Remove the restriction that inline data must start on a page boundary
in a file.  This allows, for example, the first 2KiB to be stored out
of line and the trailing 30 bytes to be stored inline.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
v2:
 - Rebase on top of iomap: Support file tail packing v9

 fs/iomap/buffered-io.c | 34 ++++++++++++++++------------------
 1 file changed, 16 insertions(+), 18 deletions(-)

diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index 66b733537c46..50f18985ed13 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c

@@ -209,28 +209,26 @@ static int iomap_read_inline_data(struct inode *inode, struct page *page,
                struct iomap *iomap)
 {
        size_t size = i_size_read(inode) - iomap->offset;
+       size_t poff = offset_in_page(iomap->offset);
        void *addr;

        if (PageUptodate(page))
-               return 0;
+               return PAGE_SIZE - poff;

-       /* inline data must start page aligned in the file */
-       if (WARN_ON_ONCE(offset_in_page(iomap->offset)))
-               return -EIO;

        memcpy(addr, iomap->inline_data, size);
-       memset(addr + size, 0, PAGE_SIZE - size);
+       memset(addr + size, 0, PAGE_SIZE - poff - size);
        kunmap_atomic(addr);
-       SetPageUptodate(page);
-       return 0;
+       iomap_set_range_uptodate(page, poff, PAGE_SIZE - poff);
+       return PAGE_SIZE - poff;
 }

 static inline bool iomap_block_needs_zeroing(struct inode *inode,

@@ -252,13 +250,8 @@ iomap_readpage_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
        unsigned poff, plen;
        sector_t sector;

-       if (iomap->type == IOMAP_INLINE) {
-               int ret = iomap_read_inline_data(inode, page, iomap);
-
-               if (ret)
-                       return ret;
-               return PAGE_SIZE;
-       }
+       if (iomap->type == IOMAP_INLINE)
+               return iomap_read_inline_data(inode, page, iomap);

        /* zero post-eof blocks as the page may be mapped */
        iop = iomap_page_create(inode, page);

@@ -593,10 +586,15 @@ __iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, int flags,
 static int iomap_write_begin_inline(struct inode *inode,
                struct page *page, struct iomap *srcmap)
 {
+       int ret;
+
        /* needs more work for the tailpacking case, disable for now */
        if (WARN_ON_ONCE(srcmap->offset != 0))
                return -EIO;
-       return iomap_read_inline_data(inode, page, srcmap);
+       ret = iomap_read_inline_data(inode, page, srcmap);
+       if (ret < 0)
+               return ret;
+       return 0;
 }

 static int
--

2.30.2