UPSTREAM: f2fs: Introduce linear search for dentries
This patch addresses an issue where some files in case-insensitive
directories become inaccessible due to changes in how the kernel function,
utf8_casefold(), generates case-folded strings from the commit 5c26d2f1d3f5
("unicode: Don't special case ignorable code points").
F2FS uses these case-folded names to calculate hash values for locating
dentries and stores them on disk. Since utf8_casefold() can produce
different output across kernel versions, stored hash values and newly
calculated hash values may differ. This results in affected files no
longer being found via the hash-based lookup.
To resolve this, the patch introduces a linear search fallback.
If the initial hash-based search fails, F2FS will sequentially scan the
directory entries.
Fixes: 5c26d2f1d3f5 ("unicode: Don't special case ignorable code points")
Link: https://bugzilla.kernel.org/show_bug.cgi?id=219586
Change-Id: I0ae32fbbe0dbb29221e9460565a2cca664e47ab4
Signed-off-by: Daniel Lee <chullee@google.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
(cherry picked from commit 91b587ba79e1b68bb718d12b0758dbcdab4e9cb7)
(cherry picked from commit 79f2beb7a4f5f256928e57fd79cc194b422d2694)
diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
index 1880a8d7e..7e76661 100644
--- a/fs/f2fs/dir.c
+++ b/fs/f2fs/dir.c
@@ -199,7 +199,8 @@ static unsigned long dir_block_index(unsigned int level,
static struct f2fs_dir_entry *find_in_block(struct inode *dir,
struct page *dentry_page,
const struct f2fs_filename *fname,
- int *max_slots)
+ int *max_slots,
+ bool use_hash)
{
struct f2fs_dentry_block *dentry_blk;
struct f2fs_dentry_ptr d;
@@ -207,7 +208,7 @@ static struct f2fs_dir_entry *find_in_block(struct inode *dir,
dentry_blk = (struct f2fs_dentry_block *)page_address(dentry_page);
make_dentry_ptr_block(dir, &d, dentry_blk);
- return f2fs_find_target_dentry(&d, fname, max_slots);
+ return f2fs_find_target_dentry(&d, fname, max_slots, use_hash);
}
#ifdef CONFIG_UNICODE
@@ -284,7 +285,8 @@ static inline int f2fs_match_name(const struct inode *dir,
}
struct f2fs_dir_entry *f2fs_find_target_dentry(const struct f2fs_dentry_ptr *d,
- const struct f2fs_filename *fname, int *max_slots)
+ const struct f2fs_filename *fname, int *max_slots,
+ bool use_hash)
{
struct f2fs_dir_entry *de;
unsigned long bit_pos = 0;
@@ -307,7 +309,7 @@ struct f2fs_dir_entry *f2fs_find_target_dentry(const struct f2fs_dentry_ptr *d,
continue;
}
- if (de->hash_code == fname->hash) {
+ if (!use_hash || de->hash_code == fname->hash) {
res = f2fs_match_name(d->inode, fname,
d->filename[bit_pos],
le16_to_cpu(de->name_len));
@@ -334,11 +336,12 @@ struct f2fs_dir_entry *f2fs_find_target_dentry(const struct f2fs_dentry_ptr *d,
static struct f2fs_dir_entry *find_in_level(struct inode *dir,
unsigned int level,
const struct f2fs_filename *fname,
- struct page **res_page)
+ struct page **res_page,
+ bool use_hash)
{
int s = GET_DENTRY_SLOTS(fname->disk_name.len);
unsigned int nbucket, nblock;
- unsigned int bidx, end_block;
+ unsigned int bidx, end_block, bucket_no;
struct page *dentry_page;
struct f2fs_dir_entry *de = NULL;
bool room = false;
@@ -347,8 +350,11 @@ static struct f2fs_dir_entry *find_in_level(struct inode *dir,
nbucket = dir_buckets(level, F2FS_I(dir)->i_dir_level);
nblock = bucket_blocks(level);
+ bucket_no = use_hash ? le32_to_cpu(fname->hash) % nbucket : 0;
+
+start_find_bucket:
bidx = dir_block_index(level, F2FS_I(dir)->i_dir_level,
- le32_to_cpu(fname->hash) % nbucket);
+ bucket_no);
end_block = bidx + nblock;
for (; bidx < end_block; bidx++) {
@@ -364,7 +370,7 @@ static struct f2fs_dir_entry *find_in_level(struct inode *dir,
}
}
