From: gaoxiang25@huawei.com (Gao Xiang) Subject: [PATCH v6 08/24] erofs: add namei functions Date: Fri, 2 Aug 2019 20:53:31 +0800 Message-ID: <20190802125347.166018-9-gaoxiang25@huawei.com> (raw) In-Reply-To: <20190802125347.166018-1-gaoxiang25@huawei.com> This commit adds functions that transfer names to inodes. Signed-off-by: Gao Xiang <gaoxiang25 at huawei.com> --- fs/erofs/namei.c | 247 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 247 insertions(+) create mode 100644 fs/erofs/namei.c diff --git a/fs/erofs/namei.c b/fs/erofs/namei.c new file mode 100644 index 000000000000..73bf61637907 --- /dev/null +++ b/fs/erofs/namei.c @@ -0,0 +1,247 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * linux/fs/erofs/namei.c + * + * Copyright (C) 2017-2018 HUAWEI, Inc. + * http://www.huawei.com/ + * Created by Gao Xiang <gaoxiang25 at huawei.com> + */ +#include "internal.h" + +#include <trace/events/erofs.h> + +struct erofs_qstr { + const unsigned char *name; + const unsigned char *end; +}; + +/* based on the end of qn is accurate and it must have the trailing '\0' */ +static inline int dirnamecmp(const struct erofs_qstr *qn, + const struct erofs_qstr *qd, + unsigned int *matched) +{ + unsigned int i = *matched; + + /* + * on-disk error, let's only BUG_ON in the debugging mode. + * otherwise, it will return 1 to just skip the invalid name + * and go on (in consideration of the lookup performance). + */ + DBG_BUGON(qd->name > qd->end); + + /* qd could not have trailing '\0' */ + /* However it is absolutely safe if < qd->end */ + while (qd->name + i < qd->end && qd->name[i] != '\0') { + if (qn->name[i] != qd->name[i]) { + *matched = i; + return qn->name[i] > qd->name[i] ? 1 : -1; + } + ++i; + } + *matched = i; + /* See comments in __d_alloc on the terminating NUL character */ + return qn->name[i] == '\0' ? 0 : 1; +} + +#define nameoff_from_disk(off, sz) (le16_to_cpu(off) & ((sz) - 1)) + +static struct erofs_dirent *find_target_dirent(struct erofs_qstr *name, + u8 *data, + unsigned int dirblksize, + const int ndirents) +{ + int head, back; + unsigned int startprfx, endprfx; + struct erofs_dirent *const de = (struct erofs_dirent *)data; + + /* since the 1st dirent has been evaluated previously */ + head = 1; + back = ndirents - 1; + startprfx = endprfx = 0; + + while (head <= back) { + const int mid = head + (back - head) / 2; + const int nameoff = nameoff_from_disk(de[mid].nameoff, + dirblksize); + unsigned int matched = min(startprfx, endprfx); + struct erofs_qstr dname = { + .name = data + nameoff, + .end = unlikely(mid >= ndirents - 1) ? + data + dirblksize : + data + nameoff_from_disk(de[mid + 1].nameoff, + dirblksize) + }; + + /* string comparison without already matched prefix */ + int ret = dirnamecmp(name, &dname, &matched); + + if (unlikely(!ret)) { + return de + mid; + } else if (ret > 0) { + head = mid + 1; + startprfx = matched; + } else { + back = mid - 1; + endprfx = matched; + } + } + + return ERR_PTR(-ENOENT); +} + +static struct page *find_target_block_classic(struct inode *dir, + struct erofs_qstr *name, + int *_ndirents) +{ + unsigned int startprfx, endprfx; + int head, back; + struct address_space *const mapping = dir->i_mapping; + struct page *candidate = ERR_PTR(-ENOENT); + + startprfx = endprfx = 0; + head = 0; + back = inode_datablocks(dir) - 1; + + while (head <= back) { + const int mid = head + (back - head) / 2; + struct page *page = read_mapping_page(mapping, mid, NULL); + + if (!IS_ERR(page)) { + struct erofs_dirent *de = kmap_atomic(page); + const int nameoff = nameoff_from_disk(de->nameoff, + EROFS_BLKSIZ); + const int ndirents = nameoff / sizeof(*de); + int diff; + unsigned int matched; + struct erofs_qstr dname; + + if (unlikely(!ndirents)) { + DBG_BUGON(1); + kunmap_atomic(de); + put_page(page); + page = ERR_PTR(-EIO); + goto out; + } + + matched = min(startprfx, endprfx); + + dname.name = (u8 *)de + nameoff; + if (ndirents == 1) + dname.end = (u8 *)de + EROFS_BLKSIZ; + else + dname.end = (u8 *)de + + nameoff_from_disk(de[1].nameoff, + EROFS_BLKSIZ); + + /* string comparison without already matched prefix */ + diff = dirnamecmp(name, &dname, &matched); + kunmap_atomic(de); + + if (unlikely(!diff)) { + *_ndirents = 0; + goto out; + } else if (diff > 0) { + head = mid + 1; + startprfx = matched; + + if (!IS_ERR(candidate)) + put_page(candidate); + candidate = page; + *_ndirents = ndirents; + } else { + put_page(page); + + back = mid - 1; + endprfx = matched; + } + continue; + } +out: /* free if the candidate is valid */ + if (!IS_ERR(candidate)) + put_page(candidate); + return page; + } + return candidate; +} + +int erofs_namei(struct inode *dir, + struct qstr *name, + erofs_nid_t *nid, unsigned int *d_type) +{ + int ndirents; + struct page *page; + void *data; + struct erofs_dirent *de; + struct erofs_qstr qn; + + if (unlikely(!dir->i_size)) + return -ENOENT; + + qn.name = name->name; + qn.end = name->name + name->len; + + ndirents = 0; + page = find_target_block_classic(dir, &qn, &ndirents); + + if (IS_ERR(page)) + return PTR_ERR(page); + + data = kmap_atomic(page); + /* the target page has been mapped */ + if (ndirents) + de = find_target_dirent(&qn, data, EROFS_BLKSIZ, ndirents); + else + de = (struct erofs_dirent *)data; + + if (!IS_ERR(de)) { + *nid = le64_to_cpu(de->nid); + *d_type = de->file_type; + } + + kunmap_atomic(data); + put_page(page); + + return PTR_ERR_OR_ZERO(de); +} + +/* NOTE: i_mutex is already held by vfs */ +static struct dentry *erofs_lookup(struct inode *dir, + struct dentry *dentry, + unsigned int flags) +{ + int err; + erofs_nid_t nid; + unsigned int d_type; + struct inode *inode; + + DBG_BUGON(!d_really_is_negative(dentry)); + /* dentry must be unhashed in lookup, no need to worry about */ + DBG_BUGON(!d_unhashed(dentry)); + + trace_erofs_lookup(dir, dentry, flags); + + /* file name exceeds fs limit */ + if (unlikely(dentry->d_name.len > EROFS_NAME_LEN)) + return ERR_PTR(-ENAMETOOLONG); + + /* false uninitialized warnings on gcc 4.8.x */ + err = erofs_namei(dir, &dentry->d_name, &nid, &d_type); + + if (err == -ENOENT) { + /* negative dentry */ + inode = NULL; + } else if (unlikely(err)) { + inode = ERR_PTR(err); + } else { + debugln("%s, %s (nid %llu) found, d_type %u", __func__, + dentry->d_name.name, nid, d_type); + inode = erofs_iget(dir->i_sb, nid, d_type == EROFS_FT_DIR); + } + return d_splice_alias(inode, dentry); +} + +const struct inode_operations erofs_dir_iops = { + .lookup = erofs_lookup, + .getattr = erofs_getattr, +}; + -- 2.17.1
