[PATCH] f2fs: another way to set large folio by remembering inode number

[Jaegeuk Kim <jaegeuk@kernel.org>]

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. open()
 -> f2fs_iget() with large folio
4. open(WRITE), mkwrite on mmap, chmod(WRITE)
 -> return error
5. iput() and open()
 -> goto #3
6. unlink
 -> deregister the inode number

Suggested-by: Akilesh Kailash <akailash@google.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
---
 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 ++++++
 8 files changed, 75 insertions(+), 8 deletions(-)

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..f12fb1ccc877 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(F2FS_I_SB(inode),
+				    inode->i_ino, LARGE_FOLIO_INO))
+		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