diff options
| author | Jens Axboe <axboe@kernel.dk> | 2017-06-16 10:46:26 -0600 |
|---|---|---|
| committer | Jens Axboe <axboe@fb.com> | 2017-06-17 13:54:16 -0600 |
| commit | b610abd212c30234156bce75ea66d2b9efbbb440 (patch) | |
| tree | e8adf26ffe0833aa50845d7a906ed535b04770d3 | |
| parent | 6e001309d91902c1749455327c7aedd4ab6c11a0 (diff) | |
fs: add support for allowing applications to pass in write life time hints
Add four flags for the pwritev2(2) system call, allowing an application
to give the kernel a hint about what on-media life times can be
expected from a given write.
The intent is for these values to be relative to each other, no
absolute meaning should be attached to these flag names.
Set aside 3 bits in the iocb flags structure to carry this information
over from the pwritev2 RWF_WRITE_LIFE_* flags.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
| -rw-r--r-- | fs/read_write.c | 12 | ||||
| -rw-r--r-- | include/linux/fs.h | 12 | ||||
| -rw-r--r-- | include/uapi/linux/fs.h | 10 |
3 files changed, 33 insertions, 1 deletions
diff --git a/fs/read_write.c b/fs/read_write.c index 19d4d88fa285..975fe1d46a59 100644 --- a/fs/read_write.c +++ b/fs/read_write.c @@ -675,10 +675,11 @@ EXPORT_SYMBOL(iov_shorten); static ssize_t do_iter_readv_writev(struct file *filp, struct iov_iter *iter, loff_t *ppos, int type, int flags) { + struct inode *inode = file_inode(filp); struct kiocb kiocb; ssize_t ret; - if (flags & ~(RWF_HIPRI | RWF_DSYNC | RWF_SYNC)) + if (flags & ~(RWF_HIPRI | RWF_DSYNC | RWF_SYNC | RWF_WRITE_LIFE_MASK)) return -EOPNOTSUPP; init_sync_kiocb(&kiocb, filp); @@ -688,6 +689,15 @@ static ssize_t do_iter_readv_writev(struct file *filp, struct iov_iter *iter, kiocb.ki_flags |= IOCB_DSYNC; if (flags & RWF_SYNC) kiocb.ki_flags |= (IOCB_DSYNC | IOCB_SYNC); + if ((flags & RWF_WRITE_LIFE_MASK) || + mask_to_write_hint(inode->i_flags, S_WRITE_LIFE_SHIFT)) { + enum rw_hint hint; + + hint = mask_to_write_hint(flags, RWF_WRITE_LIFE_SHIFT); + + inode_set_write_hint(inode, hint); + kiocb.ki_flags |= write_hint_to_mask(hint, IOCB_WRITE_LIFE_SHIFT); + } kiocb.ki_pos = *ppos; if (type == READ) diff --git a/include/linux/fs.h b/include/linux/fs.h index 472c83156606..a024b32259bf 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -269,6 +269,12 @@ struct writeback_control; #define IOCB_SYNC (1 << 5) #define IOCB_WRITE (1 << 6) +/* + * Steal 3 bits for stream information, this allows 8 valid streams + */ +#define IOCB_WRITE_LIFE_SHIFT 7 +#define IOCB_WRITE_LIFE_MASK (BIT(7) | BIT(8) | BIT(9)) + struct kiocb { struct file *ki_filp; loff_t ki_pos; @@ -292,6 +298,12 @@ static inline void init_sync_kiocb(struct kiocb *kiocb, struct file *filp) }; } +static inline int iocb_write_hint(const struct kiocb *iocb) +{ + return (iocb->ki_flags & IOCB_WRITE_LIFE_MASK) >> + IOCB_WRITE_LIFE_SHIFT; +} + /* * "descriptor" for what we're up to with a read. * This allows us to use the same read code yet diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h index 8fb3b5a6e1ec..0d9d331d3b61 100644 --- a/include/uapi/linux/fs.h +++ b/include/uapi/linux/fs.h @@ -374,4 +374,14 @@ enum rw_hint { #define RWF_DSYNC 0x00000002 /* per-IO O_DSYNC */ #define RWF_SYNC 0x00000004 /* per-IO O_SYNC */ +/* + * Data life time write flags, steal 3 bits for that + */ +#define RWF_WRITE_LIFE_SHIFT 4 +#define RWF_WRITE_LIFE_MASK 0x00000070 /* 3 bits of write hints */ +#define RWF_WRITE_LIFE_SHORT (WRITE_LIFE_SHORT << RWF_WRITE_LIFE_SHIFT) +#define RWF_WRITE_LIFE_MEDIUM (WRITE_LIFE_MEDIUM << RWF_WRITE_LIFE_SHIFT) +#define RWF_WRITE_LIFE_LONG (WRITE_LIFE_LONG << RWF_WRITE_LIFE_SHIFT) +#define RWF_WRITE_LIFE_EXTREME (WRITE_LIFE_EXTREME << RWF_WRITE_LIFE_SHIFT) + #endif /* _UAPI_LINUX_FS_H */ |