[PATCH v4 3/5] fcntl: add F_{SET/GET}_RW_HINT_EX
From: Kanchan Joshi <hidden>
Date: 2024-08-26 17:14:27
Also in:
linux-f2fs-devel, linux-fsdevel, linux-nvme, linux-scsi
Subsystem:
file locking (flock() and fcntl()/lockf()), filesystems (vfs and infrastructure), the rest · Maintainers:
Jeff Layton, Chuck Lever, Alexander Viro, Christian Brauner, Linus Torvalds
This is similar to existing F_{SET/GET}_RW_HINT but more
generic/extensible.
F_SET/GET_RW_HINT_EX take a pointer to a struct rw_hint_ex as argument:
struct rw_hint_ex {
__u8 type;
__u8 pad[7];
__u64 val;
};
With F_SET_RW_HINT_EX, the user passes the hint type and its value.
Hint type can be either life hint (TYPE_RW_LIFE_HINT) or placement hint
(TYPE_RW_PLACEMENT_HINT). The interface allows to add more hint types in
future.
Valid values for life hints are same as enforced by existing
fcntl(F_SET_RW_HINT).
Valid values for placement hints are between 0 to 127, both inclusive.
The inode retains either the life hint or the placement hint, whichever
is set later. The set hint type and its value can be queried by
F_GET_RW_HINT_EX.
The i_write_hint field of the inode is a 1-byte field. Use the most
significant bit as the hint type. This bit is set for placement hint.
For life hint, this bit remains zero.
Signed-off-by: Kanchan Joshi <redacted>
Signed-off-by: Nitesh Shetty <redacted>
---
fs/fcntl.c | 67 ++++++++++++++++++++++++++++++++++++++
include/linux/rw_hint.h | 13 ++++++++
include/uapi/linux/fcntl.h | 14 ++++++++
3 files changed, 94 insertions(+)
diff --git a/fs/fcntl.c b/fs/fcntl.c
index 46cf08f67278..d82fd4142104 100644
--- a/fs/fcntl.c
+++ b/fs/fcntl.c@@ -291,6 +291,14 @@ static bool rw_life_hint_valid(u64 hint) } } +static inline bool rw_placement_hint_valid(u64 val) +{ + if (val <= MAX_PLACEMENT_HINT_VAL) + return true; + + return false; +} + static long fcntl_get_rw_life_hint(struct file *file, unsigned int cmd, unsigned long arg) {
@@ -327,6 +335,59 @@ static long fcntl_set_rw_life_hint(struct file *file, unsigned int cmd, return 0; } +static long fcntl_get_rw_hint_ex(struct file *file, unsigned int cmd, + unsigned long arg) +{ + struct rw_hint_ex __user *rw_hint_ex_p = (void __user *)arg; + struct rw_hint_ex rwh = {}; + struct inode *inode = file_inode(file); + u8 hint = READ_ONCE(inode->i_write_hint); + + rwh.type = WRITE_HINT_TYPE(hint); + rwh.val = WRITE_HINT_VAL(hint); + + if (copy_to_user(rw_hint_ex_p, &rwh, sizeof(rwh))) + return -EFAULT; + + return 0; +} + +static long fcntl_set_rw_hint_ex(struct file *file, unsigned int cmd, + unsigned long arg) +{ + struct rw_hint_ex __user *rw_hint_ex_p = (void __user *)arg; + struct rw_hint_ex rwh; + struct inode *inode = file_inode(file); + u64 hint; + int i; + + if (copy_from_user(&rwh, rw_hint_ex_p, sizeof(rwh))) + return -EFAULT; + for (i = 0; i < ARRAY_SIZE(rwh.pad); i++) + if (rwh.pad[i]) + return -EINVAL; + switch (rwh.type) { + case TYPE_RW_LIFE_HINT: + if (!rw_life_hint_valid(rwh.val)) + return -EINVAL; + hint = rwh.val; + break; + case TYPE_RW_PLACEMENT_HINT: + if (!rw_placement_hint_valid(rwh.val)) + return -EINVAL; + hint = PLACEMENT_HINT_TYPE | rwh.val; + break; + default: + return -EINVAL; + } + + WRITE_ONCE(inode->i_write_hint, hint); + if (file->f_mapping->host != inode) + WRITE_ONCE(file->f_mapping->host->i_write_hint, hint); + + return 0; +} + /* Is the file descriptor a dup of the file? */ static long f_dupfd_query(int fd, struct file *filp) {
@@ -454,6 +515,12 @@ static long do_fcntl(int fd, unsigned int cmd, unsigned long arg, case F_SET_RW_HINT: err = fcntl_set_rw_life_hint(filp, cmd, arg); break; + case F_GET_RW_HINT_EX: + err = fcntl_get_rw_hint_ex(filp, cmd, arg); + break; + case F_SET_RW_HINT_EX: + err = fcntl_set_rw_hint_ex(filp, cmd, arg); + break; default: break; }
diff --git a/include/linux/rw_hint.h b/include/linux/rw_hint.h
index e17fd9fa65d4..611c51d23d96 100644
--- a/include/linux/rw_hint.h
+++ b/include/linux/rw_hint.h@@ -16,4 +16,17 @@ enum rw_life_hint { WRITE_LIFE_EXTREME = RWH_WRITE_LIFE_EXTREME, }; +#define WRITE_HINT_TYPE_BIT BIT(7) +#define WRITE_HINT_VAL_MASK (WRITE_HINT_TYPE_BIT - 1) +#define WRITE_HINT_TYPE(h) (((h) & WRITE_HINT_TYPE_BIT) ? \ + TYPE_RW_PLACEMENT_HINT : TYPE_RW_LIFE_HINT) +#define WRITE_HINT_VAL(h) ((h) & WRITE_HINT_VAL_MASK) + +#define WRITE_PLACEMENT_HINT(h) (((h) & WRITE_HINT_TYPE_BIT) ? \ + WRITE_HINT_VAL(h) : 0) +#define WRITE_LIFE_HINT(h) (((h) & WRITE_HINT_TYPE_BIT) ? \ + 0 : WRITE_HINT_VAL(h)) + +#define PLACEMENT_HINT_TYPE WRITE_HINT_TYPE_BIT +#define MAX_PLACEMENT_HINT_VAL WRITE_HINT_VAL_MASK #endif /* _LINUX_RW_HINT_H */
diff --git a/include/uapi/linux/fcntl.h b/include/uapi/linux/fcntl.h
index c0bcc185fa48..dfe77fa86776 100644
--- a/include/uapi/linux/fcntl.h
+++ b/include/uapi/linux/fcntl.h@@ -57,6 +57,8 @@ #define F_SET_RW_HINT (F_LINUX_SPECIFIC_BASE + 12) #define F_GET_FILE_RW_HINT (F_LINUX_SPECIFIC_BASE + 13) #define F_SET_FILE_RW_HINT (F_LINUX_SPECIFIC_BASE + 14) +#define F_GET_RW_HINT_EX (F_LINUX_SPECIFIC_BASE + 15) +#define F_SET_RW_HINT_EX (F_LINUX_SPECIFIC_BASE + 16) /* * Valid hint values for F_{GET,SET}_RW_HINT. 0 is "not set", or can be
@@ -76,6 +78,18 @@ */ #define RWF_WRITE_LIFE_NOT_SET RWH_WRITE_LIFE_NOT_SET +enum rw_hint_type { + TYPE_RW_LIFE_HINT, + TYPE_RW_PLACEMENT_HINT +}; + +/* Exchange information with F_{GET/SET}_RW_HINT fcntl */ +struct rw_hint_ex { + __u8 type; + __u8 pad[7]; + __u64 val; +}; + /* * Types of directory notifications that may be requested. */
--
2.25.1