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authorLukas Czerner <lczerner@redhat.com>2010-11-22 12:29:18 +0100
committerJan Kara <jack@suse.cz>2011-01-10 19:04:05 +0100
commit9c52749232b5cef506877ac633ea14083bd17e02 (patch)
tree6e8a37d36dc648d77980c49507321d29b340c64f /fs
parentext3: Add batched discard support for ext3 (diff)
downloadlinux-dev-9c52749232b5cef506877ac633ea14083bd17e02.tar.xz
linux-dev-9c52749232b5cef506877ac633ea14083bd17e02.zip
ext3: Add FITRIM handling
The ioctl takes fstrim_range structure (defined in include/linux/fs.h) as an argument specifying a range of filesystem to trim and the minimum size of an continguous extent to trim. After the FITRIM is done, the number of bytes passed from the filesystem down the block stack to the device for potential discard is stored in fstrim_range.len. This number is a maximum discard amount from the storage device's perspective, because FITRIM called repeatedly will keep sending the same sectors for discard. fstrim_range.len will report the same potential discard bytes each time, but only sectors which had been written to between the discards would actually be discarded by the storage device. Further, the kernel block layer reserves the right to adjust the discard ranges to fit raid stripe geometry, non-trim capable devices in a LVM setup, etc. These reductions would not be reflected in fstrim_range.len. Thus fstrim_range.len can give the user better insight on how much storage space has potentially been released for wear-leveling, but it needs to be one of only one criteria the userspace tools take into account when trying to optimize calls to FITRIM. Thanks to Greg Freemyer <greg.freemyer@gmail.com> for better commit message. Signed-off-by: Lukas Czerner <lczerner@redhat.com> Signed-off-by: Jan Kara <jack@suse.cz>
Diffstat (limited to 'fs')
-rw-r--r--fs/ext3/ioctl.c22
1 files changed, 22 insertions, 0 deletions
diff --git a/fs/ext3/ioctl.c b/fs/ext3/ioctl.c
index 88974814783a..fc080dd561f7 100644
--- a/fs/ext3/ioctl.c
+++ b/fs/ext3/ioctl.c
@@ -276,7 +276,29 @@ group_add_out:
mnt_drop_write(filp->f_path.mnt);
return err;
}
+ case FITRIM: {
+ struct super_block *sb = inode->i_sb;
+ struct fstrim_range range;
+ int ret = 0;
+
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ if (copy_from_user(&range, (struct fstrim_range *)arg,
+ sizeof(range)))
+ return -EFAULT;
+
+ ret = ext3_trim_fs(sb, &range);
+ if (ret < 0)
+ return ret;
+
+ if (copy_to_user((struct fstrim_range *)arg, &range,
+ sizeof(range)))
+ return -EFAULT;
+
+ return 0;
+ }
default:
return -ENOTTY;