From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6E119146588; Wed, 15 Apr 2026 16:41:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776271287; cv=none; b=B5AOc1h+L1pohpQDQHYmIQq0I0pX/Vj8pbHu2rOWNIJiml/DfcFkykXSSA08bHybFrZjfLoukBSz9fOQbJXCg4jk+hZgCa9q/qr1rAUVlIdvi5cKQWYiHZ+/J7yewskyNvevnwLqJtPlJzLkbe+ilm45AN46l9bVXiARnCBrFoo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776271287; c=relaxed/simple; bh=8PyWfhf5jKxbPEaTkHRaJjhCm+jjT1zRa1WHAxHshc4=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Mc31pfGyclUlZiRmbte8tomlS7BDbahS0ROMaztms1bpebsa4T+St1SQ600Ptqqn54VKA0CWjr82PPuGqGmSKdEyyba4R74f4Joz/Ie+BE7eepG19vCKD7OXeBY+ZEPHF5fG6afL5skVfKg+HU8avn+dUOh/ymxXOthfFIeMdgw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=l1wV/5MU; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="l1wV/5MU" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D42CDC19424; Wed, 15 Apr 2026 16:41:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1776271287; bh=8PyWfhf5jKxbPEaTkHRaJjhCm+jjT1zRa1WHAxHshc4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=l1wV/5MUv1b+uh7ToOiyIK5avt4BRTacFCJAI3ur2q7BKWYoZC+e3BTFSfIb2y6tW GTzHjhZ9LHHQFYgOBp8Y8bpsH3kSxYpwbHCqNFIzt5DSGGTYhKNYzyygNj4mXSS4bX ON6J4QUsg9pO+CZWNNZtkjr8VDDXA2kcP9cik4wPUUnAl/GI6JrZ4lQVoTF0lM8aWc hAPTFZBi8GWwShaColJM7zd7wlwyH/UoeDGF2DydvbftjjdAYphJz1ZkJCjGnpUy3J KpxzP3NbROtd8ZxtGgJE6EbTISHhuTlC171X4Jndnvm/rZstIiv0zcQEfH63RPssDb mTMfEvi1RTH1Q== Date: Wed, 15 Apr 2026 16:41:25 +0000 From: Jaegeuk Kim To: linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-api@vger.kernel.org, linux-fsdevel@vger.kernel.org Cc: Akilesh Kailash Subject: Re: [PATCH v2] f2fs: another way to set large folio by remembering inode number Message-ID: References: <20260409134538.3692605-1-jaegeuk@kernel.org> Precedence: bulk X-Mailing-List: linux-api@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: By the way, is it worth to add some generic apis such as 1) reclaim a specifc inode object when closing the last file 2) add another fadvise hint for large folio On 04/10, Jaegeuk Kim wrote: > enum { > F2FS_XATTR_FADV_LARGEFOLIO, > }; > > unsigned int value = BIT(F2FS_XATTR_FADV_LARGEFOLIO); > > 1. setxattr(file, "user.fadvise", &value, sizeof(unsigned int), 0) > -> register the inode number for large folio > 2. chmod(0400, file) > -> make Read-Only > 3. fsync() && close() && open(READ) > -> f2fs_iget() with large folio > 4. open(WRITE), mkwrite on mmap, chmod(WRITE) > -> return error > 5. close() and open() > -> goto #3 > 6. unlink > -> deregister the inode number > > Suggested-by: Akilesh Kailash > Signed-off-by: Jaegeuk Kim > --- > > Log from v1: > - add a condition in f2fs_drop_inode > - add Doc > > Documentation/filesystems/f2fs.rst | 41 ++++++++++++++++++++++++++---- > fs/f2fs/checkpoint.c | 2 +- > fs/f2fs/data.c | 2 +- > fs/f2fs/f2fs.h | 1 + > fs/f2fs/file.c | 11 ++++++-- > fs/f2fs/inode.c | 19 +++++++++++--- > fs/f2fs/super.c | 7 +++++ > fs/f2fs/xattr.c | 35 ++++++++++++++++++++++++- > fs/f2fs/xattr.h | 6 +++++ > 9 files changed, 111 insertions(+), 13 deletions(-) > > diff --git a/Documentation/filesystems/f2fs.rst b/Documentation/filesystems/f2fs.rst > index 7e4031631286..de899d0d3088 100644 > --- a/Documentation/filesystems/f2fs.rst > +++ b/Documentation/filesystems/f2fs.rst > @@ -1044,11 +1044,14 @@ page allocation for significant performance gains. To minimize code complexity, > this support is currently excluded from the write path, which requires handling > complex optimizations such as compression and block allocation modes. > > -This optional feature is triggered only when a file's immutable bit is set. > -Consequently, F2FS will return EOPNOTSUPP if a user attempts to open a cached > -file with write permissions, even immediately after clearing the bit. Write > -access is only restored once the cached inode is dropped. The usage flow is > -demonstrated below: > +This optional feature is triggered by two mechanisms: the file's immutable bit > +or a specific xattr flag. In both cases, F2FS ensures data integrity by > +restricting the file to a read-only state while large folios are active. > + > +1. Immutable Bit Approach: > +Triggered when the FS_IMMUTABLE_FL is set. This is a strict enforcement > +where the file cannot be modified at all until the bit is cleared and > +the cached inode is dropped. > > .. code-block:: > > @@ -1078,3 +1081,31 @@ demonstrated below: > Written 4096 bytes with pattern = zero, total_time = 29 us, max_latency = 28 us > > # rm /data/testfile_read_seq > + > +2. XATTR fadvise Approach: > +A more flexible registration via extended attributes. > + > +.. code-block:: > + > + enum { > + F2FS_XATTR_FADV_LARGEFOLIO, > + }; > + unsigned int value = BIT(F2FS_XATTR_FADV_LARGEFOLIO); > + > + /* Registers the inode number for large folio support in the subsystem.*/ > + # setxattr(file, "user.fadvise", &value, sizeof(unsigned int), 0) > + > + /* The file must be made Read-Only to transition into the large folio path. */ > + # fchmod(0400, fd) > + > + /* clean up dirty inode state. */ > + # fsync(fd) > + > + /* Drop the inode cache. > + # close(fd) > + > + /* f2fs_iget() instantiates the inode with large folio support.*/ > + # open() > + > + /* Returns -EOPNOTSUPP or error to protect the large folio cache.*/ > + # open(WRITE), mkwrite on mmap, or chmod(WRITE) > diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c > index 01e1ba77263e..fdd62ddc3ed6 100644 > --- a/fs/f2fs/checkpoint.c > +++ b/fs/f2fs/checkpoint.c > @@ -778,7 +778,7 @@ void f2fs_remove_ino_entry(struct f2fs_sb_info *sbi, nid_t ino, int type) > __remove_ino_entry(sbi, ino, type); > } > > -/* mode should be APPEND_INO, UPDATE_INO or TRANS_DIR_INO */ > +/* mode should be APPEND_INO, UPDATE_INO, LARGE_FOLIO_IO, or TRANS_DIR_INO */ > bool f2fs_exist_written_data(struct f2fs_sb_info *sbi, nid_t ino, int mode) > { > struct inode_management *im = &sbi->im[mode]; > diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c > index 965d4e6443c6..5e46230398d7 100644 > --- a/fs/f2fs/data.c > +++ b/fs/f2fs/data.c > @@ -2494,7 +2494,7 @@ static int f2fs_read_data_large_folio(struct inode *inode, > int ret = 0; > bool folio_in_bio; > > - if (!IS_IMMUTABLE(inode) || f2fs_compressed_file(inode)) { > + if (f2fs_compressed_file(inode)) { > if (folio) > folio_unlock(folio); > return -EOPNOTSUPP; > diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h > index