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Commit 345ee947 authored by Eric Whitney's avatar Eric Whitney Committed by Theodore Ts'o
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ext4: miscellaneous partial cluster cleanups 



Add some casts and rearrange a few statements for improved readability.
Some code can also be simplified and made more readable if we set
partial_cluster to 0 rather than to a negative value when we can tell
we've hit the left edge of the punched region.

Signed-off-by: default avatarEric Whitney <enwlinux@gmail.com>
Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
parent 5bf43760

fs/ext4/extents.c

+21 −18
Original line number Diff line number Diff line
@@ -2490,7 +2490,7 @@ static int ext4_remove_blocks(handle_t *handle, struct inode *inode, 
	 * at the beginning of the extent.  Instead, we make a note

	 * that we tried freeing the cluster, and check to see if we

	 * need to free it on a subsequent call to ext4_remove_blocks,

	 * or at the end of the ext4_truncate() operation.

	 * or at the end of ext4_ext_rm_leaf or ext4_ext_remove_space.

	 */

	flags |= EXT4_FREE_BLOCKS_NOFREE_FIRST_CLUSTER;
@@ -2501,8 +2501,8 @@ static int ext4_remove_blocks(handle_t *handle, struct inode *inode, 
	 * partial cluster here.

	 */

	pblk = ext4_ext_pblock(ex) + ee_len - 1;

	if ((*partial_cluster > 0) &&

	    (EXT4_B2C(sbi, pblk) != *partial_cluster)) {

	if (*partial_cluster > 0 &&

	    *partial_cluster != (long long) EXT4_B2C(sbi, pblk)) {

		ext4_free_blocks(handle, inode, NULL,

				 EXT4_C2B(sbi, *partial_cluster),

				 sbi->s_cluster_ratio, flags);
@@ -2528,7 +2528,7 @@ static int ext4_remove_blocks(handle_t *handle, struct inode *inode, 
	    && to == le32_to_cpu(ex->ee_block) + ee_len - 1) {

		/* tail removal */

		ext4_lblk_t num;

		unsigned int unaligned;

		long long first_cluster;



		num = le32_to_cpu(ex->ee_block) + ee_len - from;

		pblk = ext4_ext_pblock(ex) + ee_len - num;
@@ -2538,7 +2538,7 @@ static int ext4_remove_blocks(handle_t *handle, struct inode *inode, 
		 * used by any other extent (partial_cluster is negative).

		 */

		if (*partial_cluster < 0 &&

		    -(*partial_cluster) == EXT4_B2C(sbi, pblk + num - 1))

		    *partial_cluster == -(long long) EXT4_B2C(sbi, pblk+num-1))

			flags |= EXT4_FREE_BLOCKS_NOFREE_LAST_CLUSTER;



		ext_debug("free last %u blocks starting %llu partial %lld\n",
@@ -2549,21 +2549,24 @@ static int ext4_remove_blocks(handle_t *handle, struct inode *inode, 
		 * beginning of a cluster, and we removed the entire

		 * extent and the cluster is not used by any other extent,

		 * save the partial cluster here, since we might need to

		 * delete if we determine that the truncate operation has

		 * removed all of the blocks in the cluster.

		 * delete if we determine that the truncate or punch hole

		 * operation has removed all of the blocks in the cluster.

		 * If that cluster is used by another extent, preserve its

		 * negative value so it isn't freed later on.

		 *

		 * On the other hand, if we did not manage to free the whole

		 * extent, we have to mark the cluster as used (store negative

		 * cluster number in partial_cluster).

		 */

		unaligned = EXT4_PBLK_COFF(sbi, pblk);

		if (unaligned && (ee_len == num) &&

		    (*partial_cluster != -((long long)EXT4_B2C(sbi, pblk))))

			*partial_cluster = EXT4_B2C(sbi, pblk);

		else if (unaligned)

			*partial_cluster = -((long long)EXT4_B2C(sbi, pblk));

		else if (*partial_cluster > 0)

		 * If the whole extent wasn't freed, we've reached the

		 * start of the truncated/punched region and have finished

		 * removing blocks.  If there's a partial cluster here it's

		 * shared with the remainder of the extent and is no longer

		 * a candidate for removal.

		 */

		if (EXT4_PBLK_COFF(sbi, pblk) && ee_len == num) {

			first_cluster = (long long) EXT4_B2C(sbi, pblk);

			if (first_cluster != -*partial_cluster)

				*partial_cluster = first_cluster;

		} else {

			*partial_cluster = 0;

		}

	} else

		ext4_error(sbi->s_sb, "strange request: removal(2) "

			   "%u-%u from %u:%u\n",