From: Murphy Zhou jencce.kernel@gmail.com
Now overlayfs falls back to use default file splice read and write, which is not compatiple with overlayfs, returning EFAULT. xfstests generic/591 can reproduce part of this.
Tested this patch with xfstests auto group tests.
[ Needed in 5.4 to fix a deadlock triggered via xfstests overlay/019 -- Leah Rumancik ]
Signed-off-by: Murphy Zhou jencce.kernel@gmail.com Signed-off-by: Miklos Szeredi mszeredi@redhat.com --- fs/overlayfs/file.c | 47 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 47 insertions(+)
diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c index 7a08a576f7b2..ab5e92897270 100644 --- a/fs/overlayfs/file.c +++ b/fs/overlayfs/file.c @@ -9,6 +9,9 @@ #include <linux/xattr.h> #include <linux/uio.h> #include <linux/uaccess.h> +#include <linux/splice.h> +#include <linux/mm.h> +#include <linux/fs.h> #include "overlayfs.h"
static char ovl_whatisit(struct inode *inode, struct inode *realinode) @@ -293,6 +296,48 @@ static ssize_t ovl_write_iter(struct kiocb *iocb, struct iov_iter *iter) return ret; }
+static ssize_t ovl_splice_read(struct file *in, loff_t *ppos, + struct pipe_inode_info *pipe, size_t len, + unsigned int flags) +{ + ssize_t ret; + struct fd real; + const struct cred *old_cred; + + ret = ovl_real_fdget(in, &real); + if (ret) + return ret; + + old_cred = ovl_override_creds(file_inode(in)->i_sb); + ret = generic_file_splice_read(real.file, ppos, pipe, len, flags); + revert_creds(old_cred); + + ovl_file_accessed(in); + fdput(real); + return ret; +} + +static ssize_t +ovl_splice_write(struct pipe_inode_info *pipe, struct file *out, + loff_t *ppos, size_t len, unsigned int flags) +{ + struct fd real; + const struct cred *old_cred; + ssize_t ret; + + ret = ovl_real_fdget(out, &real); + if (ret) + return ret; + + old_cred = ovl_override_creds(file_inode(out)->i_sb); + ret = iter_file_splice_write(pipe, real.file, ppos, len, flags); + revert_creds(old_cred); + + ovl_file_accessed(out); + fdput(real); + return ret; +} + static int ovl_fsync(struct file *file, loff_t start, loff_t end, int datasync) { struct fd real; @@ -649,6 +694,8 @@ const struct file_operations ovl_file_operations = { .fadvise = ovl_fadvise, .unlocked_ioctl = ovl_ioctl, .compat_ioctl = ovl_compat_ioctl, + .splice_read = ovl_splice_read, + .splice_write = ovl_splice_write,
.copy_file_range = ovl_copy_file_range, .remap_file_range = ovl_remap_file_range,