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Message-Id: <1495398051-4604-4-git-send-email-richard@nod.at>
Date: Sun, 21 May 2017 22:20:48 +0200
From: Richard Weinberger <richard@....at>
To: linux-mtd@...ts.infradead.org
Cc: david@...ma-star.at, dedekind1@...il.com, adrian.hunter@...el.com,
linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org,
adilger.kernel@...ger.ca, akpm@...ux-foundation.org,
linux-ext4@...r.kernel.org, bfields@...hat.com,
marcus.folkesson@...il.com, hyc.lee@...il.com,
rockdotlee@...il.com, leon.pollak@...il.com,
Richard Weinberger <richard@....at>
Subject: [PATCH 3/6] ubifs: Use 64bit readdir cookies
This is the first step to support proper telldir/seekdir()
in UBIFS.
Let's report 64bit cookies in readdir(). The cookie is a combination
of the entry key plus the double hash value.
Signed-off-by: Richard Weinberger <richard@....at>
Reviewed-by: J. Bruce Fields <bfields@...hat.com>
---
fs/ubifs/dir.c | 46 +++++++++++++++++++++++++++++++-----------
fs/ubifs/key.h | 61 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
fs/ubifs/ubifs.h | 1 +
3 files changed, 96 insertions(+), 12 deletions(-)
diff --git a/fs/ubifs/dir.c b/fs/ubifs/dir.c
index cada60690c22..e79b529df9c3 100644
--- a/fs/ubifs/dir.c
+++ b/fs/ubifs/dir.c
@@ -540,7 +540,7 @@ static int ubifs_readdir(struct file *file, struct dir_context *ctx)
dbg_gen("dir ino %lu, f_pos %#llx", dir->i_ino, ctx->pos);
- if (ctx->pos > UBIFS_S_KEY_HASH_MASK || ctx->pos == 2)
+ if (ctx->pos == 2)
/*
* The directory was seek'ed to a senseless position or there
* are no more entries.
@@ -595,7 +595,7 @@ static int ubifs_readdir(struct file *file, struct dir_context *ctx)
goto out;
}
- ctx->pos = key_hash_flash(c, &dent->key);
+ ctx->pos = key_get_dir_pos(c, file, dent);
file->private_data = dent;
}
@@ -605,21 +605,43 @@ static int ubifs_readdir(struct file *file, struct dir_context *ctx)
* The directory was seek'ed to and is now readdir'ed.
* Find the entry corresponding to @ctx->pos or the closest one.
*/
- dent_key_init_hash(c, &key, dir->i_ino, ctx->pos);
- fname_len(&nm) = 0;
- dent = ubifs_tnc_next_ent(c, &key, &nm);
- if (IS_ERR(dent)) {
- err = PTR_ERR(dent);
- goto out;
+ dent_key_init_hash(c, &key, dir->i_ino,
+ key_get_hash_from_dir_pos(c, file, ctx->pos));
+
+ if (key_want_short_hash(file)) {
+ err = -ENOENT;
+ } else {
+ dent = kmalloc(UBIFS_MAX_DENT_NODE_SZ, GFP_NOFS);
+ if (!dent) {
+ err = -ENOMEM;
+ goto out;
+ }
+
+ err = ubifs_tnc_lookup_dh(c, &key, dent,
+ key_get_cookie_from_dir_pos(c, ctx->pos));
+ }
+
+ if (err) {
+ kfree(dent);
+ if (err < 0 && err != -ENOENT && err != -EOPNOTSUPP)
+ goto out;
+
+ fname_len(&nm) = 0;
+ dent = ubifs_tnc_next_ent(c, &key, &nm);
+ if (IS_ERR(dent)) {
+ err = PTR_ERR(dent);
+ goto out;
+ }
}
- ctx->pos = key_hash_flash(c, &dent->key);
+
+ ctx->pos = key_get_dir_pos(c, file, dent);
file->private_data = dent;
}
while (1) {
- dbg_gen("ino %llu, new f_pos %#x",
