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Subject[RFC PATCH 01/35] vfs: clean up dedup
Date
Extract vfs_dedupe_file_range_one() helper to deal with a single dedup
request.

Export this helper to modules, so it can be used by overlayfs to stack the
dedupe method.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
---
fs/read_write.c | 90 ++++++++++++++++++++++++++++++------------------------
include/linux/fs.h | 3 ++
2 files changed, 53 insertions(+), 40 deletions(-)

diff --git a/fs/read_write.c b/fs/read_write.c
index f8547b82dfb3..82aa0d32d0cd 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -1937,6 +1937,44 @@ int vfs_dedupe_file_range_compare(struct inode *src, loff_t srcoff,
}
EXPORT_SYMBOL(vfs_dedupe_file_range_compare);

+ssize_t vfs_dedupe_file_range_one(struct file *src_file, u64 src_pos, u64 len,
+ struct file *dst_file, u64 dst_pos)
+{
+ ssize_t ret;
+
+ ret = mnt_want_write_file(dst_file);
+ if (ret)
+ return ret;
+
+ ret = clone_verify_area(dst_file, dst_pos, len, true);
+ if (ret < 0)
+ goto out_drop_write;
+
+ ret = -EINVAL;
+ if (!(capable(CAP_SYS_ADMIN) || (dst_file->f_mode & FMODE_WRITE)))
+ goto out_drop_write;
+
+ ret = -EXDEV;
+ if (src_file->f_path.mnt != dst_file->f_path.mnt)
+ goto out_drop_write;
+
+ ret = -EISDIR;
+ if (S_ISDIR(file_inode(dst_file)->i_mode))
+ goto out_drop_write;
+
+ ret = -EINVAL;
+ if (!dst_file->f_op->dedupe_file_range)
+ goto out_drop_write;
+
+ ret = dst_file->f_op->dedupe_file_range(src_file, src_pos, len,
+ dst_file, dst_pos);
+out_drop_write:
+ mnt_drop_write_file(dst_file);
+
+ return ret;
+}
+EXPORT_SYMBOL(vfs_dedupe_file_range_one);
+
int vfs_dedupe_file_range(struct file *file, struct file_dedupe_range *same)
{
struct file_dedupe_range_info *info;
@@ -1945,10 +1983,7 @@ int vfs_dedupe_file_range(struct file *file, struct file_dedupe_range *same)
u64 len;
int i;
int ret;
- bool is_admin = capable(CAP_SYS_ADMIN);
u16 count = same->dest_count;
- struct file *dst_file;
- loff_t dst_off;
ssize_t deduped;

if (!(file->f_mode & FMODE_READ))
@@ -1983,54 +2018,29 @@ int vfs_dedupe_file_range(struct file *file, struct file_dedupe_range *same)
}

for (i = 0, info = same->info; i < count; i++, info++) {
- struct inode *dst;
struct fd dst_fd = fdget(info->dest_fd);
+ struct file *dst_file = dst_fd.file;

- dst_file = dst_fd.file;
if (!dst_file) {
info->status = -EBADF;
goto next_loop;
}
- dst = file_inode(dst_file);
-
- ret = mnt_want_write_file(dst_file);
- if (ret) {
- info->status = ret;
- goto next_loop;
- }
-
- dst_off = info->dest_offset;
- ret = clone_verify_area(dst_file, dst_off, len, true);
- if (ret < 0) {
- info->status = ret;
- goto next_file;
- }
- ret = 0;

if (info->reserved) {
info->status = -EINVAL;
- } else if (!(is_admin || (dst_file->f_mode & FMODE_WRITE))) {
- info->status = -EINVAL;
- } else if (file->f_path.mnt != dst_file->f_path.mnt) {
- info->status = -EXDEV;
- } else if (S_ISDIR(dst->i_mode)) {
- info->status = -EISDIR;
- } else if (dst_file->f_op->dedupe_file_range == NULL) {
- info->status = -EINVAL;
- } else {
- deduped = dst_file->f_op->dedupe_file_range(file, off,
- len, dst_file,
- info->dest_offset);
- if (deduped == -EBADE)
- info->status = FILE_DEDUPE_RANGE_DIFFERS;
- else if (deduped < 0)
- info->status = deduped;
- else
- info->bytes_deduped += deduped;
+ goto next_loop;
}

-next_file:
- mnt_drop_write_file(dst_file);
+ deduped = vfs_dedupe_file_range_one(file, off, len,
+ dst_file,
+ info->dest_offset);
+ if (deduped == -EBADE)
+ info->status = FILE_DEDUPE_RANGE_DIFFERS;
+ else if (deduped < 0)
+ info->status = deduped;
+ else
+ info->bytes_deduped += deduped;
+
next_loop:
fdput(dst_fd);

diff --git a/include/linux/fs.h b/include/linux/fs.h
index c6baf767619e..f0f87f2beb79 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1809,6 +1809,9 @@ extern int vfs_dedupe_file_range_compare(struct inode *src, loff_t srcoff,
loff_t len, bool *is_same);
extern int vfs_dedupe_file_range(struct file *file,
struct file_dedupe_range *same);
+extern ssize_t vfs_dedupe_file_range_one(struct file *src_file, u64 src_pos,
+ u64 len, struct file *dst_file,
+ u64 dst_pos);

struct super_operations {
struct inode *(*alloc_inode)(struct super_block *sb);
--
2.14.3
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