next prev parent reply index Thread overview: 141+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-08-02 12:53 [PATCH v6 00/24] erofs: promote erofs from staging Gao Xiang 2019-08-02 12:53 ` [PATCH v6 01/24] erofs: add on-disk layout Gao Xiang [not found] ` <20190829095954.GB20598@infradead.org> 2019-09-01 7:54 ` Gao Xiang 2019-09-02 12:45 ` Christoph Hellwig 2019-09-02 13:02 ` Gao Xiang 2019-09-02 8:40 ` Pavel Machek 2019-09-02 10:35 ` Gao Xiang [not found] ` <20190829103252.GA64893@architecture4> [not found] ` <67d6efbbc9ac6db23215660cb970b7ef29dc0c1d.camel@perches.com> [not found] ` <20190830120714.GN2752@twin.jikos.cz> 2019-09-02 8:43 ` Pavel Machek 2019-09-02 14:07 ` David Sterba 2019-09-03 11:27 ` Pavel Machek 2019-08-02 12:53 ` [PATCH v6 02/24] erofs: add erofs in-memory stuffs Gao Xiang 2019-08-02 12:53 ` [PATCH v6 03/24] erofs: add super block operations Gao Xiang [not found] ` <20190829101545.GC20598@infradead.org> [not found] ` <20190829105048.GB64893@architecture4> 2019-08-30 16:39 ` Christoph Hellwig 2019-08-30 17:15 ` Gao Xiang 2019-08-31 0:54 ` Gao Xiang 2019-08-31 6:34 ` Amir Goldstein 2019-08-31 6:48 ` Gao Xiang 2019-09-01 8:54 ` Gao Xiang 2019-09-02 12:51 ` Christoph Hellwig 2019-09-02 14:43 ` Gao Xiang 2019-09-02 15:19 ` Christoph Hellwig 2019-09-02 15:24 ` Gao Xiang 2019-08-02 12:53 ` [PATCH v6 04/24] erofs: add raw address_space operations Gao Xiang [not found] ` <20190829101721.GD20598@infradead.org> [not found] ` <20190829114610.GF64893@architecture4> 2019-08-30 16:40 ` Christoph Hellwig 2019-08-30 17:23 ` Gao Xiang 2019-08-02 12:53 ` [PATCH v6 05/24] erofs: add inode operations Gao Xiang [not found] ` <20190829102426.GE20598@infradead.org> [not found] ` <20190829115922.GG64893@architecture4> 2019-08-30 16:42 ` Christoph Hellwig 2019-08-30 18:46 ` Gao Xiang 2019-09-01 9:34 ` Gao Xiang 2019-09-02 12:53 ` Christoph Hellwig 2019-09-02 13:43 ` David Sterba 2019-09-02 13:55 ` Gao Xiang 2019-08-02 12:53 ` [PATCH v6 06/24] erofs: support special inode Gao Xiang [not found] ` <20190829102503.GF20598@infradead.org> 2019-09-01 9:39 ` Gao Xiang 2019-08-02 12:53 ` [PATCH v6 07/24] erofs: add directory operations Gao Xiang 2019-08-02 12:53 ` Gao Xiang [this message] 2019-08-02 12:53 ` [PATCH v6 09/24] erofs: support tracepoint Gao Xiang 2019-08-02 12:53 ` [PATCH v6 10/24] erofs: update Kconfig and Makefile Gao Xiang 2019-08-02 12:53 ` [PATCH v6 11/24] erofs: introduce xattr & posixacl support Gao Xiang 2019-08-02 12:53 ` [PATCH v6 12/24] erofs: introduce tagged pointer Gao Xiang 2019-08-02 12:53 ` [PATCH v6 13/24] erofs: add compression indexes support Gao Xiang 2019-08-02 12:53 ` [PATCH v6 14/24] erofs: introduce superblock registration Gao Xiang 2019-08-02 12:53 ` [PATCH v6 15/24] erofs: introduce erofs shrinker Gao Xiang 2019-08-02 12:53 ` [PATCH v6 16/24] erofs: introduce workstation for decompression Gao Xiang 2019-08-02 12:53 ` [PATCH v6 17/24] erofs: introduce per-CPU buffers implementation Gao Xiang 2019-08-02 12:53 ` [PATCH v6 18/24] erofs: introduce pagevec for decompression subsystem Gao Xiang 2019-08-02 12:53 ` [PATCH v6 19/24] erofs: add erofs_allocpage() Gao Xiang 2019-08-02 12:53 ` [PATCH v6 20/24] erofs: introduce generic decompression backend Gao Xiang 2019-08-02 12:53 ` [PATCH v6 21/24] erofs: introduce LZ4 decompression inplace Gao Xiang 2019-08-02 12:53 ` [PATCH v6 22/24] erofs: introduce the decompression frontend Gao Xiang 2019-08-02 12:53 ` [PATCH v6 23/24] erofs: introduce cached decompression Gao Xiang 