On 26/05/24 09:02AM, Dave Chinner wrote:
On Mon, May 20, 2024 at 03:50:18PM +0530, Nitesh Shetty wrote:
From: Anuj Gupta <[email protected]>
This is a prep patch. Allow copy_file_range to work for block devices.
Relaxing generic_copy_file_checks allows us to reuse the existing infra,
instead of adding a new user interface for block copy offload.
Change generic_copy_file_checks to use ->f_mapping->host for both inode_in
and inode_out. Allow block device in generic_file_rw_checks.
Reviewed-by: Hannes Reinecke <[email protected]>
Signed-off-by: Anuj Gupta <[email protected]>
Signed-off-by: Nitesh Shetty <[email protected]>
---
fs/read_write.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/fs/read_write.c b/fs/read_write.c
index ef6339391351..31645ca5ed58 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -1413,8 +1413,8 @@ static int generic_copy_file_checks(struct file *file_in,
loff_t pos_in,
struct file *file_out, loff_t pos_out,
size_t *req_count, unsigned int flags)
{
- struct inode *inode_in = file_inode(file_in);
- struct inode *inode_out = file_inode(file_out);
+ struct inode *inode_in = file_in->f_mapping->host;
+ struct inode *inode_out = file_out->f_mapping->host;
uint64_t count = *req_count;
loff_t size_in;
int ret;
Ok, so this changes from file->f_inode to file->mapping->host. No
doubt this is because of how bdev inode mappings are munged.
However, the first code that is run here is:
ret = generic_file_rw_checks(file_in, file_out);
and that function still uses file_inode().
Hence there checks:
@@ -1726,7 +1726,9 @@ int generic_file_rw_checks(struct file *file_in, struct
file *file_out)
/* Don't copy dirs, pipes, sockets... */
if (S_ISDIR(inode_in->i_mode) || S_ISDIR(inode_out->i_mode))
return -EISDIR;
- if (!S_ISREG(inode_in->i_mode) || !S_ISREG(inode_out->i_mode))
+ if (!S_ISREG(inode_in->i_mode) && !S_ISBLK(inode_in->i_mode))
+ return -EINVAL;
+ if ((inode_in->i_mode & S_IFMT) != (inode_out->i_mode & S_IFMT))
return -EINVAL;
.... are being done on different inodes to the rest of
generic_copy_file_checks() when block devices are used.
Is this correct? If so, this needs a pair of comments (one for each
function) to explain why the specific inode used for these functions
is correct for block devices....
We were getting wrong size with file_inode() for block device, but we
missed to do it here in generic_file_rw_checks.
We will change the generic_file_rw_checks to use file->mapping->host
to make it consistent.
Thank You,
Nitesh Shetty
