xfs: fix regression in "cleanup xfs_dir2_block_getdents" (3d28e7e2) · Commits · 戴 / test

Commit ("xfs: cleanup xfs_dir2_block_getdents") introduced a getdents regression, when it converted the pointer arithmetics to offset calculations: offset is updated in the loop already for the next iteration, but the updated offset value is used incorrectly in two places, where we should have used the not-yet-updated value. This caused for example "git clean -ffdx" failures to cleanup certain directory structures when running in a container. Fix the regression by making sure we use proper offset in the loop body. Thanks to Christoph Hellwig for suggestion how to best fix the code. Cc: Christoph Hellwig <hch@lst.de> Fixes: ("xfs: cleanup xfs_dir2_block_getdents") Signed-off-by:

Tommi Rantala <tommi.t.rantala@nokia.com> Reviewed-by:

Christoph Hellwig <hch@lst.de> Reviewed-by:

Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by:

Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by:

Dave Chinner <dchinner@redhat.com>

fs/xfs/xfs_dir2_readdir.c

+7 −5

Original line number	Diff line number	Diff line
		@@ -147,7 +147,7 @@ xfs_dir2_block_getdents(
		xfs_off_t cook;
		struct xfs_da_geometry *geo = args->geo;
		int lock_mode;
		unsigned int offset;
		unsigned int offset, next_offset;
		unsigned int end;

		/*
		@@ -173,9 +173,10 @@ xfs_dir2_block_getdents(
		* Loop over the data portion of the block.
		* Each object is a real entry (dep) or an unused one (dup).
		*/
		offset = geo->data_entry_offset;
		end = xfs_dir3_data_end_offset(geo, bp->b_addr);
		while (offset < end) {
		for (offset = geo->data_entry_offset;
		offset < end;
		offset = next_offset) {
		struct xfs_dir2_data_unused *dup = bp->b_addr + offset;
		struct xfs_dir2_data_entry *dep = bp->b_addr + offset;
		uint8_t filetype;
		@@ -184,14 +185,15 @@ xfs_dir2_block_getdents(
		* Unused, skip it.
		*/
		if (be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG) {
		offset += be16_to_cpu(dup->length);
		next_offset = offset + be16_to_cpu(dup->length);
		continue;
		}

		/*
		* Bump pointer for the next iteration.
		*/
		offset += xfs_dir2_data_entsize(dp->i_mount, dep->namelen);
		next_offset = offset +
		xfs_dir2_data_entsize(dp->i_mount, dep->namelen);

		/*
		* The entry is before the desired starting point, skip it.

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