2019-08-02 12:53 ` [PATCH v6 24/24] erofs: add document Gao Xiang 2019-09-01 5:51 ` [PATCH 00/21] erofs: patchset addressing Christoph's comments Gao Xiang 2019-09-01 5:51 ` [PATCH 01/21] erofs: remove all the byte offset comments Gao Xiang 2019-09-02 12:05 ` Christoph Hellwig 2019-09-01 5:51 ` [PATCH 02/21] erofs: on-disk format should have explicitly assigned numbers Gao Xiang 2019-09-02 12:05 ` Christoph Hellwig 2019-09-01 5:51 ` [PATCH 03/21] erofs: some macros are much more readable as a function Gao Xiang 2019-09-02 12:06 ` Christoph Hellwig 2019-09-01 5:51 ` [PATCH 04/21] erofs: kill __packed for on-disk structures Gao Xiang 2019-09-02 12:06 ` Christoph Hellwig 2019-09-01 5:51 ` [PATCH 05/21] erofs: update erofs_inode_is_data_compressed helper Gao Xiang 2019-09-02 12:07 ` Christoph Hellwig 2019-09-01 5:51 ` [PATCH 06/21] erofs: kill erofs_{init,exit}_inode_cache Gao Xiang 2019-09-02 12:09 ` Christoph Hellwig 2019-09-01 5:51 ` [PATCH 07/21] erofs: use erofs_inode naming Gao Xiang 2019-09-02 12:10 ` Christoph Hellwig 2019-09-02 12:13 ` Gao Xiang 2019-09-02 12:47 ` Christoph Hellwig 2019-09-02 13:33 ` Gao Xiang 2019-09-01 5:51 ` [PATCH 08/21] erofs: update comments in inode.c Gao Xiang 2019-09-01 5:51 ` [PATCH 09/21] erofs: update erofs symlink stuffs Gao Xiang 2019-09-02 12:11 ` Christoph Hellwig 2019-09-01 5:51 ` [PATCH 10/21] erofs: kill is_inode_layout_compression() Gao Xiang 2019-09-02 12:11 ` Christoph Hellwig 2019-09-01 5:51 ` [PATCH 11/21] erofs: use dsb instead of layout for ondisk super_block Gao Xiang 2019-09-02 12:12 ` Christoph Hellwig 2019-09-02 12:15 ` Gao Xiang 2019-09-01 5:51 ` [PATCH 12/21] erofs: kill verbose debug info in erofs_fill_super Gao Xiang 2019-09-02 12:14 ` Christoph Hellwig 2019-09-02 12:18 ` Gao Xiang 2019-09-01 5:51 ` [PATCH 13/21] erofs: simplify erofs_grab_bio() since bio_alloc() never fail Gao Xiang 2019-09-02 12:20 ` Christoph Hellwig 2019-09-01 5:51 ` [PATCH 14/21] erofs: kill prio and nofail of erofs_get_meta_page() Gao Xiang 2019-09-02 12:21 ` Christoph Hellwig 2019-09-01 5:51 ` [PATCH 15/21] erofs: kill __submit_bio() Gao Xiang 2019-09-01 5:51 ` [PATCH 16/21] erofs: kill magic underscores Gao Xiang 2019-09-02 12:26 ` Christoph Hellwig 2019-09-02 12:39 ` Gao Xiang 2019-09-02 12:54 ` Christoph Hellwig 2019-09-02 13:38 ` Gao Xiang 2019-09-01 5:51 ` [PATCH 17/21] erofs: use a switch statement when dealing with the file modes Gao Xiang 2019-09-02 12:27 ` Christoph Hellwig 2019-09-01 5:51 ` [PATCH 18/21] erofs: add "erofs_" prefix for common and short functions Gao Xiang 2019-09-02 12:28 ` Christoph Hellwig 2019-09-01 5:51 ` [PATCH 19/21] erofs: kill all erofs specific fault injection Gao Xiang 2019-09-02 12:28 ` Christoph Hellwig 2019-09-01 5:51 ` [PATCH 20/21] erofs: kill use_vmap module parameter Gao Xiang 2019-09-02 12:31 ` Christoph Hellwig 2019-09-02 12:43 ` Gao Xiang 2019-09-01 5:51 ` [PATCH 21/21] erofs: save one level of indentation Gao Xiang 2019-09-02 12:31 ` Christoph Hellwig 2019-09-02 12:46 ` [PATCH 00/21] erofs: patchset addressing Christoph's comments Christoph Hellwig 2019-09-02 14:24 ` Gao Xiang 2019-09-02 15:23 ` Christoph Hellwig 2019-09-02 15:50 ` Gao Xiang 2019-09-03 6:58 ` Christoph Hellwig 2019-09-03 8:17 ` Gao Xiang 2019-09-03 15:37 ` Christoph Hellwig 2019-09-03 15:43 ` Gao Xiang 2019-09-04 2:08 ` [PATCH v2 00/25] " Gao Xiang 