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authorAnna Schumaker <Anna.Schumaker@netapp.com>2015-11-11 00:53:33 +0300
committerAl Viro <viro@zeniv.linux.org.uk>2015-12-01 22:00:55 +0300
commiteac70053a141998c40907747d6cea1d53a9414be (patch)
tree67b51897837e7e031727afd38596e9d5eb10e196 /fs/read_write.c
parent3db11b2eecc02dc0eee943e71822c6d929281aa7 (diff)
downloadlinux-eac70053a141998c40907747d6cea1d53a9414be.tar.xz
vfs: Add vfs_copy_file_range() support for pagecache copies
This allows us to have an in-kernel copy mechanism that avoids frequent switches between kernel and user space. This is especially useful so NFSD can support server-side copies. The default (flags=0) means to first attempt copy acceleration, but use the pagecache if that fails. Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Padraig Brady <P@draigBrady.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/read_write.c')
-rw-r--r--fs/read_write.c13
1 files changed, 9 insertions, 4 deletions
diff --git a/fs/read_write.c b/fs/read_write.c
index 173140029a7a..c81ef394a3d4 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -1354,8 +1354,7 @@ ssize_t vfs_copy_file_range(struct file *file_in, loff_t pos_in,
if (!(file_in->f_mode & FMODE_READ) ||
!(file_out->f_mode & FMODE_WRITE) ||
- (file_out->f_flags & O_APPEND) ||
- !file_out->f_op->copy_file_range)
+ (file_out->f_flags & O_APPEND))
return -EBADF;
/* this could be relaxed once a method supports cross-fs copies */
@@ -1369,8 +1368,14 @@ ssize_t vfs_copy_file_range(struct file *file_in, loff_t pos_in,
if (ret)
return ret;
- ret = file_out->f_op->copy_file_range(file_in, pos_in, file_out, pos_out,
- len, flags);
+ ret = -EOPNOTSUPP;
+ if (file_out->f_op->copy_file_range)
+ ret = file_out->f_op->copy_file_range(file_in, pos_in, file_out,
+ pos_out, len, flags);
+ if (ret == -EOPNOTSUPP)
+ ret = do_splice_direct(file_in, &pos_in, file_out, &pos_out,
+ len > MAX_RW_COUNT ? MAX_RW_COUNT : len, 0);
+
if (ret > 0) {
fsnotify_access(file_in);
add_rchar(current, ret);