e40b6b2784ee..02bc6eb96a59 100644 > --- a/fs/f2fs/f2fs.h > +++ b/fs/f2fs/f2fs.h > @@ -381,6 +381,7 @@ enum { > /* for the list of ino */ > enum { > ORPHAN_INO, /* for orphan ino list */ > + LARGE_FOLIO_INO, /* for large folio case */ > APPEND_INO, /* for append ino list */ > UPDATE_INO, /* for update ino list */ > TRANS_DIR_INO, /* for transactions dir ino list */ > diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c > index c0220cd7b332..64ba900410fc 100644 > --- a/fs/f2fs/file.c > +++ b/fs/f2fs/file.c > @@ -2068,9 +2068,16 @@ static long f2fs_fallocate(struct file *file, int mode, > > static int f2fs_release_file(struct inode *inode, struct file *filp) > { > - if (atomic_dec_and_test(&F2FS_I(inode)->open_count)) > + if (atomic_dec_and_test(&F2FS_I(inode)->open_count)) { > f2fs_remove_donate_inode(inode); > - > + /* > + * In order to get large folio as soon as possible, let's drop > + * inode cache asap. See also f2fs_drop_inode. > + */ > + if (f2fs_exist_written_data(F2FS_I_SB(inode), > + inode->i_ino, LARGE_FOLIO_INO)) > + d_drop(filp->f_path.dentry); > + } > /* > * f2fs_release_file is called at every close calls. So we should > * not drop any inmemory pages by close called by other process. > diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c > index 89240be8cc59..e100bc5a378c 100644 > --- a/fs/f2fs/inode.c > +++ b/fs/f2fs/inode.c > @@ -565,6 +565,20 @@ static bool is_meta_ino(struct f2fs_sb_info *sbi, unsigned int ino) > ino == F2FS_COMPRESS_INO(sbi); > } > > +static void f2fs_mapping_set_large_folio(struct inode *inode) > +{ > + struct f2fs_sb_info *sbi = F2FS_I_SB(inode); > + > + if (f2fs_compressed_file(inode)) > + return; > + if (f2fs_quota_file(sbi, inode->i_ino)) > + return; > + if (IS_IMMUTABLE(inode) || > + (f2fs_exist_written_data(sbi, inode->i_ino, LARGE_FOLIO_INO) && > + !(inode->i_mode & S_IWUGO))) > + mapping_set_folio_min_order(inode->i_mapping, 0); > +} > + > struct inode *f2fs_iget(struct super_block *sb, unsigned long ino) > { > struct f2fs_sb_info *sbi = F2FS_SB(sb); > @@ -620,9 +634,7 @@ struct inode *f2fs_iget(struct super_block *sb, unsigned long ino) > inode->i_op = &f2fs_file_inode_operations; > inode->i_fop = &f2fs_file_operations; > inode->i_mapping->a_ops = &f2fs_dblock_aops; > - if (IS_IMMUTABLE(inode) && !f2fs_compressed_file(inode) && > - !f2fs_quota_file(sbi, inode->i_ino)) > - mapping_set_folio_min_order(inode->i_mapping, 0); > + f2fs_mapping_set_large_folio(inode); > } else if (S_ISDIR(inode->i_mode)) { > inode->i_op = &f2fs_dir_inode_operations; > inode->i_fop = &f2fs_dir_operations; > @@ -895,6 +907,7 @@ void f2fs_evict_inode(struct inode *inode) > f2fs_remove_ino_entry(sbi, inode->i_ino, APPEND_INO); > f2fs_remove_ino_entry(sbi, inode->i_ino, UPDATE_INO); > f2fs_remove_ino_entry(sbi, inode->i_ino, FLUSH_INO); > + f2fs_remove_ino_entry(sbi, inode->i_ino, LARGE_FOLIO_INO); > > if (!is_sbi_flag_set(sbi, SBI_IS_FREEZING)) { > sb_start_intwrite(inode->i_sb); > diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c > index ccf806b676f5..11d1e0c99ac1 100644 > --- a/fs/f2fs/super.c > +++ b/fs/f2fs/super.c > @@ -1844,6 +1844,13 @@ static int f2fs_drop_inode(struct inode *inode) > return 1; > } > } > + /* > + * In