e2fsck: fix sliding the directory block down on bigalloc

If we find a hole in a directory on a bigalloc filesystem, we need to
obey the cluster alignment rules when collapsing the gap to avoid
later complaints.

Specifically, the calculation of the new logical cluster number was
incorrect, and we need to ensure that the logical cluster alignment
respects the physical cluster alignment, since we've concluded that
the extent's logical block number is wrong.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

e2fsck/pass1.c

@@ -2568,9 +2568,9 @@ report_problem:
 			new_lblk = pb->last_block + 1;
 			if (EXT2FS_CLUSTER_RATIO(ctx->fs) > 1)
 				new_lblk = ((new_lblk +
-					     EXT2FS_CLUSTER_RATIO(ctx->fs)) &
-					    EXT2FS_CLUSTER_MASK(ctx->fs)) |
-					   (extent.e_lblk &
+					     EXT2FS_CLUSTER_RATIO(ctx->fs) - 1) &
+					    ~EXT2FS_CLUSTER_MASK(ctx->fs)) |
+					   (extent.e_pblk &
 					    EXT2FS_CLUSTER_MASK(ctx->fs));
 			pctx->blk = extent.e_lblk;
 			pctx->blk2 = new_lblk;

tests/f_holedir4/expect.1

@@ -0,0 +1,68 @@
+Pass 1: Checking inodes, blocks, and sizes
+Directory inode 12 block 211 should be at block 25.  Fix? yes
+
+Inode 12, i_size is 4096, should be 110592.  Fix? yes
+
+Inode 12, i_blocks is 128, should be 256.  Fix? yes
+
+Pass 2: Checking directory structure
+Directory inode 12 has an unallocated block #2.  Allocate? yes
+
+Directory inode 12 has an unallocated block #3.  Allocate? yes
+
+Directory inode 12 has an unallocated block #4.  Allocate? yes
+
+Directory inode 12 has an unallocated block #5.  Allocate? yes
+
+Directory inode 12 has an unallocated block #6.  Allocate? yes
+
+Directory inode 12 has an unallocated block #7.  Allocate? yes
+
+Directory inode 12 has an unallocated block #8.  Allocate? yes
+
+Directory inode 12 has an unallocated block #9.  Allocate? yes
+
+Directory inode 12 has an unallocated block #10.  Allocate? yes
+
+Directory inode 12 has an unallocated block #11.  Allocate? yes
+
+Directory inode 12 has an unallocated block #12.  Allocate? yes
+
+Directory inode 12 has an unallocated block #13.  Allocate? yes
+
+Directory inode 12 has an unallocated block #14.  Allocate? yes
+
+Directory inode 12 has an unallocated block #15.  Allocate? yes
+
+Directory inode 12 has an unallocated block #16.  Allocate? yes
+
+Directory inode 12 has an unallocated block #17.  Allocate? yes
+
+Directory inode 12 has an unallocated block #18.  Allocate? yes
+
+Directory inode 12 has an unallocated block #19.  Allocate? yes
+
+Directory inode 12 has an unallocated block #20.  Allocate? yes
+
+Directory inode 12 has an unallocated block #21.  Allocate? yes
+
+Directory inode 12 has an unallocated block #22.  Allocate? yes
+
+Directory inode 12 has an unallocated block #23.  Allocate? yes
+
+Directory inode 12 has an unallocated block #24.  Allocate? yes
+
+Pass 3: Checking directory connectivity
+Pass 3A: Optimizing directories
+Pass 4: Checking reference counts
+Pass 5: Checking group summary information
+Free blocks count wrong for group #0 (26, counted=25).
+Fix? yes
+
+Free blocks count wrong (416, counted=400).
+Fix? yes
+
+
+test_filesys: ***** FILE SYSTEM WAS MODIFIED *****
+test_filesys: 13/32 files (7.7% non-contiguous), 112/512 blocks
+Exit status is 1

tests/f_holedir4/expect.2

@@ -0,0 +1,11 @@
+Pass 1: Checking inodes, blocks, and sizes
+Inode 12, i_blocks is 3072, should be 128.  Fix? yes
+
+Pass 2: Checking directory structure
+Pass 3: Checking directory connectivity
+Pass 4: Checking reference counts
+Pass 5: Checking group summary information
+
+test_filesys: ***** FILE SYSTEM WAS MODIFIED *****
+test_filesys: 13/32 files (0.0% non-contiguous), 112/512 blocks
+Exit status is 1

tests/f_holedir4/name

@@ -0,0 +1 @@
+bigalloc directory with hole and misaligned extent after hole