From: "Caleb D.S. Brzezinski" <calebdsb@protonmail.com>
To: hirofumi@mail.parknet.co.jp
Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
"Caleb D.S. Brzezinski" <calebdsb@protonmail.com>
Subject: [PATCH 2/3] fat: add the msdos_format_name() filename cache
Date: Sun, 29 Aug 2021 14:25:29 +0000 [thread overview]
Message-ID: <20210829142459.56081-3-calebdsb@protonmail.com> (raw)
In-Reply-To: <20210829142459.56081-1-calebdsb@protonmail.com>
Implement the main msdos_format_name() filename cache. If used as a
module, all memory allocated for the cache is freed when the module is
de-registered.
Signed-off-by: Caleb D.S. Brzezinski <calebdsb@protonmail.com>
---
fs/fat/namei_msdos.c | 35 +++++++++++++++++++++++++++++++++++
1 file changed, 35 insertions(+)
diff --git a/fs/fat/namei_msdos.c b/fs/fat/namei_msdos.c
index 7561674b1..f9d4f63c3 100644
--- a/fs/fat/namei_msdos.c
+++ b/fs/fat/namei_msdos.c
@@ -124,6 +124,16 @@ static int msdos_format_name(const unsigned char *name, int len,
unsigned char *walk;
unsigned char c;
int space;
+ u64 hash;
+ struct msdos_name_node *node;
+
+ /* check if the name is already in the cache */
+
+ hash = msdos_fname_hash(name);
+ if (find_fname_in_cache(res, hash))
+ return 0;
+
+ /* The node wasn't in the cache, so format it normally */
if (name[0] == '.') { /* dotfile because . and .. already done */
if (opts->dotsOK) {
@@ -208,6 +218,18 @@ static int msdos_format_name(const unsigned char *name, int len,
while (walk - res < MSDOS_NAME)
*walk++ = ' ';
+ /* allocate memory now */
+ node = kmalloc(sizeof(*node), GFP_KERNEL);
+ if (!node)
+ return -ENOMEM;
+
+ /* fill in the name cache */
+ node->hash = hash;
+ strscpy(node->fname, res, 9);
+ mutex_lock(&msdos_ncache_mutex);
+ hash_add(msdos_ncache, &node->h_list, node->hash);
+ mutex_unlock(&msdos_ncache_mutex);
+
return 0;
}
@@ -677,6 +699,7 @@ static int do_msdos_rename(struct inode *old_dir, unsigned char *old_name,
* shouldn't be serious corruption.
*/
int err2 = fat_remove_entries(new_dir, &sinfo);
+
if (corrupt)
corrupt |= err2;
sinfo.bh = NULL;
@@ -774,6 +797,18 @@ static int __init init_msdos_fs(void)
static void __exit exit_msdos_fs(void)
{
+ int bkt;
+ struct msdos_name_node *c, *prev;
+
+ prev = NULL;
+ /* do this one behind to prevent bad memory access */
+ hash_for_each(msdos_ncache, bkt, c, h_list) {
+ kfree(prev);
+ prev = c;
+ }
+
+ kfree(prev);
+
unregister_filesystem(&msdos_fs_type);
}
--
2.32.0
next prev parent reply other threads:[~2021-08-29 14:25 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-29 14:25 [PATCH 0/3] fat: add a cache for msdos_format_name() Caleb D.S. Brzezinski
2021-08-29 14:25 ` [PATCH 1/3] fat: define functions and data structures for a formatted name cache Caleb D.S. Brzezinski
2021-08-29 21:05 ` kernel test robot
2021-08-29 21:05 ` [RFC PATCH] fat: msdos_ncache can be static kernel test robot
2021-08-29 14:25 ` Caleb D.S. Brzezinski [this message]
2021-08-29 15:11 ` [PATCH 2/3] fat: add the msdos_format_name() filename cache Al Viro
2021-08-29 15:26 ` Al Viro
2021-08-29 17:19 ` Caleb D.S. Brzezinski
2021-08-29 17:11 ` Caleb D.S. Brzezinski
2021-08-29 21:23 ` Al Viro
2021-08-29 14:25 ` [PATCH 3/3] fat: add hash machinery to relevant filesystem operations Caleb D.S. Brzezinski
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