On Wed, 4 Aug 2010, Dmitry Monakhov wrote:
> Lukas Czerner <lczerner@xxxxxxxxxx> writes:
>
> > Adds an filesystem independent ioctl to allow implementation of file
> > system batched discard support.
> >
> > Signed-off-by: Lukas Czerner <lczerner@xxxxxxxxxx>
> > ---
> > fs/ioctl.c | 31 +++++++++++++++++++++++++++++++
> > include/linux/fs.h | 2 ++
> > 2 files changed, 33 insertions(+), 0 deletions(-)
> >
> > diff --git a/fs/ioctl.c b/fs/ioctl.c
> > index 2d140a7..6c01c3c 100644
> > --- a/fs/ioctl.c
> > +++ b/fs/ioctl.c
> > @@ -540,6 +540,33 @@ static int ioctl_fsthaw(struct file *filp)
> > return thaw_super(sb);
> > }
> >
> > +static int ioctl_fstrim(struct file *filp, unsigned long arg)
> BTW why do we have to trim fs in one shot ?
> IMHO it is much suitable to provide start,len parameters as we
> do in most functions(truncate, bdevdiscard, getdents).
> It allow userspace caller to implement a fancy looking progress bars.
Hi,
do you think it is really needed when even with todays SSD's it takes
just a couple of seconds ? And I suppose it will improve in future. But
generally I think we can do that..I would like to hear some more
opinions before I start looking at this.
Thanks.
-Lukas.
> > +{
> > + struct super_block *sb = filp->f_path.dentry->d_inode->i_sb;
> > + unsigned int minlen;
> > + int err;
> > +
> > + if (!capable(CAP_SYS_ADMIN))
> > + return -EPERM;
> > +
> > + /* If filesystem doesn't support trim feature, return. */
> > + if (sb->s_op->trim_fs == NULL)
> > + return -EOPNOTSUPP;
> > +
> > + /* If a blockdevice-backed filesystem isn't specified, return EINVAL. */
> > + if (sb->s_bdev == NULL)
> > + return -EINVAL;
> > +
> > + err = get_user(minlen, (unsigned int __user *) arg);
> > + if (err)
> > + return err;
> > +
> > + err = sb->s_op->trim_fs(minlen, sb);
> > + if (err)
> > + return err;
> > + return 0;
> > +}
> > +
> > /*
> > * When you add any new common ioctls to the switches above and below
> > * please update compat_sys_ioctl() too.
> > @@ -590,6 +617,10 @@ int do_vfs_ioctl(struct file *filp, unsigned int fd, unsigned int cmd,
> > error = ioctl_fsthaw(filp);
> > break;
> >
> > + case FITRIM:
> > + error = ioctl_fstrim(filp, arg);
> > + break;
> > +
> > case FS_IOC_FIEMAP:
> > return ioctl_fiemap(filp, arg);
> >
> > diff --git a/include/linux/fs.h b/include/linux/fs.h
> > index 68ca1b0..01632e4 100644
> > --- a/include/linux/fs.h
> > +++ b/include/linux/fs.h
> > @@ -315,6 +315,7 @@ struct inodes_stat_t {
> > #define FIGETBSZ _IO(0x00,2) /* get the block size used for bmap */
> > #define FIFREEZE _IOWR('X', 119, int) /* Freeze */
> > #define FITHAW _IOWR('X', 120, int) /* Thaw */
> > +#define FITRIM _IOWR('X', 121, int) /* Trim */
> >
> > #define FS_IOC_GETFLAGS _IOR('f', 1, long)
> > #define FS_IOC_SETFLAGS _IOW('f', 2, long)
> > @@ -1580,6 +1581,7 @@ struct super_operations {
> > ssize_t (*quota_write)(struct super_block *, int, const char *, size_t, loff_t);
> > #endif
> > int (*bdev_try_to_free_page)(struct super_block*, struct page*, gfp_t);
> > + int (*trim_fs) (unsigned int, struct super_block *);
> > };
> >
> > /*
> --
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