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Commit e56eb659 authored by Aneesh Kumar K.V's avatar Aneesh Kumar K.V Committed by Theodore Ts'o
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ext4: Don't claim block from group which has corrupt bitmap 



In ext4_mb_complex_scan_group, if the extent length of the newly
found extentet is greater than than the total free blocks counted
in group info, break without claiming the block.

Document different ext4_error usage, explaining the state with which we
continue if we mount with errors=continue

Signed-off-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: default avatarMingming Cao <cmm@us.ibm.com>
Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
parent 9df5643a

fs/ext4/mballoc.c

+15 −1
Original line number Diff line number Diff line
@@ -967,6 +967,10 @@ static void ext4_mb_generate_buddy(struct super_block *sb, 
		ext4_error(sb, __FUNCTION__,

			"EXT4-fs: group %lu: %u blocks in bitmap, %u in gd\n",

			group, free, grp->bb_free);

		/*

		 * If we intent to continue, we consider group descritor

		 * corrupt and update bb_free using bitmap value

		 */

		grp->bb_free = free;

	}
@@ -1822,7 +1826,7 @@ static void ext4_mb_complex_scan_group(struct ext4_allocation_context *ac, 
						EXT4_BLOCKS_PER_GROUP(sb), i);

		if (i >= EXT4_BLOCKS_PER_GROUP(sb)) {

			/*

			 * IF we corrupt the bitmap  we won't find any

			 * IF we have corrupt bitmap, we won't find any

			 * free blocks even though group info says we

			 * we have free blocks

			 */
@@ -1838,6 +1842,12 @@ static void ext4_mb_complex_scan_group(struct ext4_allocation_context *ac, 
			ext4_error(sb, __FUNCTION__, "%d free blocks as per "

					"group info. But got %d blocks\n",

					free, ex.fe_len);

			/*

			 * The number of free blocks differs. This mostly

			 * indicate that the bitmap is corrupt. So exit

			 * without claiming the space.

			 */

			break;

		}



		ext4_mb_measure_extent(ac, &ex, e4b);
@@ -3771,6 +3781,10 @@ static int ext4_mb_release_inode_pa(struct ext4_buddy *e4b, 
			(unsigned long) pa->pa_len);

		ext4_error(sb, __FUNCTION__, "free %u, pa_free %u\n",

						free, pa->pa_free);

		/*

		 * pa is already deleted so we use the value obtained

		 * from the bitmap and continue.

		 */

	}

	atomic_add(free, &sbi->s_mb_discarded);

	if (ac)