ext4: optimize ext4_ext_precache for 0 depth (2f424a5a) · Commits · 戴 / test

This patch avoids the memory alloc & free path when depth is 0, since anyway there is no extra caching done in that case. So on checking depth 0, simply return early. Signed-off-by:

Ritesh Harjani <riteshh@linux.ibm.com> Reviewed-by:

Jan Kara <jack@suse.cz> Link: https://lore.kernel.org/r/93da0d0f073c73358e85bb9849d8a5378d1da539.1582880246.git.riteshh@linux.ibm.com Signed-off-by:

Theodore Ts'o <tytso@mit.edu>

fs/ext4/extents.c

+6 −3

Original line number	Diff line number	Diff line
		@@ -549,6 +549,12 @@ int ext4_ext_precache(struct inode *inode)
		down_read(&ei->i_data_sem);
		depth = ext_depth(inode);

		/* Don't cache anything if there are no external extent blocks */
		if (!depth) {
		up_read(&ei->i_data_sem);
		return ret;
		}

		path = kcalloc(depth + 1, sizeof(struct ext4_ext_path),
		GFP_NOFS);
		if (path == NULL) {
		@@ -556,9 +562,6 @@ int ext4_ext_precache(struct inode *inode)
		return -ENOMEM;
		}

		/* Don't cache anything if there are no external extent blocks */
		if (depth == 0)
		goto out;
		path[0].p_hdr = ext_inode_hdr(inode);
		ret = ext4_ext_check(inode, path[0].p_hdr, depth, 0);
		if (ret)

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