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authorDarrick J. Wong <darrick.wong@oracle.com>2020-10-14 16:47:08 -0700
committerDarrick J. Wong <darrick.wong@oracle.com>2020-10-14 16:47:08 -0700
commit02e83f46ebfaf9405881e290794c913d457541f0 (patch)
tree14f28eb39d62b05a369e01715ca771949e30d91e /mm/filemap.c
parentbbf5c979011a099af5dc76498918ed7df445635b (diff)
vfs: move generic_remap_checks out of mm
I would like to move all the generic helpers for the vfs remap range functionality (aka clonerange and dedupe) into a separate file so that they won't be scattered across the vfs and the mm subsystems. The eventual goal is to be able to deselect remap_range.c if none of the filesystems need that code, but the tricky part here is picking a stable(ish) part of the merge window to rearrange code. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Diffstat (limited to 'mm/filemap.c')
-rw-r--r--mm/filemap.c81
1 files changed, 1 insertions, 80 deletions
diff --git a/mm/filemap.c b/mm/filemap.c
index 99c49eeae71b..cf20e5aeb11b 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -3098,8 +3098,7 @@ EXPORT_SYMBOL(read_cache_page_gfp);
* LFS limits. If pos is under the limit it becomes a short access. If it
* exceeds the limit we return -EFBIG.
*/
-static int generic_write_check_limits(struct file *file, loff_t pos,
- loff_t *count)
+int generic_write_check_limits(struct file *file, loff_t pos, loff_t *count)
{
struct inode *inode = file->f_mapping->host;
loff_t max_size = inode->i_sb->s_maxbytes;
@@ -3162,84 +3161,6 @@ inline ssize_t generic_write_checks(struct kiocb *iocb, struct iov_iter *from)
EXPORT_SYMBOL(generic_write_checks);
/*
- * Performs necessary checks before doing a clone.
- *
- * Can adjust amount of bytes to clone via @req_count argument.
- * Returns appropriate error code that caller should return or
- * zero in case the clone should be allowed.
- */
-int generic_remap_checks(struct file *file_in, loff_t pos_in,
- struct file *file_out, loff_t pos_out,
- loff_t *req_count, unsigned int remap_flags)
-{
- struct inode *inode_in = file_in->f_mapping->host;
- struct inode *inode_out = file_out->f_mapping->host;
- uint64_t count = *req_count;
- uint64_t bcount;
- loff_t size_in, size_out;
- loff_t bs = inode_out->i_sb->s_blocksize;
- int ret;
-
- /* The start of both ranges must be aligned to an fs block. */
- if (!IS_ALIGNED(pos_in, bs) || !IS_ALIGNED(pos_out, bs))
- return -EINVAL;
-
- /* Ensure offsets don't wrap. */
- if (pos_in + count < pos_in || pos_out + count < pos_out)
- return -EINVAL;
-
- size_in = i_size_read(inode_in);
- size_out = i_size_read(inode_out);
-
- /* Dedupe requires both ranges to be within EOF. */
- if ((remap_flags & REMAP_FILE_DEDUP) &&
- (pos_in >= size_in || pos_in + count > size_in ||
- pos_out >= size_out || pos_out + count > size_out))
- return -EINVAL;
-
- /* Ensure the infile range is within the infile. */
- if (pos_in >= size_in)
- return -EINVAL;
- count = min(count, size_in - (uint64_t)pos_in);
-
- ret = generic_write_check_limits(file_out, pos_out, &count);
- if (ret)
- return ret;
-
- /*
- * If the user wanted us to link to the infile's EOF, round up to the
- * next block boundary for this check.
- *
- * Otherwise, make sure the count is also block-aligned, having
- * already confirmed the starting offsets' block alignment.
- */
- if (pos_in + count == size_in) {
- bcount = ALIGN(size_in, bs) - pos_in;
- } else {
- if (!IS_ALIGNED(count, bs))
- count = ALIGN_DOWN(count, bs);
- bcount = count;
- }
-
- /* Don't allow overlapped cloning within the same file. */
- if (inode_in == inode_out &&
- pos_out + bcount > pos_in &&
- pos_out < pos_in + bcount)
- return -EINVAL;
-
- /*
- * We shortened the request but the caller can't deal with that, so
- * bounce the request back to userspace.
- */
- if (*req_count != count && !(remap_flags & REMAP_FILE_CAN_SHORTEN))
- return -EINVAL;
-
- *req_count = count;
- return 0;
-}
-
-
-/*
* Performs common checks before doing a file copy/clone
* from @file_in to @file_out.
*/