This patch adds a function which can be used to read fragments in the
readahead call.
This function is necessary because filesystems built with the -tailends
(or -always-use-fragments) option may have fragments present which
cannot be currently handled.
Signed-off-by: Phillip Lougher <phillip@xxxxxxxxxxxxxxx>
---
fs/squashfs/file.c | 35 +++++++++++++++++++++++++++++++++++
1 file changed, 35 insertions(+)
diff --git a/fs/squashfs/file.c b/fs/squashfs/file.c
index f0c64ee272d5..3a4cce16d7da 100644
--- a/fs/squashfs/file.c
+++ b/fs/squashfs/file.c
@@ -497,6 +497,41 @@ static int squashfs_read_folio(struct file *file, struct folio *folio)
return res;
}
+static unsigned int squashfs_readahead_fragment(struct page **page,
+ unsigned int pages, unsigned int expected)
+{
+ struct inode *inode = page[0]->mapping->host;
+ struct squashfs_cache_entry *buffer = squashfs_get_fragment(inode->i_sb,
+ squashfs_i(inode)->fragment_block,
+ squashfs_i(inode)->fragment_size);
+ struct squashfs_sb_info *msblk = inode->i_sb->s_fs_info;
+ unsigned int n, mask = (1 << (msblk->block_log - PAGE_SHIFT)) - 1;
+
+ if (buffer->error)
+ goto out;
+
+ expected += squashfs_i(inode)->fragment_offset;
+
+ for (n = 0; n < pages; n++) {
+ unsigned int base = (page[n]->index & mask) << PAGE_SHIFT;
+ unsigned int offset = base + squashfs_i(inode)->fragment_offset;
+
+ if (expected > offset) {
+ unsigned int avail = min_t(unsigned int, expected -
+ offset, PAGE_SIZE);
+
+ squashfs_fill_page(page[n], buffer, offset, avail);
+ }
+
+ unlock_page(page[n]);
+ put_page(page[n]);
+ }
+
+out:
+ squashfs_cache_put(buffer);
+ return buffer->error;
+}
+
static void squashfs_readahead(struct readahead_control *ractl)
{
struct inode *inode = ractl->mapping->host;
--
2.34.1