- de = find_in_block(dir, dentry_page, fname, &max_slots);
+ de = find_in_block(dir, dentry_page, fname, &max_slots, use_hash);
if (IS_ERR(de)) {
*res_page = ERR_CAST(de);
de = NULL;
@@ -379,12 +385,18 @@ static struct f2fs_dir_entry *find_in_level(struct inode *dir,
f2fs_put_page(dentry_page, 0);
}
- if (!de && room && F2FS_I(dir)->chash != fname->hash) {
- F2FS_I(dir)->chash = fname->hash;
- F2FS_I(dir)->clevel = level;
- }
+ if (de)
+ return de;
- return de;
+ if (likely(use_hash)) {
+ if (room && F2FS_I(dir)->chash != fname->hash) {
+ F2FS_I(dir)->chash = fname->hash;
+ F2FS_I(dir)->clevel = level;
+ }
+ } else if (++bucket_no < nbucket) {
+ goto start_find_bucket;
+ }
+ return NULL;
}
struct f2fs_dir_entry *__f2fs_find_entry(struct inode *dir,
@@ -395,11 +407,15 @@ struct f2fs_dir_entry *__f2fs_find_entry(struct inode *dir,
struct f2fs_dir_entry *de = NULL;
unsigned int max_depth;
unsigned int level;
+ bool use_hash = true;
*res_page = NULL;
+#if IS_ENABLED(CONFIG_UNICODE)
+start_find_entry:
+#endif
if (f2fs_has_inline_dentry(dir)) {
- de = f2fs_find_in_inline_dir(dir, fname, res_page);
+ de = f2fs_find_in_inline_dir(dir, fname, res_page, use_hash);
goto out;
}
@@ -415,11 +431,18 @@ struct f2fs_dir_entry *__f2fs_find_entry(struct inode *dir,
}
for (level = 0; level < max_depth; level++) {
- de = find_in_level(dir, level, fname, res_page);
+ de = find_in_level(dir, level, fname, res_page, use_hash);
if (de || IS_ERR(*res_page))
break;
}
+
out:
+#if IS_ENABLED(CONFIG_UNICODE)
+ if (IS_CASEFOLDED(dir) && !de && use_hash) {
+ use_hash = false;
+ goto start_find_entry;
+ }
+#endif
/* This is to increase the speed of f2fs_create */
if (!de)
F2FS_I(dir)->task = current;
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index a781078..e624bf4 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -3389,7 +3389,8 @@ int f2fs_prepare_lookup(struct inode *dir, struct dentry *dentry,
struct f2fs_filename *fname);
void f2fs_free_filename(struct f2fs_filename *fname);
struct f2fs_dir_entry *f2fs_find_target_dentry(const struct f2fs_dentry_ptr *d,
- const struct f2fs_filename *fname, int *max_slots);
+ const struct f2fs_filename *fname, int *max_slots,
+ bool use_hash);
int f2fs_fill_dentries(struct dir_context *ctx, struct f2fs_dentry_ptr *d,
unsigned int start_pos, struct fscrypt_str *fstr);
void f2fs_do_make_empty_dir(struct inode *inode, struct inode *parent,
@@ -3987,7 +3988,8 @@ int f2fs_write_inline_data(struct inode *inode, struct page *page);
int f2fs_recover_inline_data(struct inode *inode, struct page *npage);
struct f2fs_dir_entry *f2fs_find_in_inline_dir(struct inode *dir,
const struct f2fs_filename *fname,
- struct page **res_page);
+ struct page **res_page,
+ bool use_hash);
int f2fs_make_empty_inline_dir(struct inode *inode, struct inode *parent,
struct page *ipage);
int f2fs_add_inline_entry(struct inode *dir, const struct f2fs_filename *fname,
diff --git a/fs/f2fs/inline.c b/fs/f2fs/inline.c
index cef1715..4b7e1a9 100644
--- a/fs/f2fs/inline.c
+++ b/fs/f2fs/inline.c
@@ -331,7 +331,8 @@ int f2fs_recover_inline_data(struct inode *inode, struct page *npage)
struct f2fs_dir_entry *f2fs_find_in_inline_dir(struct inode *dir,
const struct f2fs_filename *fname,
- struct page **res_page)
+ struct page **res_page,
+ bool use_hash)
{
struct f2fs_sb_info *sbi = F2FS_SB(dir->i_sb);
struct f2fs_dir_entry *de;
@@ -348,7 +349,7 @@ struct f2fs_dir_entry *f2fs_find_in_inline_dir(struct inode *dir,
inline_dentry = inline_data_addr(dir, ipage);
make_dentry_ptr_inline(dir, &d, inline_dentry);
- de = f2fs_find_target_dentry(&d, fname, NULL);
+ de = f2fs_find_target_dentry(&d, fname, NULL, use_hash);
unlock_page(ipage);
if (IS_ERR(de)) {
*res_page = ERR_CAST(de);