+ dbg_gen("ino %llu, new f_pos %#lx",
(unsigned long long)le64_to_cpu(dent->inum),
- key_hash_flash(c, &dent->key));
+ (unsigned long)key_get_dir_pos(c, file, dent));
ubifs_assert(le64_to_cpu(dent->ch.sqnum) >
ubifs_inode(dir)->creat_sqnum);
@@ -657,7 +679,7 @@ static int ubifs_readdir(struct file *file, struct dir_context *ctx)
}
kfree(file->private_data);
- ctx->pos = key_hash_flash(c, &dent->key);
+ ctx->pos = key_get_dir_pos(c, file, dent);
file->private_data = dent;
cond_resched();
}
diff --git a/fs/ubifs/key.h b/fs/ubifs/key.h
index 7547be512db2..763188649133 100644
--- a/fs/ubifs/key.h
+++ b/fs/ubifs/key.h
@@ -397,6 +397,67 @@ static inline uint32_t key_hash_flash(const struct ubifs_info *c, const void *k)
}
/**
+ * key_want_short_hash - tests whether we can emit a 64bit hash or not.
+ * @file: the file handle of the directory
+ */
+static inline bool key_want_short_hash(struct file *file)
+{
+ if (file->f_mode & FMODE_32BITHASH)
+ return true;
+
+ if (!(file->f_mode & FMODE_64BITHASH) && is_32bit_api())
+ return true;
+
+ return false;
+}
+
+/**
+ * key_dir_pos - compute a 64bit directory cookie for readdir()
+ * @c: UBIFS file-system description object
+ * @file: the file handle of the directory
+ * @dent: the directory entry
+ */
+static inline loff_t key_get_dir_pos(const struct ubifs_info *c,
+ struct file *file,
+ struct ubifs_dent_node *dent)
+{
+ BUILD_BUG_ON(sizeof(loff_t) < 8);
+
+ if (key_want_short_hash(file))
+ return key_hash_flash(c, &dent->key);
+
+ return ((loff_t)key_hash_flash(c, &dent->key)) << UBIFS_DH_BITS |
+ le32_to_cpu(dent->cookie);
+}
+
+/**
+ * key_get_hash_from_dir_pos - extracts the flash key from a directory offset.
+ * @c: UBIFS file-system description object
+ * @file: the file handle of the directory
+ * @pos: the directory offset provied by VFS
+ */
+static inline uint32_t key_get_hash_from_dir_pos(const struct ubifs_info *c,
+ struct file *file, loff_t pos)
+{
+ if (key_want_short_hash(file))
+ return pos & UBIFS_S_KEY_HASH_MASK;
+
+ return (pos >> UBIFS_DH_BITS) & UBIFS_S_KEY_HASH_MASK;
+}
+
+/**
+ * key_get_cookie_from_dir_pos - extracts the double hash cookie from a
+ * directory offset.
+ * @c: UBIFS file-system description object
+ * @pos: the directory offset provied by VFS
+ */
+static inline uint32_t key_get_cookie_from_dir_pos(const struct ubifs_info *c,
+ loff_t pos)
+{
+ return pos & UBIFS_DH_MASK;
+}
+
+/**
* key_block - get data block number.
* @c: UBIFS file-system description object
* @key: the key to get the block number from
diff --git a/fs/ubifs/ubifs.h b/fs/ubifs/ubifs.h
index 298b4d89eee9..f14dcc890e47 100644
--- a/fs/ubifs/ubifs.h
+++ b/fs/ubifs/ubifs.h
@@ -44,6 +44,7 @@
#include <linux/fscrypt_notsupp.h>
#endif
#include <linux/random.h>
+#include <linux/compat.h>
#include "ubifs-media.h"
/* Version of this UBIFS implementation */
--
2.12.0
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