order to get large folio as soon as possible, let's drop > + * inode cache asap. See also f2fs_release_file. > + */ > + if (f2fs_exist_written_data(sbi, inode->i_ino, LARGE_FOLIO_INO) && > + !is_inode_flag_set(inode, FI_DIRTY_INODE)) > + return 1; > > /* > * This is to avoid a deadlock condition like below. > diff --git a/fs/f2fs/xattr.c b/fs/f2fs/xattr.c > index 941dc62a6d6f..0c0e44c2dcdd 100644 > --- a/fs/f2fs/xattr.c > +++ b/fs/f2fs/xattr.c > @@ -44,6 +44,16 @@ static void xattr_free(struct f2fs_sb_info *sbi, void *xattr_addr, > kfree(xattr_addr); > } > > +static int f2fs_xattr_fadvise_get(struct inode *inode, void *buffer) > +{ > + if (!buffer) > + goto out; > + if (mapping_large_folio_support(inode->i_mapping)) > + *((unsigned int *)buffer) |= BIT(F2FS_XATTR_FADV_LARGEFOLIO); > +out: > + return sizeof(unsigned int); > +} > + > static int f2fs_xattr_generic_get(const struct xattr_handler *handler, > struct dentry *unused, struct inode *inode, > const char *name, void *buffer, size_t size) > @@ -61,10 +71,29 @@ static int f2fs_xattr_generic_get(const struct xattr_handler *handler, > default: > return -EINVAL; > } > + if (handler->flags == F2FS_XATTR_INDEX_USER && > + !strcmp(name, "fadvise")) > + return f2fs_xattr_fadvise_get(inode, buffer); > + > return f2fs_getxattr(inode, handler->flags, name, > buffer, size, NULL); > } > > +static int f2fs_xattr_fadvise_set(struct inode *inode, const void *value) > +{ > + unsigned int new_fadvise; > + > + new_fadvise = *(unsigned int *)value; > + > + if (new_fadvise & BIT(F2FS_XATTR_FADV_LARGEFOLIO)) > + f2fs_add_ino_entry(F2FS_I_SB(inode), > + inode->i_ino, LARGE_FOLIO_INO); > + else > + f2fs_remove_ino_entry(F2FS_I_SB(inode), > + inode->i_ino, LARGE_FOLIO_INO); > + return 0; > +} > + > static int f2fs_xattr_generic_set(const struct xattr_handler *handler, > struct mnt_idmap *idmap, > struct dentry *unused, struct inode *inode, > @@ -84,6 +113,10 @@ static int f2fs_xattr_generic_set(const struct xattr_handler *handler, > default: > return -EINVAL; > } > + if (handler->flags == F2FS_XATTR_INDEX_USER && > + !strcmp(name, "fadvise")) > + return f2fs_xattr_fadvise_set(inode, value); > + > return f2fs_setxattr(inode, handler->flags, name, > value, size, NULL, flags); > } > @@ -842,4 +875,4 @@ int __init f2fs_init_xattr_cache(void) > void f2fs_destroy_xattr_cache(void) > { > kmem_cache_destroy(inline_xattr_slab); > -} > \ No newline at end of file > +} > diff --git a/fs/f2fs/xattr.h b/fs/f2fs/xattr.h > index bce3d93e4755..455f460d014e 100644 > --- a/fs/f2fs/xattr.h > +++ b/fs/f2fs/xattr.h > @@ -24,6 +24,7 @@ > #define F2FS_XATTR_REFCOUNT_MAX 1024 > > /* Name indexes */ > +#define F2FS_USER_FADVISE_NAME "user.fadvise" > #define F2FS_SYSTEM_ADVISE_NAME "system.advise" > #define F2FS_XATTR_INDEX_USER 1 > #define F2FS_XATTR_INDEX_POSIX_ACL_ACCESS 2 > @@ -39,6 +40,11 @@ > #define F2FS_XATTR_NAME_ENCRYPTION_CONTEXT "c" > #define F2FS_XATTR_NAME_VERITY "v" > > +/* used for F2FS_USER_FADVISE_NAME */ > +enum { > + F2FS_XATTR_FADV_LARGEFOLIO, > +}; > + > struct f2fs_xattr_header { > __le32 h_magic; /* magic number for identification */ > __le32 h_refcount; /* reference count */ > -- > 2.53.0.1213.gd9a14994de-goog >