On 2024/12/20 12:59, Daniel Lee wrote:
On Thu, Dec 19, 2024 at 5:29 AM Chao Yu <c...@kernel.org> wrote:Hi Daniel, On 2024/12/17 15:55, Daniel Lee wrote: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.Need a fixes line?Thanks. I will add the commit 5c26d2f1d3f5 to the Fixes:Link: https://bugzilla.kernel.org/show_bug.cgi?id=219586 Signed-off-by: Daniel Lee <chul...@google.com> --- fs/f2fs/dir.c | 38 ++++++++++++++++++++++++++++---------- fs/f2fs/f2fs.h | 6 ++++-- fs/f2fs/inline.c | 5 +++-- 3 files changed, 35 insertions(+), 14 deletions(-) diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c index 47a5c806cf16..a85d19b4e178 100644 --- a/fs/f2fs/dir.c +++ b/fs/f2fs/dir.c @@ -175,7 +175,8 @@ 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; @@ -183,7 +184,7 @@ 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); } static inline int f2fs_match_name(const struct inode *dir, @@ -208,7 +209,8 @@ 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; @@ -231,7 +233,7 @@ 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)); @@ -258,11 +260,12 @@ 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; pgoff_t next_pgofs; @@ -272,8 +275,11 @@ 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; while (bidx < end_block) { @@ -290,7 +296,7 @@ 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; @@ -307,6 +313,9 @@ static struct f2fs_dir_entry *find_in_level(struct inode *dir, bidx++; } + if (!use_hash && !de && ++bucket_no < nbucket) + goto start_find_bucket; + if (!de && room && F2FS_I(dir)->chash != fname->hash) {Do we need to avoid accessing or assigning hash if use_hash is false?Is it still worth keeping the hash for the creation if both hash-based and linear searches failed?
It needs to be kept for hash-based searching failure? since it was added to enhance performance of file creation: - open(..., O_CREAT) - f2fs_lookup : didn't find target dirent, then, record last chash & clevel - f2fs_create : create dirent in clevel bucket once chash matches Thanks,
Thanks,F2FS_I(dir)->chash = fname->hash; F2FS_I(dir)->clevel = level; @@ -323,11 +332,13 @@ 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; +start_find_entry: 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; } @@ -343,11 +354,18 @@ 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 f523dd302bf6..1afebb9c4061 100644 --- a/fs/f2fs/f2fs.h +++ b/fs/f2fs/f2fs.h @@ -3588,7 +3588,8 @@ 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, @@ -4224,7 +4225,8 @@ int f2fs_write_inline_data(struct inode *inode, struct folio *folio); 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 cbd2a0d34804..3e3c35d4c98b 100644 --- a/fs/f2fs/inline.c +++ b/fs/f2fs/inline.c @@ -352,7 +352,8 @@ 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; @@ -369,7 +370,7 @@ 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);
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