From: gaoxiang25@huawei.com (Gao Xiang)
Subject: [PATCH v6 08/24] erofs: add namei functions
Date: Fri, 2 Aug 2019 20:53:31 +0800 [thread overview]
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 other threads:[~2019-08-02 12:53 UTC|newest]
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
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