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authorDarrick J. Wong <darrick.wong@oracle.com>2018-10-30 10:41:49 +1100
committerDave Chinner <david@fromorbit.com>2018-10-30 10:41:49 +1100
commit42ec3d4c02187a18e27ff94b409ec27234bf2ffd (patch)
treec9db04db8187c370718a43e6067af0e5aa944500 /fs/btrfs/ioctl.c
parent8dde90bca6fca3736ea20109654bcf6dcf2ecf1d (diff)
vfs: make remap_file_range functions take and return bytes completed
Change the remap_file_range functions to take a number of bytes to operate upon and return the number of bytes they operated on. This is a requirement for allowing fs implementations to return short clone/dedupe results to the user, which will enable us to obey resource limits in a graceful manner. A subsequent patch will enable copy_file_range to signal to the ->clone_file_range implementation that it can handle a short length, which will be returned in the function's return value. For now the short return is not implemented anywhere so the behavior won't change -- either copy_file_range manages to clone the entire range or it tries an alternative. Neither clone ioctl can take advantage of this, alas. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
Diffstat (limited to 'fs/btrfs/ioctl.c')
-rw-r--r--fs/btrfs/ioctl.c13
1 files changed, 8 insertions, 5 deletions
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index bfd99c66723e..b0c513e10977 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -4328,10 +4328,12 @@ out_unlock:
return ret;
}
-int btrfs_remap_file_range(struct file *src_file, loff_t off,
- struct file *dst_file, loff_t destoff, u64 len,
+loff_t btrfs_remap_file_range(struct file *src_file, loff_t off,
+ struct file *dst_file, loff_t destoff, loff_t len,
unsigned int remap_flags)
{
+ int ret;
+
if (remap_flags & ~(REMAP_FILE_DEDUP | REMAP_FILE_ADVISORY))
return -EINVAL;
@@ -4349,10 +4351,11 @@ int btrfs_remap_file_range(struct file *src_file, loff_t off,
return -EINVAL;
}
- return btrfs_extent_same(src, off, len, dst, destoff);
+ ret = btrfs_extent_same(src, off, len, dst, destoff);
+ } else {
+ ret = btrfs_clone_files(dst_file, src_file, off, len, destoff);
}
-
- return btrfs_clone_files(dst_file, src_file, off, len, destoff);
+ return ret < 0 ? ret : len;
}
static long btrfs_ioctl_default_subvol(struct file *file, void __user *argp)