[f2fs-dev] [PATCH] f2fs: separate NOCoW and pinfile semantics

[Chao Yu <chao@kernel.org>]

Pinning a file is heavy, because skipping pinned files make GC
running with heavy load or no effect.

So that this patch proposes to separate nocow and pinfile semantics:
- NOCoW flag can only be set on regular file.
- NOCoW file will only trigger IPU at common writeback/flush.
- NOCow file will do OPU during GC.

This flag can satisfying the demand of:
1) avoiding fragment of file's physical block
2) userspace doesn't want to pin file's physical address

Signed-off-by: Chao Yu <chao.yu@oppo.com>
---
 fs/f2fs/data.c |  3 ++-
 fs/f2fs/f2fs.h |  1 +
 fs/f2fs/file.c | 25 ++++++++++++++++++++++++-
 3 files changed, 27 insertions(+), 2 deletions(-)

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 54a7a8ad994d..c8eab78f7d89 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -2495,7 +2495,8 @@ bool f2fs_should_update_inplace(struct inode *inode, struct f2fs_io_info *fio)
 	if (is_inode_flag_set(inode, FI_ALIGNED_WRITE))
 		return false;
 
-	if (f2fs_is_pinned_file(inode))
+	if (f2fs_is_pinned_file(inode) ||
+			F2FS_I(inode)->i_flags & F2FS_NOCOW_FL)
 		return true;
 
 	/* if this is cold file, we should overwrite to avoid fragmentation */
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 492af5b96de1..e91ece55f5e8 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -2916,6 +2916,7 @@ static inline void f2fs_change_bit(unsigned int nr, char *addr)
 #define F2FS_NOCOMP_FL			0x00000400 /* Don't compress */
 #define F2FS_INDEX_FL			0x00001000 /* hash-indexed directory */
 #define F2FS_DIRSYNC_FL			0x00010000 /* dirsync behaviour (directories only) */
+#define F2FS_NOCOW_FL			0x00800000 /* Do not cow file */
 #define F2FS_PROJINHERIT_FL		0x20000000 /* Create with parents projid */
 #define F2FS_CASEFOLD_FL		0x40000000 /* Casefolded file */
 
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 09287876dbb7..7f92a3a157f7 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -1851,6 +1851,20 @@ static int f2fs_setflags_common(struct inode *inode, u32 iflags, u32 mask)
 	if (IS_NOQUOTA(inode))
 		return -EPERM;
 
+	if ((iflags ^ masked_flags) & F2FS_NOCOW_FL) {
+		int ret;
+
+		if (!S_ISREG(inode->i_mode))
+			return -EINVAL;
+		if (f2fs_should_update_outplace(inode, NULL))
+			return -EINVAL;
+		if (f2fs_is_pinned_file(inode))
+			return -EINVAL;
+		ret = f2fs_convert_inline_inode(inode);
+		if (ret)
+			return ret;
+	}
+
 	if ((iflags ^ masked_flags) & F2FS_CASEFOLD_FL) {
 		if (!f2fs_sb_has_casefold(F2FS_I_SB(inode)))
 			return -EOPNOTSUPP;
@@ -1926,6 +1940,7 @@ static const struct {
 	{ F2FS_NOCOMP_FL,	FS_NOCOMP_FL },
 	{ F2FS_INDEX_FL,	FS_INDEX_FL },
 	{ F2FS_DIRSYNC_FL,	FS_DIRSYNC_FL },
+	{ F2FS_NOCOW_FL,	FS_NOCOW_FL },
 	{ F2FS_PROJINHERIT_FL,	FS_PROJINHERIT_FL },
 	{ F2FS_CASEFOLD_FL,	FS_CASEFOLD_FL },
 };
@@ -1957,7 +1972,8 @@ static const struct {
 		FS_NOCOMP_FL |		\
 		FS_DIRSYNC_FL |		\
 		FS_PROJINHERIT_FL |	\
-		FS_CASEFOLD_FL)
+		FS_CASEFOLD_FL |	\
+		FS_NOCOW_FL)
 
 /* Convert f2fs on-disk i_flags to FS_IOC_{GET,SET}FLAGS flags */
 static inline u32 f2fs_iflags_to_fsflags(u32 iflags)
@@ -3081,6 +3097,13 @@ static int f2fs_ioc_set_pin_file(struct file *filp, unsigned long arg)
 
 	inode_lock(inode);
 
+	if (F2FS_I(inode)->i_flags & F2FS_NOCOW_FL) {
+		f2fs_info(F2FS_I_SB(inode), "inode (%lu) is already NOCOW one",
+			inode->i_ino);
+		ret = -EINVAL;
+		goto out;
+	}
+
 	if (!pin) {
 		clear_inode_flag(inode, FI_PIN_FILE);
 		f2fs_i_gc_failures_write(inode, 0);
-- 
2.25.1



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