767c16feecd953fd5def1aaecb09313 X-Msg-Generator: CA Content-Type: text/plain; charset="utf-8" X-Sendblock-Type: SVC_REQ_APPROVE CMS-TYPE: 101P DLP-Filter: Pass X-CFilter-Loop: Reflected X-CMS-RootMailID: 20191209065501epcas1p44767c16feecd953fd5def1aaecb09313 References: <20191209065149.2230-1-namjae.jeon@samsung.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This adds the implementation of exfat cache. Signed-off-by: Namjae Jeon Signed-off-by: Sungjong Seo --- fs/exfat/cache.c | 325 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 325 insertions(+) create mode 100644 fs/exfat/cache.c diff --git a/fs/exfat/cache.c b/fs/exfat/cache.c new file mode 100644 index 000000000000..74f9a44471d5 --- /dev/null +++ b/fs/exfat/cache.c @@ -0,0 +1,325 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * linux/fs/fat/cache.c + * + * Written 1992,1993 by Werner Almesberger + * + * Mar 1999. AV. Changed cache, so that it uses the starting cluster instead + * of inode number. + * May 1999. AV. Fixed the bogosity with FAT32 (read "FAT28"). Fscking lusers. + * Copyright (C) 2012-2013 Samsung Electronics Co., Ltd. + */ + +#include +#include +#include + +#include "exfat_raw.h" +#include "exfat_fs.h" + +#define EXFAT_CACHE_VALID 0 +#define EXFAT_MAX_CACHE 16 + +struct exfat_cache { + struct list_head cache_list; + unsigned int nr_contig; /* number of contiguous clusters */ + unsigned int fcluster; /* cluster number in the file. */ + unsigned int dcluster; /* cluster number on disk. */ +}; + +struct exfat_cache_id { + unsigned int id; + unsigned int nr_contig; + unsigned int fcluster; + unsigned int dcluster; +}; + +static struct kmem_cache *exfat_cachep; + +static void exfat_cache_init_once(void *c) +{ + struct exfat_cache *cache = (struct exfat_cache *)c; + + INIT_LIST_HEAD(&cache->cache_list); +} + +int exfat_cache_init(void) +{ + exfat_cachep = kmem_cache_create("exfat_cache", + sizeof(struct exfat_cache), + 0, SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD, + exfat_cache_init_once); + if (!exfat_cachep) + return -ENOMEM; + return 0; +} + +void exfat_cache_shutdown(void) +{ + if (!exfat_cachep) + return; + kmem_cache_destroy(exfat_cachep); +} + +void exfat_cache_init_inode(struct inode *inode) +{ + struct exfat_inode_info *ei = EXFAT_I(inode); + + spin_lock_init(&ei->cache_lru_lock); + ei->nr_caches = 0; + ei->cache_valid_id = EXFAT_CACHE_VALID + 1; + INIT_LIST_HEAD(&ei->cache_lru); +} + +static inline struct exfat_cache *exfat_cache_alloc(void) +{ + return kmem_cache_alloc(exfat_cachep, GFP_NOFS); +} + +static inline void exfat_cache_free(struct exfat_cache *cache) +{ + WARN_ON(!list_empty(&cache->cache_list)); + kmem_cache_free(exfat_cachep, cache); +} + +static inline void exfat_cache_update_lru(struct inode *inode, + struct exfat_cache *cache) +{ + struct exfat_inode_info *ei = EXFAT_I(inode); + + if (ei->cache_lru.next != &cache->cache_list) + list_move(&cache->cache_list, &ei->cache_lru); +} + +static unsigned int exfat_cache_lookup(struct inode *inode, + unsigned int fclus, struct exfat_cache_id *cid, + unsigned int *cached_fclus, unsigned int *cached_dclus) +{ + struct exfat_inode_info *ei = EXFAT_I(inode); + static struct exfat_cache nohit = { .fcluster = 0, }; + struct exfat_cache *hit = &nohit, *p; + unsigned int offset = EOF_CLUSTER; + + spin_lock(&ei->cache_lru_lock); + list_for_each_entry(p, &ei->cache_lru, cache_list) { + /* Find the cache of "fclus" or nearest cache. */ + if (p->fcluster <= fclus && hit->fcluster < p->fcluster) { + hit = p; + if (hit->fcluster + hit->nr_contig < fclus) { + offset = hit->nr_contig; + } else { + offset = fclus - hit->fcluster; + break; + } + } + } + if (hit != &nohit) { + exfat_cache_update_lru(inode, hit); + + cid->id = ei->cache_valid_id; + cid->nr_contig = hit->nr_contig; + cid->fcluster = hit->fcluster; + cid->dcluster = hit->dcluster; + *cached_fclus = cid->fcluster + offset; + *cached_dclus = cid->dcluster + offset; + } + spin_unlock(&ei->cache_lru_lock); + + return offset; +} + +static struct exfat_cache *exfat_cache_merge(struct inode *inode, + struct exfat_cache_id *new) +{ + struct exfat_inode_info *ei = EXFAT_I(inode); + struct exfat_cache *p; + + list_for_each_entry(p, &ei->cache_lru, cache_list) { + /* Find the same part as "new" in cluster-chain. */ + if (p->fcluster == new->fcluster) { + if (new->nr_contig > p->nr_contig) + p->nr_contig = new->nr_contig; + return p; + } + } + return NULL; +} + +static void exfat_cache_add(struct inode *inode, + struct exfat_cache_id *new) +{ + struct exfat_inode_info *ei = EXFAT_I(inode); + struct exfat_cache *cache, *tmp; + + if (new->fcluster == EOF_CLUSTER) /* dummy cache */ + return; + + spin_lock(&ei->cache_lru_lock); + if (new->id != EXFAT_CACHE_VALID && + new->id != ei->cache_valid_id) + goto unlock; /* this cache was invalidated */ + + cache = exfat_cache_merge(inode, new); + if (cache == NULL) { + if (ei->nr_caches < EXFAT_MAX_CACHE) { + ei->nr_caches++; + spin_unlock(&ei->cache_lru_lock); + + tmp = exfat_cache_alloc(); + if (!tmp) { + spin_lock(&ei->cache_lru_lock); + ei->nr_caches--; + spin_unlock(&ei->cache_lru_lock); + return; + } + + spin_lock(&ei->cache_lru_lock); + cache = exfat_cache_merge(inode, new); + if (cache != NULL) { + ei->nr_caches--; + exfat_cache_free(tmp); + goto out_update_lru; + } + cache = tmp; + } else { + struct list_head *p = ei->cache_lru.prev; + + cache = list_entry(p, + struct exfat_cache, cache_list); + } + cache->fcluster = new->fcluster; + cache->dcluster = new->dcluster; + cache->nr_contig = new->nr_contig; + } +out_update_lru: + exfat_cache_update_lru(inode, cache); +unlock: + spin_unlock(&ei->cache_lru_lock); +} + +/* + * Cache invalidation occurs rarely, thus the LRU chain is not updated. It + * fixes itself after a while. + */ +static void __exfat_cache_inval_inode(struct inode *inode) +{ + struct exfat_inode_info *ei = EXFAT_I(inode); + struct exfat_cache *cache; + + while (!list_empty(&ei->cache_lru)) { + cache = list_entry(ei->cache_lru.next, + struct exfat_cache, cache_list); + list_del_init(&cache->cache_list); + ei->nr_caches--; + exfat_cache_free(cache); + } + /* Update. The copy of caches before this id is discarded. */ + ei->cache_valid_id++; + if (ei->cache_valid_id == EXFAT_CACHE_VALID) + ei->cache_valid_id++; +} + +void exfat_cache_inval_inode(struct inode *inode) +{ + struct exfat_inode_info *ei = EXFAT_I(inode); + + spin_lock(&ei->cache_lru_lock); + __exfat_cache_inval_inode(inode); + spin_unlock(&ei->cache_lru_lock); +} + +static inline int cache_contiguous(struct exfat_cache_id *cid, + unsigned int dclus) +{ + cid->nr_contig++; + return cid->dcluster + cid->nr_contig == dclus; +} + +static inline void cache_init(struct exfat_cache_id *cid, + unsigned int fclus, unsigned int dclus) +{ + cid->id = EXFAT_CACHE_VALID; + cid->fcluster = fclus; + cid->dcluster = dclus; + cid->nr_contig = 0; +} + +int exfat_get_cluster(struct inode *inode, unsigned int cluster, + unsigned int *fclus, unsigned int *dclus, + unsigned int *last_dclus, int allow_eof) +{ + struct super_block *sb = inode->i_sb; + struct exfat_sb_info *sbi = EXFAT_SB(sb); + unsigned int limit = sbi->num_clusters; + struct exfat_inode_info *ei = EXFAT_I(inode); + struct exfat_cache_id cid; + unsigned int content; + + if (ei->start_clu == FREE_CLUSTER) { + exfat_fs_error(sb, + "invalid access to exfat cache (entry 0x%08x)", + ei->start_clu); + return -EIO; + } + + *fclus = 0; + *dclus = ei->start_clu; + *last_dclus = *dclus; + + /* + * Don`t use exfat_cache if zero offset or non-cluster allocation + */ + if (cluster == 0 || *dclus == EOF_CLUSTER) + return 0; + + cache_init(&cid, EOF_CLUSTER, EOF_CLUSTER); + + if (exfat_cache_lookup(inode, cluster, &cid, fclus, dclus) == + EOF_CLUSTER) { + /* + * dummy, always not contiguous + * This is reinitialized by cache_init(), later. + */ + WARN_ON(cid.id != EXFAT_CACHE_VALID || + cid.fcluster != EOF_CLUSTER || + cid.dcluster != EOF_CLUSTER || + cid.nr_contig != 0); + } + + if (*fclus == cluster) + return 0; + + while (*fclus < cluster) { + /* prevent the infinite loop of cluster chain */ + if (*fclus > limit) { + exfat_fs_error(sb, + "detected the cluster chain loop (i_pos %u)", + (*fclus)); + return -EIO; + } + + if (exfat_ent_get(sb, *dclus, &content)) + return -EIO; + + *last_dclus = *dclus; + *dclus = content; + (*fclus)++; + + if (content == EOF_CLUSTER) { + if (!allow_eof) { + exfat_fs_error(sb, + "invalid cluster chain (i_pos %u, last_clus 0x%08x is EOF)", + *fclus, (*last_dclus)); + return -EIO; + } + + break; + } + + if (!cache_contiguous(&cid, *dclus)) + cache_init(&cid, *fclus, *dclus); + } + + exfat_cache_add(inode, &cid); + return 0; +} -- 2.17.1