2019-09-04 2:08 ` [PATCH v2 01/25] erofs: remove all the byte offset comments Gao Xiang 2019-09-04 2:08 ` [PATCH v2 02/25] erofs: on-disk format should have explicitly assigned numbers Gao Xiang 2019-09-04 2:08 ` [PATCH v2 03/25] erofs: some macros are much more readable as a function Gao Xiang 2019-09-04 2:08 ` [PATCH v2 04/25] erofs: kill __packed for on-disk structures Gao Xiang 2019-09-04 2:08 ` [PATCH v2 05/25] erofs: update erofs_inode_is_data_compressed helper Gao Xiang 2019-09-04 2:08 ` [PATCH v2 06/25] erofs: use feature_incompat rather than requirements Gao Xiang 2019-09-04 2:08 ` [PATCH v2 07/25] erofs: better naming for erofs inode related stuffs Gao Xiang 2019-09-04 2:08 ` [PATCH v2 08/25] erofs: kill erofs_{init,exit}_inode_cache Gao Xiang 2019-09-04 2:08 ` [PATCH v2 09/25] erofs: use erofs_inode naming Gao Xiang 2019-09-04 2:08 ` [PATCH v2 10/25] erofs: update erofs_fs.h comments Gao Xiang 2019-09-04 2:08 ` [PATCH v2 11/25] erofs: update comments in inode.c Gao Xiang 2019-09-04 2:08 ` [PATCH v2 12/25] erofs: better erofs symlink stuffs Gao Xiang 2019-09-04 2:09 ` [PATCH v2 13/25] erofs: use dsb instead of layout for ondisk super_block Gao Xiang 2019-09-04 2:09 ` [PATCH v2 14/25] erofs: kill verbose debug info in erofs_fill_super Gao Xiang 2019-09-04 2:09 ` [PATCH v2 15/25] erofs: localize erofs_grab_bio() Gao Xiang 2019-09-04 2:09 ` [PATCH v2 16/25] erofs: kill prio and nofail of erofs_get_meta_page() Gao Xiang 2019-09-04 2:09 ` [PATCH v2 17/25] erofs: kill __submit_bio() Gao Xiang 2019-09-04 2:09 ` [PATCH v2 18/25] erofs: add "erofs_" prefix for common and short functions Gao Xiang 2019-09-04 2:09 ` [PATCH v2 19/25] erofs: kill all erofs specific fault injection Gao Xiang 2019-09-04 2:09 ` [PATCH v2 20/25] erofs: kill use_vmap module parameter Gao Xiang 2019-09-04 2:09 ` [PATCH v2 21/25] erofs: save one level of indentation Gao Xiang 2019-09-04 2:09 ` [PATCH v2 22/25] erofs: rename errln/infoln/debugln to erofs_{err, info, dbg} Gao Xiang 2019-09-04 2:09 ` [PATCH v2 23/25] erofs: use read_mapping_page instead of sb_bread Gao Xiang 2019-09-04 2:09 ` [PATCH v2 24/25] erofs: always use iget5_locked Gao Xiang 2019-09-04 2:09 ` [PATCH v2 25/25] erofs: use read_cache_page_gfp for erofs_get_meta_page Gao Xiang 2019-09-04 3:27 ` [PATCH v2 00/25] erofs: patchset addressing Christoph's comments Chao Yu 2019-09-05 1:03 ` Gao Xiang 2019-09-05 11:30 ` Christoph Hellwig 2019-09-04 5:16 ` Christoph Hellwig 2019-09-04 6:08 ` Gao Xiang
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=20190802125347.166018-9-gaoxiang25@huawei.com \ --to=gaoxiang25@huawei.com \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: link
DriverDev-Devel Archive on lore.kernel.org Archives are clonable: git clone --mirror https://lore.kernel.org/driverdev-devel/0 driverdev-devel/git/0.git # If you have public-inbox 1.1+ installed, you may # initialize and index your mirror using the following commands: public-inbox-init -V2 driverdev-devel driverdev-devel/ https://lore.kernel.org/driverdev-devel \ driverdev-devel@linuxdriverproject.org devel@driverdev.osuosl.org public-inbox-index driverdev-devel Example config snippet for mirrors Newsgroup available over NNTP: nntp://nntp.lore.kernel.org/org.linuxdriverproject.driverdev-devel AGPL code for this site: git clone https://public-inbox.org/public-inbox.git