On Fri, Dec 20, 2024 at 5:25 AM Chao Yu <c...@kernel.org> wrote: > > 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 >
I understand your point and I will revise it accordingly. > 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); > >> > _______________________________________________ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel