erofs-utils: lib: move block boundary check into __erofs_battach()

It should be guaranteed when buffers are attached, rather than
scattered everywhere.

Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20241219064331.2223001-2-hsiangkao@linux.alibaba.com

diff --git a/lib/cache.c b/lib/cache.c
index 66bbdca2f774307073bfc19665e2a670a3ba063d..1cc5007f81c7f7736fc2b1ef1790ae9d04e77020 100644 (file)
--- a/lib/cache.c
+++ b/lib/cache.c
@@ -69,7 +69,7 @@ static int __erofs_battach(struct erofs_buffer_block *bb,
                           struct erofs_buffer_head *bh,
                           erofs_off_t incr,
                           unsigned int alignsize,
-                          unsigned int extrasize,
+                          unsigned int inline_ext,
                           bool dryrun)
 {
        struct erofs_bufmgr *bmgr = bb->buffers.fsprivate;
@@ -78,11 +78,16 @@ static int __erofs_battach(struct erofs_buffer_block *bb,
        const unsigned int blkmask = blksiz - 1;
        erofs_off_t boff = bb->buffers.off;
        const erofs_off_t alignedoffset = roundup(boff, alignsize);
-       const int oob = cmpsgn(roundup(((boff - 1) & blkmask) + 1, alignsize) +
-                                       incr + extrasize, blksiz);
        bool tailupdate = false;
        erofs_blk_t blkaddr;
+       int oob;
 
+       /* inline data must never span block boundaries */
+       if (erofs_blkoff(sbi, alignedoffset + incr + blkmask)
+                       + inline_ext > blkmask)
+               return -ENOSPC;
+
+       oob = cmpsgn((alignedoffset & blkmask) + incr + inline_ext, blksiz);
        if (oob >= 0) {
                /* the next buffer block should be NULL_ADDR all the time */
                if (oob && list_next_entry(bb, list)->blkaddr != NULL_ADDR)
@@ -111,7 +116,7 @@ static int __erofs_battach(struct erofs_buffer_block *bb,
                                                BLK_ROUND_UP(sbi, boff);
                erofs_bupdate_mapped(bb);
        }
-       return ((alignedoffset + incr - 1) & blkmask) + 1;
+       return ((alignedoffset + incr + blkmask) & blkmask) + 1;
 }
 
 int erofs_bh_balloon(struct erofs_buffer_head *bh, erofs_off_t incr)
@@ -179,12 +184,10 @@ static int erofs_bfind_for_attach(struct erofs_bufmgr *bmgr,
                        continue;
                }
 
+               usedmax = ret + inline_ext;
                /* should contain all data in the current block */
-               used = ret + inline_ext;
-               DBG_BUGON(used > blksiz);
-
+               DBG_BUGON(usedmax > blksiz);
                bb = cur;
-               usedmax = used;
                break;
        }
 
@@ -209,11 +212,8 @@ skip_mapped:
                if (ret < 0)
                        continue;
 
-               used = (ret & (blksiz - 1)) + inline_ext;
-
-               /* should contain inline data in current block */
-               if (used > blksiz)
-                       continue;
+               used = ret + inline_ext;
+               DBG_BUGON(used > blksiz);
 
                /*
                 * remaining should be smaller than before or