}
EXPORT_SYMBOL(read_cache_page_gfp);
+/*
+ * Don't operate on ranges the page cache doesn't support, and don't exceed the
+ * LFS limits. If pos is under the limit it becomes a short access. If it
+ * exceeds the limit we return -EFBIG.
+ */
+static int generic_access_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;
+
+ if (!(file->f_flags & O_LARGEFILE))
+ max_size = MAX_NON_LFS;
+
+ if (unlikely(pos >= max_size))
+ return -EFBIG;
+ *count = min(*count, max_size - pos);
+ return 0;
+}
+
+static int generic_write_check_limits(struct file *file, loff_t pos,
+ loff_t *count)
+{
+ loff_t limit = rlimit(RLIMIT_FSIZE);
+
+ if (limit != RLIM_INFINITY) {
+ if (pos >= limit) {
+ send_sig(SIGXFSZ, current, 0);
+ return -EFBIG;
+ }
+ *count = min(*count, limit - pos);
+ }
+
+ return generic_access_check_limits(file, pos, count);
+}
+
/*
* Performs necessary checks before doing a write
*
{
struct file *file = iocb->ki_filp;
struct inode *inode = file->f_mapping->host;
- unsigned long limit = rlimit(RLIMIT_FSIZE);
- loff_t pos;
+ loff_t count;
+ int ret;
if (!iov_iter_count(from))
return 0;
if (iocb->ki_flags & IOCB_APPEND)
iocb->ki_pos = i_size_read(inode);
- pos = iocb->ki_pos;
-
if ((iocb->ki_flags & IOCB_NOWAIT) && !(iocb->ki_flags & IOCB_DIRECT))
return -EINVAL;
- if (limit != RLIM_INFINITY) {
- if (iocb->ki_pos >= limit) {
- send_sig(SIGXFSZ, current, 0);
- return -EFBIG;
- }
- iov_iter_truncate(from, limit - (unsigned long)pos);
- }
+ count = iov_iter_count(from);
+ ret = generic_write_check_limits(file, iocb->ki_pos, &count);
+ if (ret)
+ return ret;
+
+ iov_iter_truncate(from, count);
+ return iov_iter_count(from);
+}
+EXPORT_SYMBOL(generic_write_checks);
+
+/*
+ * Performs necessary checks before doing a clone.
+ *
+ * Can adjust amount of bytes to clone.
+ * 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_access_check_limits(file_in, pos_in, &count);
+ if (ret)
+ return ret;
+
+ ret = generic_write_check_limits(file_out, pos_out, &count);
+ if (ret)
+ return ret;
/*
- * LFS rule
+ * 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 (unlikely(pos + iov_iter_count(from) > MAX_NON_LFS &&
- !(file->f_flags & O_LARGEFILE))) {
- if (pos >= MAX_NON_LFS)
- return -EFBIG;
- iov_iter_truncate(from, MAX_NON_LFS - (unsigned long)pos);
+ 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;
+
/*
- * Are we about to exceed the fs block limit ?
- *
- * If we have written data it becomes a short write. If we have
- * exceeded without writing data we send a signal and return EFBIG.
- * Linus frestrict idea will clean these up nicely..
+ * We shortened the request but the caller can't deal with that, so
+ * bounce the request back to userspace.
*/
- if (unlikely(pos >= inode->i_sb->s_maxbytes))
- return -EFBIG;
+ if (*req_count != count && !(remap_flags & REMAP_FILE_CAN_SHORTEN))
+ return -EINVAL;
- iov_iter_truncate(from, inode->i_sb->s_maxbytes - pos);
- return iov_iter_count(from);
+ *req_count = count;
+ return 0;
}
-EXPORT_SYMBOL(generic_write_checks);
int pagecache_write_begin(struct file *file, struct address_space *mapping,
loff_t pos, unsigned len, unsigned flags,
projects / mirror_ubuntu-jammy-kernel.git / blobdiff