add REDIRECT

hc

2024-10-09 05e59e5fb0064c97a1c10921ecd549f2d4a58565

 kernel/fs/nilfs2/super.c
..
..
@@ -373,10 +373,31 @@
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 		goto out;
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 	}
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 	nsbp = (void *)nsbh->b_data + offset;
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-	memset(nsbp, 0, nilfs->ns_blocksize);
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+
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+	lock_buffer(nsbh);
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+	if (sb2i >= 0) {
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+		/*
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+		 * The position of the second superblock only changes by 4KiB,
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+		 * which is larger than the maximum superblock data size
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+		 * (= 1KiB), so there is no need to use memmove() to allow
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+		 * overlap between source and destination.
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+		 */
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+		memcpy(nsbp, nilfs->ns_sbp[sb2i], nilfs->ns_sbsize);
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+
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+		/*
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+		 * Zero fill after copy to avoid overwriting in case of move
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+		 * within the same block.
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+		 */
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+		memset(nsbh->b_data, 0, offset);
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+		memset((void *)nsbp + nilfs->ns_sbsize, 0,
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+		       nsbh->b_size - offset - nilfs->ns_sbsize);
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+	} else {
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+		memset(nsbh->b_data, 0, nsbh->b_size);
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+	}
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+	set_buffer_uptodate(nsbh);
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+	unlock_buffer(nsbh);
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 	if (sb2i >= 0) {
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-		memcpy(nsbp, nilfs->ns_sbp[sb2i], nilfs->ns_sbsize);
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 		brelse(nilfs->ns_sbh[sb2i]);
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 		nilfs->ns_sbh[sb2i] = nsbh;
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 		nilfs->ns_sbp[sb2i] = nsbp;
..
..
@@ -408,6 +429,15 @@
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 	devsize = i_size_read(sb->s_bdev->bd_inode);
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 	if (newsize > devsize)
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 		goto out;
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+
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+	/*
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+	 * Prevent underflow in second superblock position calculation.
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+	 * The exact minimum size check is done in nilfs_sufile_resize().
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+	 */
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+	if (newsize < 4096) {
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+		ret = -ENOSPC;
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+		goto out;
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+	}
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 	/*
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 	 * Write lock is required to protect some functions depending
..
..
@@ -474,6 +504,7 @@
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 		up_write(&nilfs->ns_sem);
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 	}
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+	nilfs_sysfs_delete_device_group(nilfs);
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 	iput(nilfs->ns_sufile);
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 	iput(nilfs->ns_cpfile);
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 	iput(nilfs->ns_dat);
..
..
@@ -1097,6 +1128,7 @@
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 	nilfs_put_root(fsroot);
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  failed_unload:
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+	nilfs_sysfs_delete_device_group(nilfs);
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 	iput(nilfs->ns_sufile);
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 	iput(nilfs->ns_cpfile);
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 	iput(nilfs->ns_dat);